Today's Message Index:
----------------------
1. 12:57 AM - Re: Oil Consumption (FLYaDIVE)
2. 05:24 AM - Re: Oil Consumption (flyv35b)
3. 05:32 AM - Re: Oil Consumption (flyv35b)
4. 06:49 AM - Re: Oil Consumption (flyv35b)
5. 06:51 AM - Re: Oil Consumption (923TE)
6. 07:22 AM - Re: Oil Consumption (flyv35b)
7. 07:42 AM - Re: Oil Consumption (923te)
8. 08:31 AM - Re: Oil Consumption (923te)
9. 08:46 AM - Re: Oil Consumption (flyv35b)
10. 09:53 AM - Re: Oil Consumption (Gary Vogt)
11. 09:59 AM - Re: Oil Consumption (FLYaDIVE)
12. 10:18 AM - Sodium filled valves (Gary Vogt)
13. 10:21 AM - Re: Oil Consumption (Gary Vogt)
14. 10:23 AM - Re: Oil Consumption (Gary Vogt)
15. 10:26 AM - Re: Oil Consumption (FLYaDIVE)
16. 08:00 PM - Re: Oil Consumption (Gary Vogt)
Message 1
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| Subject: | Re: Oil Consumption |
Gary:
I looked up Sam Heron and could not find anything. Can you post a link?
IF - IF - The cooling is kept to a minimum to allow heat transfer someone
has been feeding the industry a HUGE BLIVIT. It makes better sense to keep
the valve and guide clearance to a minimum to control valve and guide wear.
YOU DO NOT WANT THE VALVE SLOPPY AND FLOPPING AROUND. Think of SB-388!!!
AND if you want to take the path that the heat is mainly or REQUIRED to
be transferred through the Valve Head and Seat- That is true and all well
and good, BUT... What do you think would happen if the valve head LOOSES
contact surface because of SLOP between the valve guide and stem due to a
larger SLOPPY fit?
AND what about the change in material of the valve seat years ago to better
handle the heat?
AND there was a change in the valve guide material as well. Maybe not to
handle the heat transfer - But, to handle the ware. And where does ware
come from?
No, I would not change the tolerance between valve stem and guide. I would
just REMOVE as much heat as possible while allowing two actions to take
place:
1 - The material coefficient to keep the valve and guide tolerances.
2 - The oil to remain in its optimum range.
Remember COKING is the burning of oil. Keep the oil from burning and there
is no coking.
No coking equals no valve failure - At least not from coking.
Barry
============================
On Wed, Feb 22, 2012 at 10:38 PM, Gary Vogt <teamgrumman@yahoo.com> wrote:
> Look up the original work by Sam Heron. The oil does not do the cooling.
> At all. You only want a minimum of oil on the valve stems for
> lubrication. If you're flooding the stem with oil, some will get into the
> guide and the heat will cook it. In sodium filled valves, the cooling is
> done through the valve seat and valve guide.
>
> Sodium filled valves are used in a lot of top fuel dragsters. For a
> reason.
>
> ------------------------------
> *From:* FLYaDIVE <flyadive@gmail.com>
> *To:* teamgrumman-list@matronics.com
> *Sent:* Wednesday, February 22, 2012 6:59 PM
>
> *Subject:* Re: TeamGrumman-List: Oil Consumption
>
> Gary said:
> They are wrong. Spraying extra oil on the valve stem causes coking on the
> valves. Oil flow to the rocker boxes on an engine with sodium valves is
> intentionally limited.
>
> The reality is, sodium filled valves do their work by direct metal to
> metal contact. Or as close to that as possible.
>
>
> Gary:
>
> Now that does not make sense. I don't think anyone is around that was
> involved in the original design of the Lycoming engine. The idea of a
> sodium filled valve and the extra transfer of heat because of the sodium is
> feasible but has proven short of goal. Our problem has always been over
> heating of the exhaust valve and coking on the stem of that valve.
> Continental uses solid stem valves and their failure mode is the same as
> Lycoming. There is no way of collecting data as to how many Lycoming and
> Continental valve failures there are.
> BUT! Isn't it COKING on the valve that causes the problem? AND... What
> is COKING? Coking is the BURNING of OIL with the subsequent build up
> that causes the valve to stick. When they stick in the DOWN position the
> piston comes up to smash the valve head and bend the valve shank.
> SO! HOW WOULD ONE PREVENT THE COKING?
> BY LOWERING THE TEMPERATURE THAT CAUSES THE COKING.
> AND HOW WOULD ONE DO THAT?
> BY INCREASING THE COOLING BY INCREASING THE OIL FLOW OVER THE VALVE STEM.
> No, I'm not yelling, just emphasing the point.
>
> Now, if this does not make sense, please explain why. I cannot accept the
> idea that minimal oil for heat transfer is the way to go or the intent.
>
> Barry
>
> Here are my thoughts:
> No mater how good or bad the heat transfer is between metal to meatal
> (something OIL is the medium that carries the heat away.
>
>
> *http://www.matronics.com/Navigator?TeamGrumma====================
> *
>
>
> *
>
> *
>
>
Message 2
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| Subject: | Re: Oil Consumption |
On 2/22/2012 6:32 PM, Gary Vogt wrote:
>> 30 years ago I called Lycoming and asked to talk to one of the
>> engineers. I wanted to know which rocker went on which valve. You see,
>> my <700 hr Cheetah had them one way on one side and the other way on
>> the other side. Both local AP/IAs didn't know. I eventually talked to
>> 6 engineers. The last one gave me a phone number for a guy who worked
>> for Lycoming 'in the old days.' His name was Wayne. Nice guy. He told
>> me about the work done on the engines 'in the old days' and told me
>> the correct order for the rockers. My engine had been assembled wrong
>> at the factory.
Bill Marvel had a new engine give to him from Lycoming free of charge
because all the intake and exhaust rocker arms were swaped. They since
have gone to only one part (the previous exhaust rocker with the
"squirt" hole) so that they can't be mixed up. There is so little oil
up there I'm not sure it makes any difference one way or the other.
Cliff
Message 3
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| Subject: | Re: Oil Consumption |
On 2/22/2012 7:39 PM, Gary Vogt wrote:
> Not likely. However, it wasn't long after talking to Lycoming that they
> came out with a common rocker for both intake and exhaust.
I suspect it was more likely due to Bill Marvel's dialog with Lycoming
that resulted in this.
Cliff
Message 4
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| Subject: | Re: Oil Consumption |
On 2/22/2012 6:59 PM, FLYaDIVE wrote:
>> Gary said:
>> They are wrong. Spraying extra oil on the valve stem causes coking on
>> the valves. Oil flow to the rocker boxes on an engine with sodium
>> valves is intentionally limited.
>>
>> The reality is, sodium filled valves do their work by direct metal to
>> metal contact. Or as close to that as possible.
>
> Gary:
>
> Now that does not make sense. I don't think anyone is around that was
> involved in the original design of the Lycoming engine. The idea of a
> sodium filled valve and the extra transfer of heat because of the sodium
> is feasible but has proven short of goal. Our problem has always been
> over heating of the exhaust valve and coking on the stem of that valve.
> Continental uses solid stem valves and their failure mode is the same as
> Lycoming. There is no way of collecting data as to how many Lycoming
> and Continental valve failures there are.
> BUT! Isn't it COKING on the valve that causes the problem? AND... What
> is COKING? Coking is the BURNING of OIL with the subsequent build up
> that causes the valve to stick. When they stick in the DOWN position
> the piston comes up to smash the valve head and bend the valve shank.
> SO! HOW WOULD ONE PREVENT THE COKING?
> BY LOWERING THE TEMPERATURE THAT CAUSES THE COKING.
> AND HOW WOULD ONE DO THAT?
