RE: Interference Engines
Em - Jolly - not chastised - only a friendly harassment (the wink-wink nudge-nudge smiley face).
I'm familiar with OHC auto engines that are classified as interference/non-interference. Warning to be very aware of the timing belt replacement interval. But our 4 stroke RC engines have OHV with pushrods. I don't recall hearing any "cautionary" heads up on OHV auto engines in my short 60 years. Is it of concern for an automotive OHV engine? Thinking that the same issue would be in play with OHV auto engines - make sure you have the static cam timing (chain) right before turning the engine over.
At least with Saitos - the cam is driven by big ole gear up front that engages the crank rather than a timing chain. You can easily blow the timing by a tooth. There's a bunch of decent threads that include good tutorials for setting the cam / crank timing.
Things that make ya go 'emmmmmm ...."