There are no stupid questions… Just unusual ones that, unfortunately, don’t have the desired answer

This seems like a stupid question but I’m going to ask anyway. Did Lycoming ever have a service kit to put hydraulic lifters into the O-235?

I’ve got a group of owners in a 152 Cessna who seem likely to trade back and forth on the oil changes and forget the valve lash check. They’re coming up on TBO and I think I’d be doing them a favor if I could talk them into a conversion to hydraulics if Lycoming had such a kit.

Thanks for your help.


Quest Aviation

Tea, S.D.

This is a question that I don’t think I’ve ever heard before, and that includes all those odd, strange and curious questions one expects to hear at Oshkosh or Sun ‘n Fun.

I understand your concern that, even though the current owners of a Cessna 152 with the Lycoming O-235 series engine appear to provide routine maintenance, they may overlook the importance of following the manufacturer’s recommendation calling for checking the valve clearance during the 100-hour inspection. To alleviate this situation you wonder if Lycoming has ever had a conversion kit to install hydraulic lifters, as used in almost all other Lycoming engine models.

I’m sorry to say there is nothing available, so it looks like your challenge is to better educate the owners as to the importance of following the manufacturer’s publications. Following the recommendations should assure them of maintaining the engine’s health and getting good service life from it.

Sorry I couldn’t help you with this one, Dan, and I hope you can work with the owners to change their thinking about this valve adjusting thing, when they get their engine overhauled and are back in the air.

I have a VO-360-A1B that has been converted to an O-360 series for experimental aircraft use. A question has been posed: Would there be a thrust situation at the crank-to-case interface?


via email

While you didn’t send all the facts, I suspect this engine will be installed in an experimental, fixed-wing aircraft. I also suspect this engine was mounted in what most folks would consider a “”pusher type”” installation when used as a VO-360 in a helicopter application. If it is now to be used in a fixed-wing experimental aircraft as an ordinary “”tractor”” application, you will have no issues regarding crankshaft thrust.

Generally speaking, Lycoming engines can be — and are — installed in both configurations with no restrictions that I am aware of. If you think about it, there have been several different Lycoming engine models installed in the VariEze, Long-EZ, Cozy and Velocity, to name a few, as well as the Rutan Defiant, which used two Lycoming engines in a push/pull configuration.

George, I’d say if you haven’t already begun your project, get going right now and put any concerns regarding crankshaft thrust behind you.

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

Leave a Reply

Your email address will not be published. Required fields are marked *