Intake valves and 100LL (A-65)

[PhilP]

First question: Is there ANYONE here who knows where you can get (4) 100 octane intake valves for an A-65?? I've tried everywhere from coast to coast, (Fresno etc...) including talking with the folks over at Continental...(no dice)

I'm guessing no

So next question: Does anyone here run 100LL in their A-65 almost exclusively with 80 octane Intake valves?? I know the intake v's are cooled and less suseptible to wear than the exhaust valves are, but I'm looking for some input or experience from A-65 flyers out there because that's what I'm going to have to go with. The 100 oct exhaust valves we're not a problem to find...

I'd be happy to run Mogas in it when home, but when going on trips, you just don't have a choice and I'd rather have 100LL sitting in it while I'm gone. Anyone have any problems, excessive wear when using the 80 intake valves??

Thoughts??

Thanks guys!

Phil

[Guest]

Re: Intake valves and 100LL (A-65)

I forgot what intake valves I have, but my MOGAS stc requires running leaded avgas every fifty hours.

I am wondering if yours does too and this problem you are running into can be turnded into a way to comply with that.

I have no valve problems.

Dave.

[d.grimm]

Re: Intake valves and 100LL (A-65)

I use TCP gasoline additive and for the last year has solved my 100 oct. and lead problems. Never had problems with autogas. Stopped using it when they put ethanol in.(per STC) Had to pull 3 cylinders in two years for lead problems prior to TCP.

[Guest]

Re: Intake valves and 100LL (A-65)

just checked I have 100 octane exhaust (21479) and 80 octane intake (21359).

Fresno's add in trade-a-plane shows the 100 octane intakes, for what that's worth

[Guest]

Re: Intake valves and 100LL (A-65)

I would also check in trade-a-plane for a seller named Robert Webber and ask him.

[PhilP]

Re: Intake valves and 100LL (A-65)

Thanks for the feedback so far guys... Yea, Fresno has been waiting since May of '07 for these valves. They have called everywhere trying to find them, and can't.

So thus far the consensus is 100LL isn't burning up anyone's 80 octane Intake valves??

-Phil

[Guest]

Re: Intake valves and 100LL (A-65)

I think you are correct, best way to describe my use is that I use mogas for 4 tanks and the 5th is 100ll.

If you really want the valves check out Robert Webber. He may surprise you.

Dave

[flyguy]

Re: Intake valves and 100LL (A-65)

Why would extra lead "burn up" valves?????? Ever check valves on an engine. Intakes get carboned up, and exhausts get cremated, but not from lead. Problems with auto engines was old type valve seats would burn with switch to unleaded because they needed a coating of lead to lubricate and protect them. What IS the difference between 80 and 100 octane valves and the purpose for the difference? Anyone here know?
Thanks for the tip on the TCP.
DC

[Guest]

Re: Intake valves and 100LL (A-65)

Darryl,

Here is what I found so far;

Continental SB M77-3 that mentions the 100LL intake part # for the a-65 but offers no explanation why. also it refers to M76-8

Continental SB M76-8 that offers and explanation why but does not mention an a-65

Dave

[taylorcraftbc65]

Re: Intake valves and 100LL (A-65)

I'm a LOT more afraid of the ethenol in autogas than the lead in 100LL. I also run TCP in the gas, and while I have not had the engine apart, there are NO lead deposits on my plugs. Brie

[flyguy]

Re: Intake valves and 100LL (A-65)

Interesting reading Dave, thanks.

Guess the automotive engine concept of older valve seats needing leaded gas doesn't hold up with low compression TCM engines.

I hadn't though about it much, but the lead (oxide?) whatever, that one cleans out of spark plugs does seem abrasive (to more than our temperament ), so if it gets between the valve and the seat (likely), I could see it chewing things up a bit.
Strange? that it doesn't seem to affect the higher compression engines per their failure data. Wonder what that is all about. Lots of weird stuff goes on inside internal combustion engines.
Darryl

[Guest]

Re: Intake valves and 100LL (A-65)

I'm a LOT more afraid of the ethenol in autogas than the lead in 100LL. I also run TCP in the gas, and while I have not had the engine apart, there are NO lead deposits on my plugs. Brie

My mogas STC forbids the use of fuel that contains ethanol