> BY INCREASING THE COOLING BY INCREASING THE OIL FLOW OVER THE VALVE
> STEM. No, I'm not yelling, just emphasing the point.
> Now, if this does not make sense, please explain why. I cannot accept
> the idea that minimal oil for heat transfer is the way to go or the intent.
>
> Barry
>
> Here are my thoughts:
> No mater how good or bad the heat transfer is between metal to meatal
> (something OIL is the medium that carries the heat away.
>
"I looked up Sam Heron and could not find anything. Can you post a link?
IF - IF - The cooling is kept to a minimum to allow heat transfer
someone has been feeding the industry a HUGE BLIVIT. It makes better
sense to keep the valve and guide clearance to a minimum to control
valve and guide wear. YOU DO NOT WANT THE VALVE SLOPPY AND FLOPPING
AROUND. Think of SB-388!!! AND if you want to take the path that the
heat is mainly or REQUIRED to be transferred through the Valve Head and
Seat- That is true and all well and good, BUT... What do you think would
happen if the valve head LOOSES contact surface because of SLOP between
the valve guide and stem due to a larger SLOPPY fit?
AND what about the change in material of the valve seat years ago to
better handle the heat?
AND there was a change in the valve guide material as well. Maybe not
to handle the heat transfer - But, to handle the ware. And where does
ware come from?
No, I would not change the tolerance between valve stem and guide. I
would just REMOVE as much heat as possible while allowing two actions to
take place:
1 - The material coefficient to keep the valve and guide tolerances.
2 - The oil to remain in its optimum range.
Remember COKING is the burning of oil. Keep the oil from burning and
there is no coking.
No coking equals no valve failure - At least not from coking."
Barry
Gary is referring to an old SAE paper on sodium exhaust valve stems,
which may have had an influence on Lycoming changing to their half inch
sodium cooled exhaust valves. I don't know that they intentionally
limited the oil to the exhaust guide as that may have been dictated by
the old automotive lifter design they chose to use years before.
At any rate there is precious little oil flow to the exhaust rocker
area, especially on the RH side of the engine. Certainly not enough to
carry away any significant amount of heat, but just engouh to coke up
the valve stem/guide under the right operating conditions.
In all the Tiger engines I have worked on and disassembled the valves
from I don't ever recall seeing a stuck exhaust valve due to coking. I
think this happens much more often on the 150 hp engines and planes that
are operated at low throttle settings for considerable time and at full
rich mixture settings. I think this is a faily uncommon failure more
for a Tiger that is operated at high power and high rpm on x-country
flights. These engines tend to wear out the guides and looses up the
clearance before they can coke up.
Since the sodium valves rely on transferring a good deal (maybe a
majority) of the heat up the stem and through the guide to the head for
cooling, then this interface is pretty important. Continental engines
transfer heat to the valve seat as the primary heat path. Take a look
at SKy Ranch Engineering Manual by John Schwaner for a detailed
discussion of this.
The problem seems to be that guide wear is rapid under these conditions
of high heat and material compatibility (hence the HC content guide
change) and as the clearance increases the ability to transfer heat to
the guide decreases, causing the valve to run hotter and wear the guide
even quicker and fatigue the valve. Eventually the valve head will
break off as the valve is weakened and hits the seat cockeyed. Happens
all the time if you ignor the wear and let it go long enough. Lycoming
knows this, hence SB388C. They have done little to really solve the
problem.
I suspect that they may be some point where enough oil could be
introduced and continuously flowed around the guide area to extract a
significant amount of heat and lower the temperature to the point it
could not coke up. How much that would take, who knows. I thought that
was what Lycoming and Mooney were attempting to do on the parallel valve
IO-540 engines in the Mooneys which were having serious valve problems
on planes that only had 250 hours on them. Owners were not happy. Gary
says that didn't work. I don't know if that is so or not. It would be
nice to see the service reports and results after the change but that
info probably is not available.
One thing is interesting is that Bill Marvel has loss of compression,
exhaust valve leakage and wear problems with his old Tiger in time
intervals as low as 250 hrs to 400 hrs on a routine basis. He flew the
plane entirely on x-country trips at altitude at 2700 rpm. Since
building his RV-8A with the same engine but with a CS prop operating at
2300 rpm and full throttle he has had no valve problems in over 1200 hrs
(or maybe more).
Personally, I'm not so sure that the sodium cooled exhaust valves have
not aggravated the guide wear problem. With the HC guides and SB388C
the liability risk of an exhaust valve failure is reduced and the owner
is just left with a low grain headache rather than a migraine one!
I disassembled a IO-520 Continental engine with 1700 hrs on it (TBO) and
found the worst exhaust valve guide had only about .008" wear. Cylinder
bore wear was barely .003" at the top in the choke area. The choke was
gone and the cylinder was now straight, which according to Chuck Ney is
better. No cylinder work or any other work besides spark plugs and
magneto inspection was ever done on this engine. The engine in my
Bonanza that was replaced by this one after overhaul went 700 hrs beyond
TBO with very few cylinder problems.
Cliff
Message 5
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| Subject: | Re: Oil Consumption |
Bill Scott says he swaps parts in the hydraulic lifters to get the greatest clearances
allowed by the Lycoming specifications. His research shows this parts
swapping gets more oil on the valve stem. I had him do this on 2 of my engines
after reading all their articles and having my Dad read the articles. Dad thought
it was a good idea. He worked with sodium filled valves on B-29's and back
in the day gained a lot of field knowledge on how to keep them running over
the Pacific. I have often been bothered by the contradictory information. It makes
sense that putting any oil on the valve stem would lead to coking if the
stem is going to run hot enough to cook the oil. The valve guide material is self
lubricating and theoretically doesn't need additional oil to work properly.
The answer Lycoming gives us is to measure "slop" and replace guides.
It would be great if Lycoming was owned by a huge company that had the incentive
to develop a better solution. Like these guys
http://www.komatsu.com/CompanyInfo/profile/report/pdf/152-04_E.pdf
Ned
On Feb 23, 2012, at 7:24 AM, flyv35b <flyv35b@minetfiber.com> wrote:
>
> On 2/22/2012 6:32 PM, Gary Vogt wrote:
>
>>> 30 years ago I called Lycoming and asked to talk to one of the
>>> engineers. I wanted to know which rocker went on which valve. You see,
>>> my <700 hr Cheetah had them one way on one side and the other way on
>>> the other side. Both local AP/IAs didn't know. I eventually talked to
>>> 6 engineers. The last one gave me a phone number for a guy who worked
>>> for Lycoming 'in the old days.' His name was Wayne. Nice guy. He told
>>> me about the work done on the engines 'in the old days' and told me
>>> the correct order for the rockers. My engine had been assembled wrong
>>> at the factory.
>
> Bill Marvel had a new engine give to him from Lycoming free of charge because
all the intake and exhaust rocker arms were swaped. They since have gone to
only one part (the previous exhaust rocker with the "squirt" hole) so that they
can't be mixed up. There is so little oil up there I'm not sure it makes any
difference one way or the other.
>
> Cliff
>
>
>
>
Message 6
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| Subject: | Re: Oil Consumption |
On 2/23/2012 6:51 AM, 923TE wrote:
> --> TeamGrumman-List message posted by: 923TE<923te@att.net>
>
> Bill Scott says he swaps parts in the hydraulic lifters to get the greatest clearances
allowed by the Lycoming specifications. His research shows this parts
swapping gets more oil on the valve stem. I had him do this on 2 of my engines
after reading all their articles and having my Dad read the articles. Dad thought
it was a good idea. He worked with sodium filled valves on B-29's and back
in the day gained a lot of field knowledge on how to keep them running over
the Pacific. I have often been bothered by the contradictory information. It
makes sense that putting any oil on the valve stem would lead to coking if the
stem is going to run hot enough to cook the oil. The valve guide material is
self lubricating and theoretically doesn't need additional oil to work properly.
