Today's Message Index:
----------------------
1. 05:33 AM - Re: Re: looking for help with "mushy" brakes on CJ (Gary Gabbard)
2. 07:02 AM - Re: Staking a Housai exhaust valve (or M-14) (Bitterlich, Mark G CIV NAVAIR, WD)
3. 08:59 AM - Re: Staking a Housai exhaust valve (or M-14) (Mark Davis)
4. 10:18 AM - Re: Staking a Housai exhaust valve (or M-14) (keithmckinley)
5. 10:49 AM - Re: Re: looking for help with "mushy" brakes on CJ (jblake207@comcast.net)
6. 01:32 PM - Re: Re: Staking a Housai exhaust valve (or M-14) (Mark Davis)
7. 02:15 PM - Air Compressor (?) Issue (Jill Gernetzke)
8. 03:23 PM - Re: Air Compressor (?) Issue (Jay Land)
9. 05:41 PM - Re: Air Compressor (?) Issue (Frank Stelwagon)
10. 07:18 PM - Re: Air Compressor (?) Issue (Roger Kemp M.D.)
11. 07:39 PM - Re: Air Compressor (?) Issue (keithmckinley)
12. 07:48 PM - Re: Staking a Housai exhaust valve (or M-14) (keithmckinley)
13. 08:35 PM - Re: Re: Staking a Housai exhaust valve (or M-14) (Roger Kemp M.D.)
14. 08:54 PM - Re: Air Compressor (?) Issue (Vic)
15. 11:42 PM - Re: Air Compressor (?) Issue (Jan Mevis)
Message 1
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| Subject: | Re: looking for help with "mushy" brakes on CJ |
Guys on my cable the strands of the cable had worn so much inside the outer h
ousing that several of the strands were broken and only one strand was actua
ting the brakes. A few more applications of the brakes and I would have had n
o brakes. They were broken inside the housing where you can not see to cable
. Don't screw around with it, CHANGE THE CABLE!!!! CJ N
22YK. Gary G.
Sent from my iPad
> On Oct 14, 2013, at 9:54, doug sapp <dougsappllc@gmail.com> wrote:
>
> Guy's, cable stretch to the degree that it would effect your brakes is a "
wives tale". The cable is not stretching, your swedge might be slipping or t
he gob/ball of solder (on the stock cable) might be giving way, but the cabl
e is not stretching. I would estimate that 75% of the guys who adjusted the
ir cables because of "stretch" had the cable break soon after the adjustment
.
>
>
>
>
>> On Mon, Oct 14, 2013 at 5:43 AM, keithmckinley <cetopfed@gmail.com> wrote
:
>>
>> Hi Sam and Doc,
>>
>> It is my feeling that the differential and proportioner are in good shape
. The cable is no doubt an original Chinese cable that I believe has stretch
ed some. Good news is I do have SS cable from Doug in stock.
>>
>> I may try the adjustment the retaining nut, but there is not much left on
it
>>
>> Keith
>>
>> --------
>> Keith McKinley
>> 700HS
>> X26 Sebastian, FL
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=410488#410488
>>
>>
>>
>>
>>
>>
>>
>> ==========
>> rget="_blank">http://www.matronics.com/Navigator?Yak-List
>> ==========
>> http://forums.matronics.com
>> ==========
>> le, List Admin.
>> ="_blank">http://www.matronics.com/contribution
>> ==========
>
>
>
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>
Message 2
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| Subject: | Staking a Housai exhaust valve (or M-14) |
Not trying to shoot you Gary, but I would like to know what you consider a "reliable
source" to be.
I have used both multi-weight and single weight oils. I found the single weight
to be a real pain in the tail, especially in anything less than HOT weather.
50 weight just did not want to drain out of the intake drain kit, and with a
tail dragger (YAK-50) that is a serious problem as oil left in the intakes can
get "gulped in" and that is bad ju-ju. Some folks using their airplanes (primarily)
for really hard aerobatics switch to single weight in an attempt to cut
down on consumption, etc. The concept being that thicker oil is less likely
to creep past piston rings in the short term. Probably has some basis in fact
because the Russian piston rings leak like crazy when they are cold anyway,
but I doubt there has been any real study done on how effective that might be
for contributing to valves sticking.
That said, after that experience I have used Phillips Multi Weight Radial Engine
Oil (20-60W) with great success for many hundreds of hours. During that time,
I have had to pull just one cylinder for a sticking exhaust valve and that
was soon after I purchased the aircraft.
Just FYI, sticking exhaust valves are typically caused by lead deposits and not
oil. That was true in my case, and was in my opinion caused by me running the
engine at 60-70% and letting it get too cool resulting in lead precipitation
onto the valve. My M-14 does not have shutters by the way, so running it that
low caused it to have cylinder head temps down in the "yellow" range. Increasing
the normal operating RPM to get cylinder head temps up, and adding MMO to
the fuel ended the sticking exhaust valve issue.
