The point is that you definitely need to ensure that the cam timing is correct and that there is sufficient piston/valve clearance within the entire range of potential cam timing. Hopefully someone with a better memory or more recent experience can offer better numbers. Repeat with the cam timing advanced a couple of degrees, keep repeating until you are certain there is sufficient piston/valve clearance from at least 6 degrees advance to around 4 degrees retard.īTW, those are just numbers and I'm working from ages old memories. Reassemble with clay and test piston/valve clearance. Dry assemble the motor and find true zero for the cam timing. If not, I would suggest getting one before going any further. I'm assuming that you have an adjustable cam cog. Did the exhaust valve have plenty of clearance? If so, I suspect the cam timing was too far advanced.