>
> The answer Lycoming gives us is to measure "slop" and replace guides.
>
> It would be great if Lycoming was owned by a huge company that had the incentive
to develop a better solution. Like these guys
>
> http://www.komatsu.com/CompanyInfo/profile/report/pdf/152-04_E.pdf
>
> Ned
>
> On Feb 23, 2012, at 7:24 AM, flyv35b<flyv35b@minetfiber.com> wrote:
>
>> --> TeamGrumman-List message posted by: flyv35b<flyv35b@minetfiber.com>
>>
>> On 2/22/2012 6:32 PM, Gary Vogt wrote:
>>
>>>> 30 years ago I called Lycoming and asked to talk to one of the
>>>> engineers. I wanted to know which rocker went on which valve. You see,
>>>> my<700 hr Cheetah had them one way on one side and the other way on
>>>> the other side. Both local AP/IAs didn't know. I eventually talked to
>>>> 6 engineers. The last one gave me a phone number for a guy who worked
>>>> for Lycoming 'in the old days.' His name was Wayne. Nice guy. He told
>>>> me about the work done on the engines 'in the old days' and told me
>>>> the correct order for the rockers. My engine had been assembled wrong
>>>> at the factory.
>>
>> Bill Marvel had a new engine give to him from Lycoming free of charge because
all the intake and exhaust rocker arms were swaped. They since have gone to
only one part (the previous exhaust rocker with the "squirt" hole) so that they
can't be mixed up. There is so little oil up there I'm not sure it makes any
difference one way or the other.
>>
>> Cliff
>>
What Bill is doing is testing the bleed down rate of the hydraulic unit
and pickiing the ones with the highest bleed down rate for use on the
exhaust valves. That way they pump or bleed slightly more oil up the
pushrod and to the rocker arm. But it is still precious little.
BTW, Lycoming is owned by a large company called Textron. They've got
the money but no incentive and no competition for their medium power 4
cylinder engines. Heck, why change when you can sell more parts? And
the FAA makes it costly and difficult for anyone else to get in the
game. ECI has done a pretty good job but the cost is about the same.
Cliff
Message 7
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| Subject: | Re: Oil Consumption |
So all the old farts are dead and now it's our generation that's the old far
ts and were supposed to be the experts on 1940's technology?
Hmmm
Well I'm no expert but I'm thinking that maybe we should go back to what the
really old farts were doing when they converted the engine for aircraft and
just use push rods and rockers with holes in them on the intake and NOT the
exhaust since the really old farts originally made it to conduct a dribble o
f oil ONLY ON THE INTAKE VALVE STEM
Is that how you built your current engine Gary?
On Feb 22, 2012, at 12:35 PM, Gary Vogt <teamgrumman@yahoo.com> wrote:
> I could give you all of the references to how to treat sodium filled valve
s, but then I'd have to go against everything Bill and Bill say.
>
> They are wrong. Spraying extra oil on the valve stem causes coking on the
valves. Oil flow to the rocker boxes on an engine with sodium valves is in
tentionally limited.
>
> The reality is, sodium filled valves do their work by direct metal to meta
l contact. Or as close to that as possible.
>
> The intakes could have seals. The intake (originally) used a dribble meth
od to keep oil flow to a minimum. With very little oil on the stem, very lit
tle was sucked in.
>
> The exhaust doesn't need them because the pressure pushes exhaust gases up
the stem. What little oil is squirted by the rocker is just enough to keep
the stem lubricated.
>
> Lycoming had a knee jerk reaction to the valves in a Mooney. It doesn't h
elp. Their research consisted of a corporate meeting. Had that corporate d
ecision not been a waste of manpower, time, and money, all new engines would
have the retro fit.
>
> 30 years ago I called Lycoming and asked to talk to one of the engineers.
I wanted to know which rocker went on which valve. You see, my <700 hr Che
etah had them one way on one side and the other way on the other side. Both
local AP/IAs didn't know. I eventually talked to 6 engineers. The last on
e gave me a phone number for a guy who worked for Lycoming 'in the old days.
' His name was Wayne. Nice guy. He told me about the work done on the eng
ines 'in the old days' and told me the correct order for the rockers. My en
gine had been assembled wrong at the factory.
>
> From: 923te <923te@att.net>
> To: teamgrumman-list@matronics.com
> Sent: Wednesday, February 22, 2012 9:24 AM
> Subject: Re: TeamGrumman-List: Oil Consumption
>
> Bill Marvel and Bill Scott make for some very interesting reading and have
a very strong argument in the following articles:
> http://egaa.home.mindspring.com/valves.html
>
> Especially this article:
> http://egaa.home.mindspring.com/engine2.htm
> about the Lycoming TIO-540-AF1A Oil Cooled Exhaust Valve Guide Kit
>
> Their arguments seem to be verified by what Lycoming did to cool the exhau
st valves with more oil flow onto the stems.
>
> I agree that the valve stem seals certainly go counter to trying to cool t
hem.
> I guess it just depends on what you are trying to do. It's a catch 22 isn'
t it?
>
> Sure would be great to see some R&D by Lycolming on these issues.
> ----- Original Message -----
> From: Gary Vogt
> To: teamgrumman-list@matronics.com
> Sent: Tuesday, February 21, 2012 12:37 PM
> Subject: Re: TeamGrumman-List: Oil Consumption
>
> Kinda makes that whole 'squirting oil at the valve stem' seem silly now. N
ot enough exposed to do any extra cooling.
>
> From: 923TE <923te@att.net>
> To: "teamgrumman-list@matronics.com" <teamgrumman-list@matronics.com>
> Sent: Tuesday, February 21, 2012 8:16 AM
> Subject: Re: TeamGrumman-List: Oil Consumption
>
> Yes I would be most interested in sealing the intake valves but the certif
ied Continentals seal both and the RV guys that are into this have sealed bo
th. I hear that Lycon even machines the guide to fit a seal on it.
>
> Apparently with Gapless rings, you suck a lot more oil so they started usi
ng the seals
> Check it out here:
>
> http://www.vansairforce.com/community/showthread.php?t=69483&highlight=
Gapless+rings+seals&page=2
>
> http://www.vansairforce.com/community/showthread.php?t=56297&highlight=
Gapless+rings+seals
>
> See the red seal?
>
>
>
>
>
>
> Ned
>
> <><
>
> On Feb 21, 2012, at 7:36 AM, flyv35b <flyv35b@minetfiber.com> wrote:
>
> >
> > On 2/20/2012 6:47 PM, Gary Vogt wrote:
> >> Seals won't work on sodium filled valves. These guides are designed to
> >> be run with a minimum clearance.
> >
> > Of course. I think he meant the intake valves, where they would work.
> >
> >
> >
> >
>
> <pre><b><font size=3D2 color="#000000" face=3D"courier 3D=3D=3D=
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>
> </b></font></pre>
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Message 8
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| Subject: | Re: Oil Consumption |
BTW, Lycoming is owned by a large company called Textron. They've got
the money but no incentive and no competition for their medium power 4
cylinder engines. Heck, why change when you can sell more parts? And
the FAA makes it costly and difficult for anyone else to get in the
game. ECI has done a pretty good job but the cost is about the same.
Cliff
I agree except that Textron is less than 1/4 the size of Komatsu.
If Komatsu owned Textron then maybe....
Message 9
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| Subject: | Re: Oil Consumption |
On 2/23/2012 8:34 AM, 923te wrote:
> BTW, Lycoming is owned by a large company called Textron. They've got
> the money but no incentive and no competition for their medium power 4
> cylinder engines. Heck, why change when you can sell more parts? And
> the FAA makes it costly and difficult for anyone else to get in the
> game. ECI has done a pretty good job but the cost is about the same.
>
> Cliff
>
> I agree except that Textron is less than 1/4 the size of Komatsu.
