Today's Message Index:
----------------------
1. 12:56 AM - Rotax 912S Hard Starting (Phil & Michele Miller)
2. 08:09 AM - Re: Rotax 912S Hard Starting (flyseaplane)
3. 09:10 AM - Re: Rotax 912S Hard Starting (Justin)
4. 09:29 AM - Re: roller rocker arms,Lycoming (David L Ahrens)
5. 09:58 AM - Re: Pressure Sensors (Roberto Giusti)
6. 10:07 AM - Re: Mazda rotary (Nielsenbe@aol.com)
7. 01:32 PM - Re: Re: roller rocker arms,Lycoming (Archie)
8. 03:01 PM - Re: Re: roller rocker arms,Lycoming (Jim & Jeanette Oberst)
9. 04:08 PM - Re: Rotax 912S Hard Starting (Dave Austin)
10. 07:36 PM - Re: Front seal leaking. WHY? (Mcculleyja@aol.com)
11. 10:20 PM - Re: Re: roller rocker arms,Lycoming (Aucountry@aol.com)
12. 10:20 PM - Re: Re: roller rocker arms,Lycoming (Aucountry@aol.com)
Message 1
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| Subject: | Rotax 912S Hard Starting |
--> Engines-List message posted by: "Phil & Michele Miller" <millerpg@ps.gen.nz>
Hi, Listers,
I've been lurking around this list for a while and wonder if anyone can
help me.
I have a Rotax 912ULS which is always extremely difficult to start but
only on the first start of the day. When it is warm it always starts
relatively easily if a little harshly. It has been this way since new
and now has 72 hours total time. We have done everything by the book and
have checked and re-checked everything. The symptoms are exactly what
you would expect if the ignition timing was way too far advanced.
It has a 32 amp/hour battery and the leads are sized correctly for the
current draw and run length. It is fitted with the gearbox slipper cluch
as recommended by Rotax.
Ambient temperature here is not cold as it rarely goes below 50 degrees
fahrenheit.
Any help will be appreciated as this problem has been going on for far
too long and is driving me nuts. There is no local Rotax service agent.
I don't know where else to turn for help
Thanks in advance,
Phil Miller
New Zealand
912ULS in a Zenair CH701
Message 2
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| Subject: | Re: Rotax 912S Hard Starting |
--> Engines-List message posted by: "flyseaplane" <flyseaplane@netzero.net>
"Phil & Michele Miller"
"I have a Rotax 912ULS which is always extremely difficult to start ......It
is fitted with the gearbox slipper cluch as recommended by Rotax."
I have a friend who installed a Rotax 912S 100HP which had a hard time
starting cold. It turned out to be his Propeller. Rotax specifies that the
weight of the propeller tips has a profound effect on the ability to start
this engine. During cranking, the prop speeds up and slows down slightly
during each compression stroke. The harmonics of the amount of effort needed
to raise the piston on the compression stroke and the inertia of the prop
speeding up and slowing down slightly tend to compound each other. Rotax
does specify that the propeller must not weigh more than a specified amount
of mass from a specified distance from the hub centre. See if you can try a
prop with lighter tips and the problem should go away.
Good Luck,
Linc
Message 3
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| Subject: | Re: Rotax 912S Hard Starting |
--> Engines-List message posted by: "Justin" <jmw116@socal.rr.com>
What is your checklist to start it? You are eithernot getting enough fuel or
you are flooding it and not knowing it.
Justin, KR2S
http://n116jw.topcities.com/
----- Original Message -----
From: "Phil & Michele Miller" <millerpg@ps.gen.nz>
Subject: Engines-List: Rotax 912S Hard Starting
> --> Engines-List message posted by: "Phil & Michele Miller"
<millerpg@ps.gen.nz>
>
> Hi, Listers,
>
> I've been lurking around this list for a while and wonder if anyone can
> help me.
>
> I have a Rotax 912ULS which is always extremely difficult to start but
> only on the first start of the day. When it is warm it always starts
> relatively easily if a little harshly. It has been this way since new
> and now has 72 hours total time. We have done everything by the book and
> have checked and re-checked everything. The symptoms are exactly what
> you would expect if the ignition timing was way too far advanced.
>
> It has a 32 amp/hour battery and the leads are sized correctly for the
> current draw and run length. It is fitted with the gearbox slipper cluch
> as recommended by Rotax.
>
> Ambient temperature here is not cold as it rarely goes below 50 degrees
> fahrenheit.
