Cylinder Kits: what's the thought??

[joea]

Joey,

Have you tried using MMO or mogas in the plane?

Joe A

[MikeB]

Agree with Joe. I'd try some Marvel Mystery Oil and see if that helps. I suspect that if you're using 100LL on a regular basis it's probably loading or reducing the clearance between the valves and the guides. On the other hand it might be necessary to clean the stems and ream the guides. It's a little 'touchy' but it can be done by an experienced mechanic by dropping the valve into the cylinder and working through the spark plug hole.

MikeB

[Captgrumps]

My gas supplier just made ethonol free gas available. Their is a Sanata Claus.

[joea]

Doug,

Great to hear it.

When I get time over here will start looking around to see if its happening in my neck of the woods.

Joe A

[Sgt. NCSHP]

I have been running 50% nonethanol mogas and 50% avgas with 4oz of MMO per 10 gallons. I talked with Jeff Sword (Don's Dream Machines)and his take is that the MMO could very well be causing the problem. His method to prove point was to pour some MMO in a can and heat with torch to about 1200 dgrees. He said all you will have left is carbon. Last year I tried increasing the mogas ans still had stuck valves. Each time my mechanic comes down and does the rope trick and uses some 1200 sandpaper on the stem and a .437 reamer in the guide. All I have seen on the reamer is carbon and no metal flakes when he does it. I'm just gettin concerned about a valve gettin a hot spot from not sealing and failing while flying. Is this something of concern or am I just being to anal?

[Roger Anderson]

Wow...seems like you've covered all the bases. I have heard that an excessive amount (if a little bit is good, then a whole lot is better) of MMO can cook itself. C85s, especially with chrome cylinders can run hot, much hotter than A65s. Do you have a cylinder head temp gage? Could your baffling not be giving good air flow causing high temps? My chrome C85 in my Ercoupe ran hotter than hell.....figuratively speaking. Just wild thoughts.

[Sgt. NCSHP]

The baffling is up tight and I checked the inner baffling Saturday and it looked good. I don't have CHT. Its non electric 7DC..would be nice to know what they are running but then I don't know what I could do about it. The firewall mod has been done and the lower cowl mod..in the winter I seldom see oil temps over 140

[Captgrumps]

How many hours on the engine, who did the overhaul--was it to new tolerances or just afield overhaul--do you have the documentation? There are too many variables--little Continental engines need to be run--and I mean run--I know the FAA has max rpm's in the specs but the the engines are used for other things and run wide open..Sometimes I think the rpm limitation is on the prop, not the engine. Our problem with our little airplanes is babying the engines since the are so precious to us and especially our wife/girl friend/alimony recipent who sometimes think she would rather have a new car. In my 60 so years I have only had one stuck valve in a 65 Continental--that was when we went to 100 Octane and I used the leather hammer and Sears portable drill trick. But then last night I stayed at the Holiday Inn Express had three cases of Heinkens I was talking to Blakesburg when the weather turned sour on my driving permit.

Doug

PS--You must remember that all the Continenal/FAA specs on these old engine were developed on less than 80 octane gas, not 100 octane, not ethonol car gas, not non-ethonol gas or Marvel Mystery oil. So just like the race care guys do, to join the 21st century and you adapt. After an engine is new the internal specs vary widely just like STC's and field approvals..Ever read the statement on the top of the back side of the current FAA Form 337? Let common sense prevail.