Over the next 700 hours following that, I have had to stake one valve, and that
procedure worked.
I am writing all of this because I want folks to be very cautious considering things
to do to their airplane that come from a "reliable source". Many things
have been recommended in the same fashion over the years, one of the best known
being squirting air tool oil into the pneumatic system. Something in my ignorance
I actually went ahead and tried, followed shortly there-after by total
failure of both landing gear actuator chevron seals. Luckily I avoided a gear
up landing.
Making a decision on whether to run a single or multi weight oil is based on many
factors, but I would consider the least of them to be "preventing valves sticking".
And the reliable source in this particular case is myself. :-=)
Mark Bitterlich
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gary Gabbard
Sent: Monday, October 14, 2013 15:03
Subject: Re: Yak-List: Staking a Housai exhaust valve (or M-14)
This is some info I was supplied with from a reliable source. What type of oil
are you using? It has been observed that there is a valve sticking problem with
multi grade oils. Not sure what brand. It has been a couple of years since
I got the info. But the suggestion that straight grade oils have not been having
the problem. I know there will be people with different personal opinions.
I am just the messenger. Don't try to shoot me. Won't do any good. Gary
G. CJ. N22YK
Sent from my iPhone
On Oct 14, 2013, at 10:49, Robin Hou <rmhou@yahoo.com> wrote:
I had a sticky valve in #5 that staking did not help. Filling the cylinder head
with MMO for a few nights cured it. It has been about 20 hours since the MMO
treatment and it is still running well. Last conditional inspection a month ago
#5 read in the mid-70's, so I was pleased.
________________________________
From: keithmckinley <cetopfed@gmail.com>
To: yak-list@matronics.com
Sent: Monday, October 14, 2013 6:56 AM
Subject: Yak-List: Staking a Housai exhaust valve (or M-14)
Anyone that has done this... can you share your "gotchas"
Keith
--------
Keith McKinley
700HS
X26 Sebastian, FL
Read this topic online here:
http://forums.matronics.com/viewtosp; =======================
D============================================
ist"">http://www.matronics.com/Navigator?Yak-List
D============================================
//forums.matronics.com
D============================================
ot;">http://www.matronics.com/contribution
D============================================
Message 3
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| Subject: | Re: Staking a Housai exhaust valve (or M-14) |
Mark,
I've had the same experience with sticking valves, two of which
wouldn't stake and required the jugs being replaced with spares I had. Both
happened while running X/C 25W60, with MMO and either Decalin or TCP in the
fuel. I had been adding MMO to the oil only immediately prior to an oil
change, flying it for 30 minutes to warm it up and draining the oil while
hot. I don't run an oil filter, but never run the oil past 25 hours. Since
my last cylinder replacement 18 months ago, I've been running MMO per Jill's
recommendation in the oil continuously and haven't had a problem
since....knock on wood. I run half the recommended amount in hot summer
months and a full dose in winter months. I occasionally fly in very cold
temps in the winter time, which may have aggravated the lead accumulation as
you suggested. Sometimes running with the gills full closed at cruise is
necessary to keep the cylinders warm enough to scavenge a little heat for my
cold blooded wife in the back seat! I mix the MMO in with the new Phillips
in the 2.5 gallon jug so I don't have to do the higher level math to add the
right amount every time I add oil. My engine is approaching 900 hrs and I
believe it may be using just a bit more oil due to the thinning by the MMO,
but it's cheaper than replacing cylinders. As they say, YMMV.
Mark Davis
N44YK
----- Original Message -----
From: "Bitterlich, Mark G CIV NAVAIR, WD" <mark.bitterlich@navy.mil>
Sent: Tuesday, October 15, 2013 7:58 AM
Subject: RE: Yak-List: Staking a Housai exhaust valve (or M-14)
> <mark.bitterlich@navy.mil>
>
> Not trying to shoot you Gary, but I would like to know what you consider a
> "reliable source" to be.
>
> I have used both multi-weight and single weight oils. I found the single
> weight to be a real pain in the tail, especially in anything less than HOT
> weather. 50 weight just did not want to drain out of the intake drain
> kit, and with a tail dragger (YAK-50) that is a serious problem as oil
> left in the intakes can get "gulped in" and that is bad ju-ju. Some folks
> using their airplanes (primarily) for really hard aerobatics switch to
> single weight in an attempt to cut down on consumption, etc. The concept
> being that thicker oil is less likely to creep past piston rings in the
> short term. Probably has some basis in fact because the Russian piston
> rings leak like crazy when they are cold anyway, but I doubt there has
> been any real study done on how effective that might be for contributing
> to valves sticking.
>
> That said, after that experience I have used Phillips Multi Weight Radial
> Engine Oil (20-60W) with great success for many hundreds of hours. During
> that time, I have had to pull just one cylinder for a sticking exhaust
> valve and that was soon after I purchased the aircraft.