>
> Any help will be appreciated as this problem has been going on for far
> too long and is driving me nuts. There is no local Rotax service agent.
> I don't know where else to turn for help
>
> Thanks in advance,
> Phil Miller
> New Zealand
> 912ULS in a Zenair CH701
>
>
Message 4
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| Subject: | re: roller rocker arms,Lycoming |
--> Engines-List message posted by: David L Ahrens <daviddla@juno.com>
Does anyone have information regarding roller rocker arms as sold and
used on Lycoming engines?
I have been curious about the use of the roller arms ever since I have
seen the excessive wear the Lycoming valve guides seem to suffer from. I
do not know if roller rockers would help reduce the valve guide wear or
if the wear is caused by other factors such as low oil flow to this area.
Dave Ahrens
Message 5
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| Subject: | Pressure Sensors |
--> Engines-List message posted by: "Roberto Giusti" <roby@mail.com>
I recently sent an email to Westach regarding their senders:
Here is the email and their reply:
Can your solid state transducers (Kavilco) be
mounted directly on a Lycoming engine or must they be remote mounted
like the standard sensors due to vibration problems (risk of
separation and loss of oil/fuel pressure)?
Reply:
The Kavlico senders can be mounted directly to the engine. But if heat
is an issue ( over 250 deg like froman exhaust manifold ) then remote
mounting is recommended.
THANK YOU PETE CORNELIUS TECH SUPPORT
WESTBERG MFG. WESTACH
All the a/c mechanics that I talked to told me to mount the senders
remotely, but they had never seen a solid state sender.
I am not at all an expert, but IF these senders are designed to
be mounted directly on our engines and they are guarantied not to snap
off,
I would think that this would simplify the installation, bring the
weight and parts count down and improve safety!
The specs for Kavlico's P165 Pressure Transducer (from their web site)
state:
Vibration: 10G's peak to peak sinusoidal.
Shock: 75G's 1/2 sine wave.
I won't even pretend to understand what this means, but maybe someone
can.
Gary, do you have any data you can share with us?
Roberto Giusti
RV8 (wings)
Parma Italy
>...As
> for PRESSURE sensors, we (Kavlico) build pressure sensors for
> aircraft engine applications, some of which are
> direct-mounted to the engine. These are for both oil and
> fuel pressure. It depends on the ruggedness of the sensor
> and the vibration level of the environment as to whether they
> can be direct-mounted. To say that the vibration will
> destroy any sensor is an oversimplification. Incidentally,
> some of our sensors are remote-plumbed from the source, but
> then hard-mounted to the cooling shroud. Go figure. The
> cooling shroud could easily amplify the engine vibration,
> making it worse than a direct-mount.
>
> Gary Casey
Message 6
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| Subject: | Re: Mazda rotary |
--> Engines-List message posted by: Nielsenbe@aol.com
Do you think that HP rating could go over 300 safely with a super charger? I
am really looking for a 350-400HP motor. Thanks, Brad
Message 7
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| Subject: | Re: re: roller rocker arms,Lycoming |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
> Does anyone have information regarding roller rocker arms as sold and
> used on Lycoming engines?
> I have been curious about the use of the roller arms ever since I have
> seen the excessive wear the Lycoming valve guides seem to suffer from. I
> do not know if roller rockers would help reduce the valve guide wear or
> if the wear is caused by other factors such as low oil flow to this area.
> Dave Ahrens
Dave, I have been building racing engines for years, and roller rockers
are used exclusively on pushrod engines for racing. (these are NOT the
street-type normally found in speed shops).
I have seen two people fail at producing them for aircraft, and have no
knowledge as to why. The very best professional rockers cost around
$25. ea. and will withstand lifts of ,90 and spring pressures of close to
1000 lbs. so I have no idea what the problem is there.
Another problem I have found from aviation cylinder work is that most
of the equipment is not very accurate by racing standards. (that is why
most aviation shops must lap valves).
I have found cases where the valve guides were not accurately bored,
and caused side loading on the valve which resulted in premature guide
wear. I have also found rockers that had inaccurate ratios, and were
improperly ground, causing the same results. (more in Cont. than Lyc.)
I do not know of anyone currently STC'ng them for aircraft.
Archie
Message 8
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| Subject: | Re: re: roller rocker arms,Lycoming |
--> Engines-List message posted by: "Jim & Jeanette Oberst" <joberst@cox-internet.com>
I believe the wear is caused by Lycoming's design of using the valve stems
and guides to remove the heat that the valves collect during ignition.