> If Komatsu owned Textron then maybe....
>
> *
I doubt it. I think it is more related to desire and competition that
forces you to make a better product and/or lower the cost.
Message 10
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| Subject: | Re: Oil Consumption |
The guides on sodium filled valves are supposed to be tight. -Not sloppy.
=0A=0AMaterial change (guide) was to reduce wear and keep the clearance tig
ht.=0AMaterial change (valve) was for wear. -Lead is a lubricant. -Take
out the lead, you need a better valve.=0A=0AI can't believe you can't find
a reference to Sam Heron.=0A=0Ahere is one reference. -I'm not going to
do your homework.=0Ahttp://www.agelessengines.com/j5.htm=0A=0A=0A=0A=0A____
____________________________=0A From: FLYaDIVE <flyadive@gmail.com>=0ATo: t
eamgrumman-list@matronics.com =0ASent: Thursday, February 23, 2012 12:56 AM
=0ASubject: Re: TeamGrumman-List: Oil Consumption=0A =0A=0AGary:=0A=0AI loo
ked up Sam Heron and could not find anything. -Can you post a link?=0A=0A
IF - IF - The cooling is kept to a-minimum-to allow heat transfer someo
ne has been feeding the industry a HUGE BLIVIT. -It makes better sense to
keep the valve and guide clearance to a minimum to control valve and guide
wear. -YOU DO NOT WANT THE VALVE SLOPPY AND FLOPPING AROUND. -Think of
SB-388!!! -AND if you want to take the path that the heat is mainly or R
EQUIRED to be-transferred-through the Valve Head and Seat- That is true
and all well and good, BUT... What do you think would happen if the valve
head LOOSES contact surface because of SLOP between the valve guide and ste
m due to a larger SLOPPY fit? -=0AAND what about the change in material o
f the valve seat years ago to better handle the heat?=0AAND there was a cha
nge in the valve guide material as well. -Maybe not to handle the heat tr
ansfer - But, to handle the ware. And where does ware come from? -=0ANo,
I would not change the tolerance between valve stem and guide. -I would j
ust REMOVE as much heat as-possible while allowing two actions to take pl
ace:=0A1 - The material-coefficient-to keep the valve and guide toleran
ces.=0A2 - The oil to remain in its-optimum-range.=0ARemember COKING is
the burning of oil. -Keep the oil from burning and there is no coking.
=0ANo coking equals no valve failure - At least not from coking.=0A=0ABarry
=0A========================
======0A=0A=0A=0A=0A=0AOn Wed, Feb 22, 2012 at 10:38 PM, Gary Vog
t <teamgrumman@yahoo.com> wrote:=0A=0ALook up the original work by Sam Hero
n. -The oil does not do the cooling. -At all. -You only want a minimu
m of oil on the valve stems for lubrication. -If you're flooding the stem
with oil, some will get into the guide and the heat will cook it. -In so
dium filled valves, the cooling is done through the valve seat and valve gu
ide.=0A>=0A>=0A>Sodium filled valves are used in a lot of top fuel dragster
s. -For a reason.=0A>=0A>=0A>=0A>________________________________=0A> Fro
m: FLYaDIVE <flyadive@gmail.com>=0A>To: teamgrumman-list@matronics.com =0A>
Sent: Wednesday, February 22, 2012 6:59 PM=0A>=0A>Subject: Re: TeamGrumman-
List: Oil Consumption=0A> =0A>=0A>Gary said:=0A>>They are wrong. -Sprayin
g extra oil on the valve stem causes coking on the valves. -Oil flow to t
he rocker boxes on an engine with sodium valves is intentionally limited.
=0A>>=0A>>=0A>>The reality is, sodium filled valves do their work by direct
metal to metal contact. -Or as close to that as possible.-=0A>=0A>=0A>
Gary:=0A>=0A>=0A>Now that does not make sense. -I don't think anyone is a
round that was involved in the-original-design of the Lycoming engine.
-The idea of a sodium filled valve and the extra transfer of heat because
of the sodium is-feasible-but has proven short of goal. -Our problem
has always been over heating of the exhaust valve and coking on the stem o
f that valve. -Continental-uses solid stem valves and their failure mod
e is the same as Lycoming. - There is no way of collecting data as to how
many Lycoming and Continental valve failures there are.=0A>BUT! -Isn't i
t COKING on the valve that causes the problem? -AND... What is COKING?
-Coking is the BURNING of OIL with the-subsequent build up that causes
the valve to stick. -When they stick in the DOWN position the piston come
s up to smash the valve head and bend the valve shank.=0A>SO! -HOW WOULD
ONE PREVENT THE COKING? -=0A>BY LOWERING THE TEMPERATURE THAT CAUSES THE
COKING.=0A>AND HOW WOULD ONE DO THAT?=0A>BY INCREASING THE COOLING BY INCRE
ASING THE OIL FLOW OVER THE VALVE STEM. -No, I'm not yelling, just-emph
asing-the point.=0A>-=0A>Now, if this does not make sense, please expla
in why. -I cannot accept the idea that-minimal-oil for heat transfer
is the way to go or the intent.=0A>=0A>=0A>Barry=0A>=0A>=0A>Here are my tho
ughts:=0A>No mater how good or bad the heat transfer is between metal to me
atal (something OIL is the medium that carries the heat away.=0A>=0A>=0A>
=0A>=0A>http://www.matronics.com/Navigator?TeamGrumma=======
============== =0A>=0A>=0A>st" target="_blank
">http://www.matronics.com/Navigator?TeamGrumman-List=0Atp://forums.matroni
===========
Message 11
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| Subject: | Re: Oil Consumption |
Hi Cliff:
I believe it DOES make a difference.
Years back when I first purchased my plane I lost a cylinder. Upon pulling
the cylinder and doing an inspection I found that the Exhaust and Intake
Rockers were swapped. The Intake Rocker for those that do not know has the
oil squirt hole facing AWAY from the valve [they face the valve on the
Exhaust]. This may not matter on the INTAKE Valve but - - - Inspection
showed High Heat on the Rocker Arm and on the Rocker Shaft ONLY in the area
of the Intake Rocker- - WHERE it was incorrectly installed on the Exhaust
Valve..
Is this 100% proof... Maybe not! BUT, it was the ONLY Rocker that was mixed
up.
When I had the engine MAJORED, I requested that ALL the rockers be EXHAUST
ROCKERS. And there is a SB by Lycoming allowing it. I did the research
and had to inform the engine shop of this SB.
Barry
On Thu, Feb 23, 2012 at 8:24 AM, flyv35b <flyv35b@minetfiber.com> wrote:
>
> On 2/22/2012 6:32 PM, Gary Vogt wrote:
>
> 30 years ago I called Lycoming and asked to talk to one of the
>>> engineers. I wanted to know which rocker went on which valve. You see,
>>> my <700 hr Cheetah had them one way on one side and the other way on
>>> the other side. Both local AP/IAs didn't know. I eventually talked to
>>> 6 engineers. The last one gave me a phone number for a guy who worked
>>> for Lycoming 'in the old days.' His name was Wayne. Nice guy. He told
>>> me about the work done on the engines 'in the old days' and told me
>>> the correct order for the rockers. My engine had been assembled wrong
>>> at the factory.
>>>
>>
> Bill Marvel had a new engine give to him from Lycoming free of charge
> because all the intake and exhaust rocker arms were swaped. They since
> have gone to only one part (the previous exhaust rocker with the "squirt"
> hole) so that they can't be mixed up. There is so little oil up there I'm
> not sure it makes any difference one way or the other.