>
> Just FYI, sticking exhaust valves are typically caused by lead deposits
> and not oil. That was true in my case, and was in my opinion caused by me
> running the engine at 60-70% and letting it get too cool resulting in lead
> precipitation onto the valve. My M-14 does not have shutters by the way,
> so running it that low caused it to have cylinder head temps down in the
> "yellow" range. Increasing the normal operating RPM to get cylinder head
> temps up, and adding MMO to the fuel ended the sticking exhaust valve
> issue.
>
> Over the next 700 hours following that, I have had to stake one valve, and
> that procedure worked.
>
> I am writing all of this because I want folks to be very cautious
> considering things to do to their airplane that come from a "reliable
> source". Many things have been recommended in the same fashion over the
> years, one of the best known being squirting air tool oil into the
> pneumatic system. Something in my ignorance I actually went ahead and
> tried, followed shortly there-after by total failure of both landing gear
> actuator chevron seals. Luckily I avoided a gear up landing.
>
> Making a decision on whether to run a single or multi weight oil is based
> on many factors, but I would consider the least of them to be "preventing
> valves sticking".
>
> And the reliable source in this particular case is myself. :-=)
>
> Mark Bitterlich
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com
> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gary Gabbard
> Sent: Monday, October 14, 2013 15:03
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Staking a Housai exhaust valve (or M-14)
>
> This is some info I was supplied with from a reliable source. What type of
> oil are you using? It has been observed that there is a valve sticking
> problem with multi grade oils. Not sure what brand. It has been a couple
> of years since I got the info. But the suggestion that straight grade oils
> have not been having the problem. I know there will be people with
> different personal opinions. I am just the messenger. Don't try to shoot
> me. Won't do any good. Gary G. CJ. N22YK
>
> Sent from my iPhone
>
> On Oct 14, 2013, at 10:49, Robin Hou <rmhou@yahoo.com> wrote:
>
>
> I had a sticky valve in #5 that staking did not help. Filling the cylinder
> head with MMO for a few nights cured it. It has been about 20 hours since
> the MMO treatment and it is still running well. Last conditional
> inspection a month ago #5 read in the mid-70's, so I was pleased.
>
> ________________________________
>
> From: keithmckinley <cetopfed@gmail.com>
> To: yak-list@matronics.com
> Sent: Monday, October 14, 2013 6:56 AM
> Subject: Yak-List: Staking a Housai exhaust valve (or M-14)
>
>
>
> Anyone that has done this... can you share your "gotchas"
>
> Keith
>
> --------
> Keith McKinley
> 700HS
> X26 Sebastian, FL
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtosp; =======================
>
>
> D============================================
> ist"">http://www.matronics.com/Navigator?Yak-List
> D============================================
> //forums.matronics.com
> D============================================
> ot;">http://www.matronics.com/contribution
> D============================================
>
>
>
Message 4
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| Subject: | Re: Staking a Housai exhaust valve (or M-14) |
I religiously use 2 oz/ 5 gal in my fuel but have never put it in the oil. DO you
use the same dilution ratio?
K
--------
Keith McKinley
700HS
X26 Sebastian, FL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=410628#410628
Message 5
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| Subject: | Re: looking for help with "mushy" brakes on CJ |
I would strongly suggest that you replace the old =C2-brake cable and hou
sing.=C2- It is the single point of failure in the brake =C2-system...
it fails and you're SOL.=C2- My cable broke while I was taxing and I inst
antly realized that the only option I had, since no one was in the back sea
t, was to kill the mags and hope for the best.=C2- Fortunately, the airpl
ane rolled to a stop a few feet from another airplane.=C2- I went to a lo
cal motorcycle shop and bought a new cable and housing (I think it was actu
ally a throttle cable for an ATV) that fit perfectly.=C2- I now squirt a
little oil in it each year and so far no signs of wear or stretch.=C2- Mu
ch better solution than trying to swag an end to a new cable and =C2-then
trying to route that through the old housing.=C2- Or maybe Doug has the
perfect replacement.
Jon Blake
jblake207@comcast.net
----- Original Message -----
From: "Gary Gabbard" <ggg6@att.net>
Sent: Monday, October 14, 2013 9:47:53 AM
Subject: Re: Yak-List: Re: looking for help with "mushy" brakes on CJ
Several years ago I had the same brake problem found the old cable was comi
ng apart inside of the outer covering. Don't mess with adjustment. Install
the replacement cable. Or you might get a nasty surprise. =C2-Made a new
inside cable =C2- I think that was before anyone was selling replacement
parts. =C2-Gary G. =C2-CJ. N22YK
Sent from my iPhone
> On Oct 14, 2013, at 5:43, "keithmckinley" <cetopfed@gmail.com> wrote:
>
>
> Hi Sam and Doc,
>
> It is my feeling that the differential and proportioner are in good shape
. The cable is no doubt an original Chinese cable that I believe has stretc
hed some. Good news is I do have SS cable from Doug in stock.