Roller rockers may not help.
Jim Oberst
----- Original Message -----
From: "David L Ahrens" <daviddla@juno.com>
Subject: Engines-List: re: roller rocker arms,Lycoming
> --> Engines-List message posted by: David L Ahrens <daviddla@juno.com>
>
> Does anyone have information regarding roller rocker arms as sold and
> used on Lycoming engines?
> I have been curious about the use of the roller arms ever since I have
> seen the excessive wear the Lycoming valve guides seem to suffer from. I
> do not know if roller rockers would help reduce the valve guide wear or
> if the wear is caused by other factors such as low oil flow to this area.
> Dave Ahrens
>
>
Message 9
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| Subject: | Re: Rotax 912S Hard Starting |
--> Engines-List message posted by: "Dave Austin" <daveaustin2@sprint.ca>
Phil,
I had a similar starting problem with my 912UL which was finally resolved by
setting the plug gaps to no more than 20 thou. Never a problem since.
Also, make sure the throttles are fully closed on the cold startup.
Dave Austin 601HDS - 912 530 hrs
Message 10
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| Subject: | Re: Front seal leaking. WHY? |
--> Engines-List message posted by: Mcculleyja@aol.com
There is an old Lycoming Service Bulletin #204 that calls attention to the
fact that if the tachometer shaft centering spacer is inadvertently installed
on the breather outlet tube side of the breather slinger, instead of the
camshaft gear side of the slinger, the spacer can block the breather outlet
and cause a high pressure buildup in the crankcase, resulting in blowing out
the nose seal.
They found the cause of the blowout to be elusive to trouble shoot because it
only became a problem when full power was applied, causing the increased flow
from the crankcase to move the spacer to a position blocking the outlet.
If you haven't instrumented to read the crankcase pressure before and during
the high power operation, you may want to consider doing this. A simple way
is to use an old unserviceable airspeed indicator plumbed temporarily into
the crankcase via the oil dipstick tube for example. The maximum reading is
specified by some Lycoming document that I can't find at the moment, but
someone else on the list may remember or a call to the factory technical
assistance number can probably get it.
Jim McCulley
----- Original Message -----
From: "flyseaplane" <flyseaplane@netzero.net>
Subject: Engines-List: Front seal leaking. WHY?
> --> Engines-List message posted by: "flyseaplane"
<flyseaplane@netzero.net>
>
> "Another possibility to consider is wear of the cam....."
>
> Ummmm.......shouldn't be. It's all new stuff (well, yellow tagged
re-manned,
> or whatever) and the engine was pickled properly after assembly and before
> storage three years ago.
> It has GOBS of power. Warp Drive said to set the prop at 10 degrees of
> pitch, I decided to go with 13 degrees to load the engine up harder to get
> the rings to seat in. It almost hit redline. I didn't have a spring scale
> tied on the tailwheel, but the amount of thrust produced during the test
run
> was unbelievable. I'm really curious to see how she flies.
> I really don't think it is the cam - the rings may not be seated yet, but
I
> still don't think that would cause the oil to seep out. I'll have some
time
> off tomorrow and I'll look everything over. Maybe pull the seal and have
> look at it.
>
> Thanks guys,
> Linc
>
Message 11
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| Subject: | Re: re: roller rocker arms,Lycoming |
--> Engines-List message posted by: Aucountry@aol.com
In a message dated 01/25/03 01:33:47 PM, archie97@earthlink.net writes:
> I have found cases where the valve guides were not accurately bored,
> and caused side loading on the valve which resulted in premature guide
> wear.=A0 I have also found rockers that had inaccurate ratios, and were
> improperly ground, causing the same results. (more in Cont. than Lyc.)
> I do not know of anyone currently STC'ng them for aircraft.
> Archie
>
OH, and where are you located?
Message 12
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| Subject: | Re: re: roller rocker arms,Lycoming |
--> Engines-List message posted by: Aucountry@aol.com
In a message dated 01/25/03 01:33:47 PM, archie97@earthlink.net writes:
> I have found cases where the valve guides were not accurately bored,
> and caused side loading on the valve which resulted in premature guide
> wear.=A0 I have also found rockers that had inaccurate ratios, and were
> improperly ground, causing the same results. (more in Cont. than Lyc.)
> I do not know of anyone currently STC'ng them for aircraft.
> Archie
>
Do you have your own shop? Do you do cars or planes or both?
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