>
> Cliff
>
>
Message 12
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| Subject: | Sodium filled valves |
"I disassembled a IO-520 Continental engine with 1700 hrs on it (TBO) and f
ound the worst exhaust valve guide had only about .008" wear.- Cylinder b
ore wear was barely .003" at the top in the choke area.- The choke was go
ne and the cylinder was now straight, which according to Chuck Ney is bette
r.- No cylinder work or any other work besides spark plugs and magneto in
spection was ever done on this engine.- The engine in my Bonanza that was
replaced by this one after overhaul went 700 hrs beyond TBO with very few
cylinder problems."=0A=0ACliff, I have a customer with an engine coming up
on 1900 hours. -It's never been apart. -It's already schedule for a LyC
on overhaul next year. - Should be interesting.=0A=0AWhen I bought my Tig
er, it had 1100 hours on it. -I wanted new cylinders and was going to hav
e Lycon overhaul the 1100 hr cylinders. -The guides were fine. -The exh
aust ports were full of cracks. -There was so much varnish on the inside
of the engine from short flights and sitting long periods that I could scra
pe it out with my finger nails. -Think 1956 Ford 312 that has never had t
he oil changed. -It was awful.-=0A=0AI removed the sump and used a bras
s wire brush to scrape all the crap out. -I then flushed 5 gallons of sol
vent under high pressure through all the galleys. -3 years later the oil
pick up finger screen still had crud in it. -Runs clean now. -But, wow,
not a good way to treat an engine.=0A=0ASodium filled valves have a long h
istory. -Solid stem valves even loner. -Either method is suitable when
setup correctly. -Either method is terrible if not setup correctly. -I
like the sodium filled valves. -They transfer more heat away from the val
ve head than does the solid valve. -Sodium filled valves are lighter and
less light to cause valve float (not really a problem in our engine when op
erated less than 3400 rpm). -Some production Chevy engines use sodium fil
led valves.=0A=0A________________________________=0A From: flyv35b <flyv35b
@minetfiber.com>=0ATo: teamgrumman-list@matronics.com =0ASent: Thursday, Fe
bruary 23, 2012 6:48 AM=0ASubject: Re: TeamGrumman-List: Oil Consumption=0A
>=0A=0AOn 2/22/2012 6:59 PM, FLYaDIVE wrote:=0A>> Gary said:=0A>> They are
wrong.- Spraying extra oil on the valve stem causes coking on=0A>> the va
lves.- Oil flow to the rocker boxes on an engine with sodium=0A>> valves
is intentionally limited.=0A>> =0A>> The reality is, sodium filled valves d
o their work by direct metal to=0A>> metal contact.- Or as close to that
as possible.=0A> =0A> Gary:=0A> =0A> Now that does not make sense.- I don
't think anyone is around that was=0A> involved in the original design of t
he Lycoming engine. The idea of a=0A> sodium filled valve and the extra tra
nsfer of heat because of the sodium=0A> is feasible but has proven short of
goal.- Our problem has always been=0A> over heating of the exhaust valve
and coking on the stem of that valve.=0A> Continental uses solid stem valv
es and their failure mode is the same as=0A> Lycoming.- There is no way
of collecting data as to how many Lycoming=0A> and Continental valve failur
es there are.=0A> BUT!- Isn't it COKING on the valve that causes the prob
lem?- AND... What=0A> is COKING?- Coking is the BURNING of OIL with the
subsequent build up=0A> that causes the valve to stick.- When they stick
in the DOWN position=0A> the piston comes up to smash the valve head and b
end the valve shank.=0A> SO!- HOW WOULD ONE PREVENT THE COKING?=0A> BY LO
WERING THE TEMPERATURE THAT CAUSES THE COKING.=0A> AND HOW WOULD ONE DO THA
T?=0A> BY INCREASING THE COOLING BY INCREASING THE OIL FLOW OVER THE VALVE
=0A> STEM.- No, I'm not yelling, just emphasing the point.=0A> Now, if th
is does not make sense, please explain why.- I cannot accept=0A> the idea
that minimal oil for heat transfer is the way to go or the intent.=0A> =0A
> Barry=0A> =0A> Here are my thoughts:=0A> No mater how good or bad the hea
t transfer is between metal to meatal=0A> (something OIL is the medium that
carries the heat away.=0A> =0A"I looked up Sam Heron and could not find an
ything.- Can you post a link?=0A=0AIF - IF - The cooling is kept to a min
imum to allow heat transfer someone has been feeding the industry a HUGE BL
IVIT.- It makes better sense to keep the valve and guide clearance to a m
inimum to control valve and guide wear.- YOU DO NOT WANT THE VALVE SLOPPY
AND FLOPPING AROUND.- Think of SB-388!!!- AND if you want to take the
path that the heat is mainly or REQUIRED to be transferred through the Valv
e Head and Seat- That is true and all well and good, BUT... What do you thi
nk would happen if the valve head LOOSES contact surface because of SLOP be
tween the valve guide and stem due to a larger SLOPPY fit?=0AAND what about
the change in material of the valve seat years ago to better handle the he
at?=0AAND there was a change in the valve guide material as well.- Maybe
not to handle the heat transfer - But, to handle the ware. And where does w
are come from?=0ANo, I would not change the tolerance between valve stem an
d guide.- I would just REMOVE as much heat as possible while allowing two
actions to take place:=0A1 - The material coefficient to keep the valve an
d guide tolerances.=0A2 - The oil to remain in its optimum range.=0ARemembe
r COKING is the burning of oil.- Keep the oil from burning and there is n
o coking.=0ANo coking equals no valve failure - At least not from coking."
=0A=0ABarry=0A=0AGary is referring to an old SAE paper on sodium exhaust va
lve stems, which may have had an influence on Lycoming changing to their ha
lf inch sodium cooled exhaust valves.- I don't know that they intentional
ly limited the oil to the exhaust guide as that may have been dictated by t
he old automotive lifter design they chose to use years before.=0A=0AAt any
rate there is precious little oil flow to the exhaust rocker area, especia
lly on the RH side of the engine.- Certainly not enough to carry away any
significant amount of heat, but just engouh to coke up the valve stem/guid
e under the right operating conditions.=0A=0AIn all the Tiger engines I hav
e worked on and disassembled the valves from I don't ever recall seeing a s
tuck exhaust valve due to coking.- I think this happens much more often o
n the 150 hp engines and planes that are operated at low throttle settings
for considerable time and at full rich mixture settings.- I think this is
a faily uncommon failure more for a Tiger that is operated at high power a
nd high rpm on x-country flights.- These engines tend to wear out the gui
des and looses up the clearance before they can coke up.=0A=0ASince the sod
ium valves rely on transferring a good deal (maybe a majority) of the heat
up the stem and through the guide to the head for cooling, then this interf
ace is pretty important.- Continental engines transfer heat to the valve
seat as the primary heat path.- Take a look at SKy Ranch Engineering Manu
al by John Schwaner for a detailed discussion of this.=0A=0AThe problem see
ms to be that guide wear is rapid under these conditions of high heat and m
aterial compatibility (hence the HC content guide change) and as the cleara
nce increases the ability to transfer heat to the guide decreases, causing
the valve to run hotter and wear the guide even quicker and fatigue the val
ve.- Eventually the valve head will break off as the valve is weakened an
d hits the seat cockeyed.- Happens all the time if you ignor the wear and
let it go long enough.- Lycoming knows this, hence SB388C.- They have
done little to really solve the problem.=0A=0AI suspect that they may be so
me point where enough oil could be introduced and continuously flowed aroun
d the guide area to extract a significant amount of heat and lower the temp
erature to the point it could not coke up.- How much that would take, who
knows.- I thought that was what Lycoming and Mooney were attempting to d
o on the parallel valve IO-540 engines in the Mooneys which were having ser
ious valve problems on planes that only had 250 hours on them.- Owners we
re not happy.- Gary says that didn't work.- I don't know if that is so
or not.- It would be nice to see the service reports and results after th
e change but that info probably is not available.=0A=0AOne thing is interes
ting is that Bill Marvel has loss of compression, exhaust valve leakage and
wear problems with his old Tiger in time intervals as low as 250 hrs to 40
0 hrs on a routine basis.- He flew the plane entirely on x-country trips
at altitude at 2700 rpm.- Since building his RV-8A with the same engine b
ut with a CS prop operating at 2300 rpm and full throttle he has had no val
ve problems in over 1200 hrs (or maybe more).=0A=0APersonally, I'm not so s
ure that the sodium cooled exhaust valves have not aggravated the guide wea
r problem.- With the HC guides and SB388C the liability risk of an exhaus
t valve failure is reduced and the owner is just left with a low grain head
ache rather than a migraine one!=0A=0AI disassembled a IO-520 Continental e
ngine with 1700 hrs on it (TBO) and found the worst exhaust valve guide had
only about .008" wear.- Cylinder bore wear was barely .003" at the top i
n the choke area.- The choke was gone and the cylinder was now straight,
which according to Chuck Ney is better.- No cylinder work or any other wo
rk besides spark plugs and magneto inspection was ever done on this engine.