>
> I may try the adjustment the retaining nut, but there is not much left on
it
>
> Keith
>
> --------
> Keith McKinley
> 700HS
> X26 Sebastian, FL
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=410488#410488
>
>
>
>
>
>
>
>
>
>
===========
===========
MS -
===========
e -
=C2- =C2- =C2- =C2- =C2--Matt Dralle, List Admin.
===========
Message 6
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| Subject: | Re: Staking a Housai exhaust valve (or M-14) |
Keith,
I add it at the rate recommended on the label in the cold months and
cut it in half in the summer. Just my personal choice to not dilute the oil
so much in high temps when I know the oil temp may be nudging the red arc.
Mark
----- Original Message -----
From: "keithmckinley" <cetopfed@gmail.com>
Sent: Tuesday, October 15, 2013 11:13 AM
Subject: Yak-List: Re: Staking a Housai exhaust valve (or M-14)
>
> I religiously use 2 oz/ 5 gal in my fuel but have never put it in the oil.
> DO you use the same dilution ratio?
>
> K
>
> --------
> Keith McKinley
> 700HS
> X26 Sebastian, FL
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=410628#410628
>
>
>
Message 7
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| Subject: | Air Compressor (?) Issue |
Group,
We have met up with a head scratcher. I am throwing it out to the group to
chew on:
The Yak 52 owner purchased his aircraft on an insurance sale. The aircraft
had been totaled because of an engine fire. Attempts to talk to the
original owners and learn more about the aircraft's history have been
unsuccessful. Originally, we were contacted because the air system was not
building pressure. A photo sent by the owner, elicited a remark by me that
there seemed to be a lot of oil in the banjo/outlet valve fitting. The
compressor itself was very dirty.
The owner cleaned the outlet valve with no appreciable change in output.
He then bought a "NOS" comp from a private party, installed it and it
failed in 2.5 hours. This compressor had actually been overhauled by us in
2006. The nuts stripped off of the 4 studs on the bottom end of the
compressor (green case), allowing the top end off the compressor to hammer
up and down. Oil was all over the back end of the engine.
The customer then sent his original compressor for overhaul and run on our
test bench. He installed this overhauled compressor and it failed after 40
minutes in flight. This time the 4 studs sheared off of the bottom end of
the compressor.
He sent us both failed compressors, the drive and drive gear, shear
coupling, the FT-1 "snot" valve and the pressure relief tee setup. We
built one compressor out of the two failed units. The 4 stripped studs were
replaced with new studs and installed with Loctite. The compressor was test
run and produced 925 psi. The pressure relief valve tee setup was tested -
it relieved normally - rebuilt with a new piston, new seals in the one way
checkvalves and the pressure set to 50 atm. (The pressure relief valve had a
Teflon seal which was in very poor condition.) The snot valve was tested,
flushed and retested. The compressor, gaskets and drive unit were secured
to one another in the proper alignment for the reinstall.
The air compressor was returned to the customer and it was reinstalled
without attaching the steel air line. Everything was normal for about 1.5
hours of ground runs.
A flight was completed with the steel coiled air line still not attached.
The flight was normal.
The steel line was reattached and 90 minutes of ground run time. He noticed
that pressure was not building as it should and opened the cowling to find
one of the 4 hold-down nuts backing off. He also reported that the other 3
nuts were not tight. The owner drilled and safety wired the nuts.
(Note: There is a CRITICAL clearance that is set between the bottom of the
Stage I piston and the top of the Stage II cylinder. Over-tightening these
nuts will cause the top of the piston to hit the top of the Stage II
cylinder. Too much clearance and it bottoms out on the other end.)
We received the compressor and installed new studs and steel locknuts with
Loctite. The compressor has been returned but not run, yet.
Here is what we know:
1. The FT-1 Snot valve is was flushed and functioning properly.
2. The pressure relief valve tee and checkvalves were all tested and
the system functioned normally on a bench test, with the pressure relief
valve popping off at 750 psi.
3. A new steel line was provided to the customer, but I do not know if
this was installed.
4. On the 4th installation of the compressor, we returned the
compressor, shear coupling, drive pad and gear tie-wrapped as a unit for
correct clocking. We received photo verification that the compressor drive
was installed correctly.
5. The compressor operated normally on the last run until the steel
line was attached to it. Then, 1 nut backed off and the other 3 were
reported loose. Hence, we replaced the hex nuts/lockwashers with steel
locknuts in case the lockwashers had failed and that was the only problem on
the last run.
6. The force to shear the compressor studs is in excess of 22,000 lbs.
7. The shear coupling appears to be a factory unit. A new one was
sent to the customer, but returned back to me.
8. The oil return holes in the accessory case are large and not
plugged.
In the 20+ years that we have been overhauling air compressors, we have
never encountered this problem. Please use this problem as your own
theoretical and reasoning challenge to put forth real possibilities
-grasping at unicorns, rainbows or butterflies not allowed. : )
Jill
M-14P, Inc.
