Can I use a yellow tagged camshaft in my Wittman Tailwind?

I have a Lycoming O-320-D2A that will be going into a Wittman Tailwind. The crankcase and crankshaft are yellow tagged. The camshaft is really pitted and will need to be replaced. I imagine the followers will need replacing also unless refurbishing them isn’t a big deal.

My question is this: There’s a possibility that I can get a yellow tagged P/N 76097 camshaft (that the seller claims can be used for 320 and 360 series engines). Will this fit?

DAVID LAMPHERE

via email

All of the information I can find indicates the only camshaft currently used in this specific engine is Lycoming part number LW18837. The yellow tagged camshaft part number 76097 that the seller claims may be used in your engine is not approved for use in the O-320-D2A. It is, however, used in several models of the Lycoming O-360 series engines.

If you follow the Lycoming recommendation, you should always replace the cam followers (tappet bodies) when installing a new camshaft. From my personal experience, refurbishing cam followers has not been tremendously successful and my suggestion would be to install new followers.

Good luck with your Wittman Tailwind. If you have as much fun building and flying it as Steve Wittman did designing, building, and flying his, you will have reached the ultimate goal of those of us who enjoy general aviation.

I understand that you are the man with the answers to Lycoming questions. I am trying to understand sump and carburetor combinations for the O-320. I believe in about 1959 Lycoming made some changes in the sump and carburetors. Prior to the change it seems that the combination was Marvel-Schebler Model MA-4SPA part number 10-3678-12 carburetor and part number 69370 sump assembly (along with other part numbers). In 1959, or thereabout, Lycoming recommended going to the 10-3678-32 carburetor and a different sump, with a vertical riser. Apparently the carburetor/intake hole size changed from about 2.4 inches to 1.9 inches.

My questions are: What is the part number of the correct sump that is to be used with the -32 carburetor? Can a -32 carburetor be used on a sump with a 2.4 hole size?

I appreciate any assistance you can give me with these questions.

CHARLES WINDHAM

via email

Your question takes me back in time a bit and I really had to do some research on this one. I recall this was still a much discussed subject when I began as a Lycoming service rep, so I guess it should come as no surprise that there still may be an odd question. This subject was covered in Lycoming Service Bulletin SB258 dated May 29, 1959, which stated all engines shipped to Piper after Feb. 20, 1959, incorporated the sump riser sleeve and the -32 carburetor. This is still an active Service Bulletin should you desire to check it out for yourself.

The correct oil sump part number to be used with the 10-3678-32 carburetor is Lycoming part number 72362. To my knowledge you may not use the -32 carburetor with the Lycoming oil sump part number 69370. In doing my research, I could find neither application nor traceability for this latter combination.

Remember, this change was a cure for a “”rough engine”” operation from an excessively rich mixture condition so we wouldn’t want to have any combination that may cause the engine to exhibit a similar condition. Let’s stick with the combination that has proven its worth over the years.

Can I put an O-320-E2D in my PA-16 Clipper without a million mods?

BETHANN SCHNEIDER

via email

I’m sorry to report that I was unable to locate any FAA STC approvals for installing a Lycoming O-320-E2D in your Piper PA-16. As a matter of fact, I found no STCs for any engine other than the original Lycoming model O-235-C1.

I have one suggestion that may be of some help and that would be to contact the Short Wing Piper Club to see if it is aware of any engine STCs for your aircraft.

I’m sorry I couldn’t be of more help, but hopefully someone will read this and contact you with information that will answer your question.

Paul McBride, recognized worldwide as an expert on engines, retired after almost 40 years with Lycoming. Send your questions to: AskPaul@GeneralAviationNews.com.

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