- The engine in my Bonanza that was replaced by this one after overhaul w
ent 700 hrs beyond TBO with very few cylinder problems.=0A=0ACliff=0A=0A=0A
==================
Message 13
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| Subject: | Re: Oil Consumption |
I wonder if seals would help?=0A=0A=0A________________________________=0A F
rom: 923TE <923te@att.net>=0ATo: "teamgrumman-list@matronics.com" <teamgrum
man-list@matronics.com> =0ASent: Thursday, February 23, 2012 6:51 AM=0ASubj
ect: Re: TeamGrumman-List: Oil Consumption=0A =0A--> TeamGrumman-List messa
ge posted by: 923TE <923te@att.net>=0A=0ABill Scott says he swaps parts in
the hydraulic lifters to get the greatest clearances allowed by the Lycomin
g specifications. His research shows this parts swapping gets more oil on t
he valve stem. I had him do this on 2 of my engines after reading all their
articles and having my Dad read the articles. Dad thought it was a good id
ea. He worked with sodium filled valves on B-29's and back in the day gaine
d a lot of field knowledge on how to keep them running over the Pacific. I
have often been bothered by the contradictory information. It makes sense t
hat putting any oil on the valve stem would lead to coking if the stem is g
oing to run hot enough to cook the oil. The valve guide material is self lu
bricating and theoretically doesn't need additional oil to work properly.
=0A=0AThe answer Lycoming gives us is to measure "slop" and replace guides.
=0A=0AIt would be great if Lycoming was owned by a huge company that had th
e incentive to develop a better solution. Like these guys=0A=0Ahttp://www.k
omatsu.com/CompanyInfo/profile/report/pdf/152-04_E.pdf=0A=0ANed=0A=0AOn Feb
23, 2012, at 7:24 AM, flyv35b <flyv35b@minetfiber.com> wrote:=0A=0A> --> T
eamGrumman-List message posted by: flyv35b <flyv35b@minetfiber.com>=0A> =0A
> On 2/22/2012 6:32 PM, Gary Vogt wrote:=0A> =0A>>> 30 years ago I called L
ycoming and asked to talk to one of the=0A>>> engineers. I wanted to know w
hich rocker went on which valve. You see,=0A>>> my <700 hr Cheetah had them
one way on one side and the other way on=0A>>> the other side. Both local
AP/IAs didn't know. I eventually talked to=0A>>> 6 engineers. The last one
gave me a phone number for a guy who worked=0A>>> for Lycoming 'in the old
days.' His name was Wayne. Nice guy. He told=0A>>> me about the work done o
n the engines 'in the old days' and told me=0A>>> the correct order for the
rockers. My engine had been assembled wrong=0A>>> at the factory.=0A> =0A>
Bill Marvel had a new engine give to him from Lycoming free of charge beca
use all the intake and exhaust rocker arms were swaped.- They since have
gone to only one part (the previous exhaust rocker with the "squirt" hole)
so that they can't be mixed up.- There is so little oil up there I'm not
sure it makes any difference one way or the other.=0A> =0A> Cliff=0A> =0A>
======================
Message 14
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| Subject: | Re: Oil Consumption |
"Is that how you built your current engine Gary?"=0AJust using factory rock
ers.=0A=0A________________________________=0A From: 923te <923te@att.net>
=0ATo: "teamgrumman-list@matronics.com" <teamgrumman-list@matronics.com>
=0ASent: Thursday, February 23, 2012 7:41 AM=0ASubject: Re: TeamGrumman-Lis
t: Oil Consumption=0A =0A=0ASo all the old farts are dead and now it's our
generation that's the old farts and were supposed to be the experts on 1940
's technology?=0AHmmm=0AWell I'm no expert but I'm thinking that maybe we s
hould go back to what the really old farts were doing when they converted t
he engine for aircraft and just use push rods and rockers with holes in the
m on the intake and NOT the exhaust since the really old farts originally m
ade it-to conduct a dribble of oil ONLY ON THE INTAKE VALVE STEM=0A=0AIs
that how you built your current engine Gary?=0A=0AOn Feb 22, 2012, at 12:35
PM, Gary Vogt <teamgrumman@yahoo.com> wrote:=0A=0A=0AI could give you all
of the references to how to treat sodium filled valves, but then I'd have t
o go against everything Bill and Bill say. -=0A>=0A>=0A>They are wrong.
-Spraying extra oil on the valve stem causes coking on the valves. -Oil
flow to the rocker boxes on an engine with sodium valves is intentionally
limited.=0A>=0A>=0A>The reality is, sodium filled valves do their work by d
irect metal to metal contact. -Or as close to that as possible. -=0A>
=0A>=0A>The intakes could have seals. -The intake (originally) used a dri
bble method to keep oil flow to a minimum. With very little oil on the stem
, very little was sucked in. -=0A>=0A>=0A>The exhaust doesn't need them b
ecause the pressure pushes exhaust gases up the stem. -What little oil is
squirted by the rocker is just enough to keep the stem lubricated. -=0A>
=0A>=0A>Lycoming had a knee jerk reaction to the valves in a Mooney. -It
doesn't help. -Their research consisted of a corporate meeting. -Had th
at corporate decision not been a waste of manpower, time, and money, all ne
w engines would have the retro fit.=0A>=0A>=0A>30 years ago I called Lycomi
ng and asked to talk to one of the engineers. -I wanted to know which roc
ker went on which valve. -You see, my <700 hr Cheetah had them one way on
one side and the other way on the other side. -Both local AP/IAs didn't
know. -I eventually talked to 6 engineers. -The last one gave me a phon
e number for a guy who worked for Lycoming 'in the old days.' -His name w
as Wayne. -Nice guy. -He told me about the work done on the engines-'
in the old days'-and told me the correct order for the rockers. -My eng
ine had been assembled wrong at the factory.=0A>=0A>=0A>=0A>_______________
_________________=0A> From: 923te <923te@att.net>=0A>To: teamgrumman-list@m
atronics.com =0A>Sent: Wednesday, February 22, 2012 9:24 AM=0A>Subject: Re:
TeamGrumman-List: Oil Consumption=0A> =0A>=0A> =0A>Bill Marvel and Bill Sc
ott make for some very interesting reading and have =0Aa very strong argume
nt in the following articles:=0A>http://egaa.home.mindspring.com/valves.htm
l=0A>-=0A>Especially this article:=0A>http://egaa.home.mindspring.com/eng
ine2.htm=0A>about the Lycoming-TIO-540-AF1A Oil Cooled Exhaust Valve Guid
e =0AKit=0A>-=0A>Their arguments seem to be verified by what Lycoming did
to cool the =0Aexhaust valves with more oil flow onto the stems.=0A>-=0A
>I agree that the valve stem seals certainly go =0Acounter to trying to coo
l them. =0A>I guess it just depends on what you are trying =0Ato do. It's a
catch 22 isn't it?=0A>-=0A>Sure would be great to see some R&D by =0ALyc
olming on these issues. =0A>----- Original Message ----- =0A>>From: Gary V
ogt =0A>>To: teamgrumman-list@matronics.com =0A>>Sent: Tuesday, February 21
, 2012 12:37 PM=0A>>Subject: Re: TeamGrumman-List: Oil Consumption=0A>>
=0A>>=0A>>Kinda makes that whole 'squirting oil at the valve stem' seem sil
ly now. -Not enough exposed to do any extra cooling.=0A>>=0A>>=0A>>=0A>>