Message 8
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| Subject: | Re: Air Compressor (?) Issue |
It needs some MMO.........;)
On 10/15/13 5:09 PM, "Jill Gernetzke" <jill@m-14p.com> wrote:
Group,
We have met up with a head scratcher. I am throwing it out to the group to
chew on:
The Yak 52 owner purchased his aircraft on an insurance sale. The aircraft
had been totaled because of an engine fire. Attempts to talk to the origi
nal owners and learn more about the aircraft's history have been unsuccessf
ul. Originally, we were contacted because the air system was not building
pressure. A photo sent by the owner, elicited a remark by me that there se
emed to be a lot of oil in the banjo/outlet valve fitting. The compressor
itself was very dirty.
The owner cleaned the outlet valve with no appreciable change in output.
He then bought a "NOS" comp from a private party, installed it and it fail
ed in 2.5 hours. This compressor had actually been overhauled by us in 200
6. The nuts stripped off of the 4 studs on the bottom end of the compresso
r (green case), allowing the top end off the compressor to hammer up and do
wn. Oil was all over the back end of the engine.
The customer then sent his original compressor for overhaul and run on our
test bench. He installed this overhauled compressor and it failed after 40
minutes in flight. This time the 4 studs sheared off of the bottom end of
the compressor.
He sent us both failed compressors, the drive and drive gear, shear couplin
g, the FT-1 "snot" valve and the pressure relief tee setup. We built one
compressor out of the two failed units. The 4 stripped studs were replaced
with new studs and installed with Loctite. The compressor was test run an
d produced 925 psi. The pressure relief valve tee setup was tested - it re
lieved normally - rebuilt with a new piston, new seals in the one way chec
kvalves and the pressure set to 50 atm. (The pressure relief valve had a Te
flon seal which was in very poor condition.) The snot valve was tested, flu
shed and retested. The compressor, gaskets and drive unit were secured to
one another in the proper alignment for the reinstall.
The air compressor was returned to the customer and it was reinstalled with
out attaching the steel air line. Everything was normal for about 1.5 hours
of ground runs.
A flight was completed with the steel coiled air line still not attached.
The flight was normal.
The steel line was reattached and 90 minutes of ground run time. He notice
d that pressure was not building as it should and opened the cowling to fi
nd one of the 4 hold-down nuts backing off. He also reported that the other
3 nuts were not tight. The owner drilled and safety wired the nuts.
(Note: There is a CRITICAL clearance that is set between the bottom of the
Stage I piston and the top of the Stage II cylinder. Over-tightening thes
e nuts will cause the top of the piston to hit the top of the Stage II cyli
nder. Too much clearance and it bottoms out on the other end.)
We received the compressor and installed new studs and steel locknuts with
Loctite. The compressor has been returned but not run, yet.
Here is what we know:
1. The FT-1 Snot valve is was flushed and functioning properly.
2. The pressure relief valve tee and checkvalves were all tested and
the system functioned normally on a bench test, with the pressure relief va
lve popping off at 750 psi.
3. A new steel line was provided to the customer, but I do not know i
f this was installed.
4. On the 4th installation of the compressor, we returned the compres
sor, shear coupling, drive pad and gear tie-wrapped as a unit for correct c
locking. We received photo verification that the compressor drive was inst
alled correctly.
5. The compressor operated normally on the last run until the steel l
ine was attached to it. Then, 1 nut backed off and the other 3 were report
ed loose. Hence, we replaced the hex nuts/lockwashers with steel locknuts
in case the lockwashers had failed and that was the only problem on the las
t run.
6. The force to shear the compressor studs is in excess of 22,000 lbs
.
7. The shear coupling appears to be a factory unit. A new one was se
nt to the customer, but returned back to me.
8. The oil return holes in the accessory case are large and not plugg
ed.
In the 20+ years that we have been overhauling air compressors, we have nev
er encountered this problem. Please use this problem as your own theoretic
al and reasoning challenge to put forth real possibilities -grasping at uni
corns, rainbows or butterflies not allowed. : )
Jill
M-14P, Inc.
Message 9
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| Subject: | Re: Air Compressor (?) Issue |
If you think about it, every time the steel line is connected the
compressor fails. That seems to say that there is a blockage between
the compressor and the pressure relief valve. Since compression is not
being built up in the aircraft the compressor output is blocked before
the pop off valve. Not much there the steel line the water catch bottle
and the line from there to the tee. One other question is the
compressor sensitive to the gasket thickness between the engine and the
compressor? Why not disconnect the compressor line and connect it to a
dive bottle and see if pressure builds up in the aircraft. Just
thinking!
Frank
----- Original Message -----
From: Jill Gernetzke
To: yak-list@matronics.com
Sent: Tuesday, October 15, 2013 2:09 PM
Subject: Yak-List: Air Compressor (?) Issue
Group,
We have met up with a head scratcher. I am throwing it out to the
group to chew on:
The Yak 52 owner purchased his aircraft on an insurance sale. The
aircraft had been totaled because of an engine fire. Attempts to talk
to the original owners and learn more about the aircraft's history have
been unsuccessful. Originally, we were contacted because the air system
was not building pressure. A photo sent by the owner, elicited a remark
by me that there seemed to be a lot of oil in the banjo/outlet valve
fitting. The compressor itself was very dirty.
The owner cleaned the outlet valve with no appreciable change in
output.
He then bought a "NOS" comp from a private party, installed it and it
failed in 2.5 hours. This compressor had actually been overhauled by us
in 2006. The nuts stripped off of the 4 studs on the bottom end of the
compressor (green case), allowing the top end off the compressor to
hammer up and down. Oil was all over the back end of the engine.
The customer then sent his original compressor for overhaul and run on
our test bench. He installed this overhauled compressor and it failed
after 40 minutes in flight. This time the 4 studs sheared off of the
bottom end of the compressor.
He sent us both failed compressors, the drive and drive gear, shear
coupling, the FT-1 "snot" valve and the pressure relief tee setup. We
built one compressor out of the two failed units. The 4 stripped studs
were replaced with new studs and installed with Loctite. The compressor
was test run and produced 925 psi. The pressure relief valve tee setup
was tested - it relieved normally - rebuilt with a new piston, new
seals in the one way checkvalves and the pressure set to 50 atm. (The
pressure relief valve had a Teflon seal which was in very poor
condition.) The snot valve was tested, flushed and retested. The
compressor, gaskets and drive unit were secured to one another in the
proper alignment for the reinstall.
The air compressor was returned to the customer and it was reinstalled
without attaching the steel air line. Everything was normal for about
1.5 hours of ground runs.
A flight was completed with the steel coiled air line still not
attached. The flight was normal.
The steel line was reattached and 90 minutes of ground run time. He
noticed that pressure was not building as it should and opened the
cowling to find one of the 4 hold-down nuts backing off. He also
reported that the other 3 nuts were not tight. The owner drilled and
safety wired the nuts.
(Note: There is a CRITICAL clearance that is set between the bottom
of the Stage I piston and the top of the Stage II cylinder.
Over-tightening these nuts will cause the top of the piston to hit the
top of the Stage II cylinder. Too much clearance and it bottoms out on
the other end.)
We received the compressor and installed new studs and steel locknuts
with Loctite. The compressor has been returned but not run, yet.
Here is what we know:
1. The FT-1 Snot valve is was flushed and functioning properly.
2. The pressure relief valve tee and checkvalves were all tested
and the system functioned normally on a bench test, with the pressure
relief valve popping off at 750 psi.
3. A new steel line was provided to the customer, but I do not
know if this was installed.
4. On the 4th installation of the compressor, we returned the
compressor, shear coupling, drive pad and gear tie-wrapped as a unit for
correct clocking. We received photo verification that the compressor
drive was installed correctly.
5. The compressor operated normally on the last run until the
steel line was attached to it. Then, 1 nut backed off and the other 3
were reported loose. Hence, we replaced the hex nuts/lockwashers with
steel locknuts in case the lockwashers had failed and that was the only
problem on the last run.
6. The force to shear the compressor studs is in excess of
22,000 lbs.
7. The shear coupling appears to be a factory unit. A new one
was sent to the customer, but returned back to me.
8. The oil return holes in the accessory case are large and not
plugged.
In the 20+ years that we have been overhauling air compressors, we
have never encountered this problem. Please use this problem as your
own theoretical and reasoning challenge to put forth real possibilities
-grasping at unicorns, rainbows or butterflies not allowed. : )
Jill
M-14P, Inc.
Message 10
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| Subject: | Re: Air Compressor (?) Issue |
One thought, since there was a fire that involved the firewall were the chec
k valves at the pop off valve rebuilt or replaced. Is it possible that the l
ower check valve between the snot bottle and the pop off valve and the filte
r are reversed. Instead of the one way valve arrow on the check valve pointi
ng to the filter and theophylline off valve could it be pointing at the snot
bottle. Did y'all re-assemble the H or was it done in the field? Is the fil
ter patent or is it clogged up from carbon deposited?
I saw your #2 in the summary list that referred to testing the H setup. Was i
t disassemble after ya'll shipped it. As you know the check valve direction w
ill have a big impact on air flow.
Just a though.
Doc
Sent from my iPad
On Oct 15, 2013, at 4:09 PM, "Jill Gernetzke" <jill@m-14p.com> wrote:
> Group,
>
> We have met up with a head scratcher. I am throwing it out to the group t
o chew on:
>
> The Yak 52 owner purchased his aircraft on an insurance sale. The aircraf
t had been totaled because of an engine fire. Attempts to talk to the origi
nal owners and learn more about the aircraft=99s history have been uns
uccessful. Originally, we were contacted because the air system was not bui
lding pressure. A photo sent by the owner, elicited a remark by me that the
re seemed to be a lot of oil in the banjo/outlet valve fitting. The compres
sor itself was very dirty.