________________________________=0A>> From: 923TE <923te@att.net>=0A>>To: "
teamgrumman-list@matronics.com" <teamgrumman-list@matronics.com> =0A>>Sent
: Tuesday, February 21, 2012 8:16 AM=0A>>Subject: Re: TeamGrumman-List: O
il Consumption=0A>>=0A>>Yes I would be most =0A interested in sealing the
intake valves but the certified Continentals seal =0A both and the RV guys
that are into this have sealed both. I hear that Lycon =0A even machines
the guide to fit a seal on it.=0A>>=0A>>Apparently with Gapless =0A rings,
you suck a lot more oil so they started using the seals=0A>>Check it out
=0A here:=0A>>=0A>>http://www.vansairforce.com/community/showthread.php?t
=69483&highlight=Gapless+rings+seals&page=2=0A>>=0A>>http://www.vansa
irforce.com/community/showthread.php?t=56297&highlight=Gapless+rings+se
als=0A>>=0A>>See =0A the red seal?=0A>>=0A>>=0A>>=0A>>=0A>>=0A>>Ned=0A>>
=0A>><><=0A>>=0A>>On =0A Feb 21, 2012, at 7:36 AM, flyv35b <flyv35b@minetf
b <flyv35b@minetfiber.com>=0A>>> =0A>>> On 2/20/2012 6:47 PM, Gary Vogt wro
te:=0A>>>> Seals won't work =0A on sodium filled valves. These guides are
designed to=0A>>>> be run with =0A a minimum clearance.=0A>>> =0A>>> Of co
urse.- I think he meant the =0A intake valves, where they would work.=0A
>>> =0A>>> =0A>>> =0A>>> =0A>>=0A>><pre><b><font size=3D2 color="#00000
0" face=3D"courier =0A 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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=3D=3D=3D=3D=3D= =0A --> <a href=3D"http://www.matronics.com
/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman
-List&D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
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3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=0A>>=0A>></b></fo
nt></pre>=0A>>=0A>>=0A>http://www.matronics.com/Navitarget=
"_blank" href="http://forums.matronics.com">http://forums.matron--> =
==========0A-List">http://www.matronics.com/Navigator?Tea
mGrumman-List ====================
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orums.matronics.com=0A=================
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cs.com/contribution">http://www.matronics.com/contribution=0A====
=========================0A
=======================
Message 15
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| Subject: | Re: Oil Consumption |
Gary:
Thanks for the obscure post & website address. But come on- - - Anyone
else find anything on Sam Heron? And what does this have to do with 'more
oil won't help!' That article is only a history that Sam came up with the
idea of sodium filled valves - Way back in 1916. It does not shed light on
today with the same problem they had in 1916.
You would have thunk they would have learned from then to now... But, then
again it is the lawyers that run engine companies - Not Engineers.
Barry
On Thu, Feb 23, 2012 at 12:51 PM, Gary Vogt <teamgrumman@yahoo.com> wrote:
> The guides on sodium filled valves are supposed to be tight. Not sloppy.
>
> Material change (guide) was to reduce wear and keep the clearance tight.
> Material change (valve) was for wear. Lead is a lubricant. Take out the
> lead, you need a better valve.
>
> I can't believe you can't find a reference to Sam Heron.
>
> here is one reference. I'm not going to do your homework.
> http://www.agelessengines.com/j5.htm
>
>
> ------------------------------
> *From:* FLYaDIVE <flyadive@gmail.com>
> *To:* teamgrumman-list@matronics.com
> *Sent:* Thursday, February 23, 2012 12:56 AM
>
> *Subject:* Re: TeamGrumman-List: Oil Consumption
>
> Gary:
>
> I looked up Sam Heron and could not find anything. Can you post a link?
>
> IF - IF - The cooling is kept to a minimum to allow heat transfer someone
> has been feeding the industry a HUGE BLIVIT. It makes better sense to keep
> the valve and guide clearance to a minimum to control valve and guide wear.
> YOU DO NOT WANT THE VALVE SLOPPY AND FLOPPING AROUND. Think of SB-388!!!
> AND if you want to take the path that the heat is mainly or REQUIRED to
> be transferred through the Valve Head and Seat- That is true and all well
> and good, BUT... What do you think would happen if the valve head LOOSES
> contact surface because of SLOP between the valve guide and stem due to a
> larger SLOPPY fit?
> AND what about the change in material of the valve seat years ago to
> better handle the heat?
> AND there was a change in the valve guide material as well. Maybe not to
> handle the heat transfer - But, to handle the ware. And where does ware
> come from?
> No, I would not change the tolerance between valve stem and guide. I
> would just REMOVE as much heat as possible while allowing two actions to
> take place:
> 1 - The material coefficient to keep the valve and guide tolerances.
> 2 - The oil to remain in its optimum range.
> Remember COKING is the burning of oil. Keep the oil from burning and
> there is no coking.
> No coking equals no valve failure - At least not from coking.
>
> Barry
> ============================
>
>
> On Wed, Feb 22, 2012 at 10:38 PM, Gary Vogt <teamgrumman@yahoo.com> wrote:
>
> Look up the original work by Sam Heron. The oil does not do the cooling.
> At all. You only want a minimum of oil on the valve stems for
> lubrication. If you're flooding the stem with oil, some will get into the
> guide and the heat will cook it. In sodium filled valves, the cooling is
> done through the valve seat and valve guide.
>
> Sodium filled valves are used in a lot of top fuel dragsters. For a
> reason.
>
> ------------------------------
> *From:* FLYaDIVE <flyadive@gmail.com>
> *To:* teamgrumman-list@matronics.com
> *Sent:* Wednesday, February 22, 2012 6:59 PM
>
> *Subject:* Re: TeamGrumman-List: Oil Consumption
>
> Gary said:
> They are wrong. Spraying extra oil on the valve stem causes coking on the
> valves. Oil flow to the rocker boxes on an engine with sodium valves is
> intentionally limited.
>
> The reality is, sodium filled valves do their work by direct metal to
> metal contact. Or as close to that as possible.
>
>
> Gary:
>
> Now that does not make sense. I don't think anyone is around that was
> involved in the original design of the Lycoming engine. The idea of a
> sodium filled valve and the extra transfer of heat because of the sodium is
> feasible but has proven short of goal. Our problem has always been over
> heating of the exhaust valve and coking on the stem of that valve.
> Continental uses solid stem valves and their failure mode is the same as
> Lycoming. There is no way of collecting data as to how many Lycoming and
> Continental valve failures there are.
> BUT! Isn't it COKING on the valve that causes the problem? AND... What
> is COKING? Coking is the BURNING of OIL with the subsequent build up
> that causes the valve to stick. When they stick in the DOWN position the
> piston comes up to smash the valve head and bend the valve shank.
> SO! HOW WOULD ONE PREVENT THE COKING?
> BY LOWERING THE TEMPERATURE THAT CAUSES THE COKING.
> AND HOW WOULD ONE DO THAT?
> BY INCREASING THE COOLING BY INCREASING THE OIL FLOW OVER THE VALVE STEM.