> The owner cleaned the outlet valve with no appreciable change in output.
> He then bought a "NOS" comp from a private party, installed it and it fai
led in 2.5 hours. This compressor had actually been overhauled by us in 200
6. The nuts stripped off of the 4 studs on the bottom end of the compressor
(green case), allowing the top end off the compressor to hammer up and down
. Oil was all over the back end of the engine.
>
> The customer then sent his original compressor for overhaul and run on our
test bench. He installed this overhauled compressor and it failed after 40
minutes in flight. This time the 4 studs sheared off of the bottom end of t
he compressor.
>
> He sent us both failed compressors, the drive and drive gear, shear coupli
ng, the FT-1 =9Csnot=9D valve and the pressure relief tee setup
. We built one compressor out of the two failed units. The 4 stripped stud
s were replaced with new studs and installed with Loctite. The compressor w
as test run and produced 925 psi. The pressure relief valve tee setup was t
ested =93 it relieved normally - rebuilt with a new piston, new seals
in the one way checkvalves and the pressure set to 50 atm. (The pressure re
lief valve had a Teflon seal which was in very poor condition.) The snot val
ve was tested, flushed and retested. The compressor, gaskets and drive unit
were secured to one another in the proper alignment for the reinstall.
>
> The air compressor was returned to the customer and it was reinstalled wit
hout attaching the steel air line. Everything was normal for about 1.5 hours
of ground runs.
>
> A flight was completed with the steel coiled air line still not attached.
The flight was normal.
>
> The steel line was reattached and 90 minutes of ground run time. He notic
ed that pressure was not building as it should and opened the cowling to fi
nd one of the 4 hold-down nuts backing off. He also reported that the other 3
nuts were not tight. The owner drilled and safety wired the nuts.
>
> (Note: There is a CRITICAL clearance that is set between the bottom of th
e Stage I piston and the top of the Stage II cylinder. Over-tightening thes
e nuts will cause the top of the piston to hit the top of the Stage II cylin
der. Too much clearance and it bottoms out on the other end.)
>
> We received the compressor and installed new studs and steel locknuts with
Loctite. The compressor has been returned but not run, yet.
>
> Here is what we know:
> 1. The FT-1 Snot valve is was flushed and functioning properly.
> 2. The pressure relief valve tee and checkvalves were all tested and
the system functioned normally on a bench test, with the pressure relief va
lve popping off at 750 psi.
> 3. A new steel line was provided to the customer, but I do not know i
f this was installed.
> 4. On the 4th installation of the compressor, we returned the compre
ssor, shear coupling, drive pad and gear tie-wrapped as a unit for correct c
locking. We received photo verification that the compressor drive was insta
lled correctly.
> 5. The compressor operated normally on the last run until the steel l
ine was attached to it. Then, 1 nut backed off and the other 3 were reporte
d loose. Hence, we replaced the hex nuts/lockwashers with steel locknuts in
case the lockwashers had failed and that was the only problem on the last r
un.
> 6. The force to shear the compressor studs is in excess of 22,000 lb
s.
> 7. The shear coupling appears to be a factory unit. A new one was s
ent to the customer, but returned back to me.
> 8. The oil return holes in the accessory case are large and not plug
ged.
>
> In the 20+ years that we have been overhauling air compressors, we have ne
ver encountered this problem. Please use this problem as your own theoretic
al and reasoning challenge to put forth real possibilities =93grasping
at unicorns, rainbows or butterflies not allowed. : )
>
> Jill
> M-14P, Inc.
>
>
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
Message 11
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| Subject: | Re: Air Compressor (?) Issue |
If this plane came from the east coast I know it well. I flew A LOT with the owner
who had before the ins company sold it and don't ever remember hearing about
a compressor issue. ever. I would guess there are some big time metallurgy
issues after watching it burn.
--------
Keith McKinley
700HS
X26 Sebastian, FL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=410668#410668
Message 12
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| Subject: | Re: Staking a Housai exhaust valve (or M-14) |
I know just about everyone on this list is saying "for the love of GOD not again"
so I'll stop it right here and get back to the staking question at the heart
of this post and not MMO.....
....but thanks!
[Wink]
--------
Keith McKinley
700HS
X26 Sebastian, FL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=410670#410670
Message 13
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| Subject: | Re: Staking a Housai exhaust valve (or M-14) |
But the real question we want to know
Was it the lack of MMO
That precipitated your situation
Doc
Sent from my iPad
On Oct 15, 2013, at 9:42 PM, "keithmckinley" <cetopfed@gmail.com> wrote:
>
> I know just about everyone on this list is saying "for the love of GOD not again"
so I'll stop it right here and get back to the staking question at the heart
of this post and not MMO.....
>
>
> ....but thanks!
>
>
> [Wink]
>
> --------
> Keith McKinley
> 700HS
> X26 Sebastian, FL
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=410670#410670
>
>
>
>
>
>
>
>
>
>
Message 14
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| Subject: | Re: Air Compressor (?) Issue |
Hello Jill,
I wonder why the shear pins did not snap before the studs let go - unless you did
not really check this ? I suspect an insufficient oil supply to the compressor
and seized pistons. After the pins snapped the whole shear coupling may have
seized again and consequently leading to breaking the studs. Did you look
inside the compressor cylinders to check them for seizure ? With poor oil supply
to the compressor drive I can imagine a snapped shear coupling will seize again
in little time causing more damage. Please keep us posted with your findings.
Cheers
Vic
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=410678#410678
Message 15
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| Subject: | Re: Air Compressor (?) Issue |
Probably a stupid remark, but are you sure that the shear coupling was OK?
I've seen shear couplings that were repaired with STEEL from nails.
Jan
From: "jill@m-14p.com" <jill@m-14p.com>
Subject: Yak-List: Air Compressor (?) Issue
Group,
We have met up with a head scratcher. I am throwing it out to the group to
chew on:
The Yak 52 owner purchased his aircraft on an insurance sale. The aircraft
had been totaled because of an engine fire. Attempts to talk to the
original owners and learn more about the aircraft=B9s history have been
unsuccessful. Originally, we were contacted because the air system was not
building pressure. A photo sent by the owner, elicited a remark by me that
there seemed to be a lot of oil in the banjo/outlet valve fitting. The
compressor itself was very dirty.
The owner cleaned the outlet valve with no appreciable change in output.
He then bought a "NOS" comp from a private party, installed it and it
failed in 2.5 hours. This compressor had actually been overhauled by us in
2006. The nuts stripped off of the 4 studs on the bottom end of the
compressor (green case), allowing the top end off the compressor to hammer
up and down. Oil was all over the back end of the engine.
The customer then sent his original compressor for overhaul and run on our
test bench. He installed this overhauled compressor and it failed after 40
minutes in flight. This time the 4 studs sheared off of the bottom end of
the compressor.
He sent us both failed compressors, the drive and drive gear, shear
coupling, the FT-1 =B3snot=B2 valve and the pressure relief tee setup. We
built one compressor out of the two failed units. The 4 stripped studs wer
e
replaced with new studs and installed with Loctite. The compressor was tes
t
run and produced 925 psi. The pressure relief valve tee setup was tested =AD
it relieved normally - rebuilt with a new piston, new seals in the one way
checkvalves and the pressure set to 50 atm. (The pressure relief valve had
a
Teflon seal which was in very poor condition.) The snot valve was tested,
flushed and retested. The compressor, gaskets and drive unit were secured
to one another in the proper alignment for the reinstall.
The air compressor was returned to the customer and it was reinstalled
without attaching the steel air line. Everything was normal for about 1.5
hours of ground runs.
A flight was completed with the steel coiled air line still not attached.
The flight was normal.
The steel line was reattached and 90 minutes of ground run time. He notice
d
that pressure was not building as it should and opened the cowling to find
one of the 4 hold-down nuts backing off. He also reported that the other 3
nuts were not tight. The owner drilled and safety wired the nuts.
(Note: There is a CRITICAL clearance that is set between the bottom of the
Stage I piston and the top of the Stage II cylinder. Over-tightening these
nuts will cause the top of the piston to hit the top of the Stage II
cylinder. Too much clearance and it bottoms out on the other end.)
We received the compressor and installed new studs and steel locknuts with
Loctite. The compressor has been returned but not run, yet.
Here is what we know:
1. The FT-1 Snot valve is was flushed and functioning properly.
2. The pressure relief valve tee and checkvalves were all tested and
the system functioned normally on a bench test, with the pressure relief
valve popping off at 750 psi.
3. A new steel line was provided to the customer, but I do not know i
f
this was installed.
4. On the 4th installation of the compressor, we returned the
compressor, shear coupling, drive pad and gear tie-wrapped as a unit for
correct clocking. We received photo verification that the compressor drive
was installed correctly.
5. The compressor operated normally on the last run until the steel
line was attached to it. Then, 1 nut backed off and the other 3 were
reported loose. Hence, we replaced the hex nuts/lockwashers with steel
locknuts in case the lockwashers had failed and that was the only problem o
n
the last run.
6. The force to shear the compressor studs is in excess of 22,000 lbs
.
7. The shear coupling appears to be a factory unit. A new one was
sent to the customer, but returned back to me.
8. The oil return holes in the accessory case are large and not
plugged.
In the 20+ years that we have been overhauling air compressors, we have
never encountered this problem. Please use this problem as your own
theoretical and reasoning challenge to put forth real possibilities
=ADgrasping at unicorns, rainbows or butterflies not allowed. : )
Jill
M-14P, Inc.
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