> No, I'm not yelling, just emphasing the point.
>
> Now, if this does not make sense, please explain why. I cannot accept the
> idea that minimal oil for heat transfer is the way to go or the intent.
>
> Barry
>
> Here are my thoughts:
> No mater how good or bad the heat transfer is between metal to meatal
> (something OIL is the medium that carries the heat away.
>
>
> *http://www.matronics.com/Navigator?TeamGrumma====================
> *
>
>
> *
>
> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-List
> tp://forums.matronics.com
> _blank">http://www.matronics.com/contribution
> *
>
>
> *http://www.matronics.com/Navigator?TeamGruank" href="http://forums.matronics.com">http://forums.matronics.com rel="nofollow" target="_blank" href="http://www.matronics.com/contri==
> *
>
>
> *
>
> *
>
>
Message 16
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| Subject: | Re: Oil Consumption |
I found an obscure paper written by Heron many years ago. -Come on Barry,
get creative and find.=0A=0A=0A________________________________=0A From: F
LYaDIVE <flyadive@gmail.com>=0ATo: teamgrumman-list@matronics.com =0ASent:
Thursday, February 23, 2012 10:26 AM=0ASubject: Re: TeamGrumman-List: Oil C
onsumption=0A =0A=0AGary:=0A=0AThanks for the obscure post & website addres
s. -But come on- - - Anyone else find anything on Sam Heron? -And what
does this have to do with 'more oil won't help!' -That article is only a
history that Sam came up with the idea of sodium filled valves - Way back i
n 1916. -It does not shed light on today with the same problem they had i
n 1916.=0AYou would have thunk they would have learned from then to now...
-But, then again it is the lawyers that run engine companies - Not Engine
ers.=0A=0ABarry=0A=0A=0A=0A=0AOn Thu, Feb 23, 2012 at 12:51 PM, Gary Vogt <
teamgrumman@yahoo.com> wrote:=0A=0AThe guides on sodium filled valves are s
upposed to be tight. -Not sloppy.=0A>=0A>=0A>Material change (guide) was
to reduce wear and keep the clearance tight.=0A>Material change (valve) was
for wear. -Lead is a lubricant. -Take out the lead, you need a better
valve.=0A>=0A>=0A>I can't believe you can't find a reference to Sam Heron.
=0A>=0A>=0A>here is one reference. -I'm not going to do your homework.=0A
>http://www.agelessengines.com/j5.htm=0A>=0A>=0A>=0A>=0A>=0A>=0A>__________
______________________=0A> From: FLYaDIVE <flyadive@gmail.com>=0A>To: teamg
rumman-list@matronics.com =0A>Sent: Thursday, February 23, 2012 12:56 AM=0A
>=0A>Subject: Re: TeamGrumman-List: Oil Consumption=0A> =0A>=0A>Gary:=0A>
=0A>=0A>I looked up Sam Heron and could not find anything. -Can you post
a link?=0A>=0A>=0A>IF - IF - The cooling is kept to a-minimum-to allow
heat transfer someone has been feeding the industry a HUGE BLIVIT. -It ma
kes better sense to keep the valve and guide clearance to a minimum to cont
rol valve and guide wear. -YOU DO NOT WANT THE VALVE SLOPPY AND FLOPPING
AROUND. -Think of SB-388!!! -AND if you want to take the path that the
heat is mainly or REQUIRED to be-transferred-through the Valve Head and
Seat- That is true and all well and good, BUT... What do you think would h
appen if the valve head LOOSES contact surface because of SLOP between the
valve guide and stem due to a larger SLOPPY fit? -=0A>AND what about the
change in material of the valve seat years ago to better handle the heat?
=0A>AND there was a change in the valve guide material as well. -Maybe no
t to handle the heat transfer - But, to handle the ware. And where does war
e come from? -=0A>No, I would not change the tolerance between valve stem
and guide. -I would just REMOVE as much heat as-possible while allowin
g two actions to take place:=0A>1 - The material-coefficient-to keep th
e valve and guide tolerances.=0A>2 - The oil to remain in its-optimum-r
ange.=0A>Remember COKING is the burning of oil. -Keep the oil from burnin
g and there is no coking.=0A>No coking equals no valve failure - At least n
ot from coking.=0A>=0A>=0A>Barry=0A>=============
=================0A>=0A>=0A>=0A>=0A>=0A>=0A
>=0A>On Wed, Feb 22, 2012 at 10:38 PM, Gary Vogt <teamgrumman@yahoo.com> wr
ote:=0A>=0A>Look up the original work by Sam Heron. -The oil does not do
the cooling. -At all. -You only want a minimum of oil on the valve stem
s for lubrication. -If you're flooding the stem with oil, some will get i
nto the guide and the heat will cook it. -In sodium filled valves, the co
oling is done through the valve seat and valve guide.=0A>>=0A>>=0A>>Sodium
filled valves are used in a lot of top fuel dragsters. -For a reason.=0A>
>=0A>>=0A>>=0A>>________________________________=0A>> From: FLYaDIVE <flyad
ive@gmail.com>=0A>>To: teamgrumman-list@matronics.com =0A>>Sent: Wednesday,
February 22, 2012 6:59 PM=0A>>=0A>>Subject: Re: TeamGrumman-List: Oil Cons
umption=0A>> =0A>>=0A>>Gary said:=0A>>>They are wrong. -Spraying extra oi
l on the valve stem causes coking on the valves. -Oil flow to the rocker
boxes on an engine with sodium valves is intentionally limited.=0A>>>=0A>>>
=0A>>>The reality is, sodium filled valves do their work by direct metal to
metal contact. -Or as close to that as possible.-=0A>>=0A>>=0A>>Gary:
=0A>>=0A>>=0A>>Now that does not make sense. -I don't think anyone is aro
und that was involved in the-original-design of the Lycoming engine.
-The idea of a sodium filled valve and the extra transfer of heat because
of the sodium is-feasible-but has proven short of goal. -Our problem
has always been over heating of the exhaust valve and coking on the stem o
f that valve. -Continental-uses solid stem valves and their failure mod
e is the same as Lycoming. - There is no way of collecting data as to how
many Lycoming and Continental valve failures there are.=0A>>BUT! -Isn't
it COKING on the valve that causes the problem? -AND... What is COKING?
-Coking is the BURNING of OIL with the-subsequent build up that causes
the valve to stick. -When they stick in the DOWN position the piston come
s up to smash the valve head and bend the valve shank.=0A>>SO! -HOW WOULD
ONE PREVENT THE COKING? -=0A>>BY LOWERING THE TEMPERATURE THAT CAUSES TH
E COKING.=0A>>AND HOW WOULD ONE DO THAT?=0A>>BY INCREASING THE COOLING BY I
NCREASING THE OIL FLOW OVER THE VALVE STEM. -No, I'm not yelling, just-
emphasing-the point.=0A>>-=0A>>Now, if this does not make sense, please
explain why. -I cannot accept the idea that-minimal-oil for heat tra
nsfer is the way to go or the intent.=0A>>=0A>>=0A>>Barry=0A>>=0A>>=0A>>Her
e are my thoughts:=0A>>No mater how good or bad the heat transfer is betwee
n metal to meatal (something OIL is the medium that carries the heat away.
=0A>>=0A>>=0A>>=0A>>=0A>>http://www.matronics.com/Navigator?TeamGrumma=
==================== =0A>>=0A>>=0A>
>st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-List
tp://forums.matronics.com _blank">http://www.matronics.com/contribution =0A
>=0A>http://www.matronics.com/Navigator?TeamGruank" href="http://forums.m
atronics.com">http://forums.matronics.com rel="nofollow" target="_blank
" href="http://www.matronics.com/contri=== =0A>=0A>=0A>st" target
="_blank">http://www.matronics.com/Navigator?TeamGrumman-List=0Atp://foru
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