The Ford Barn - View Single Post - I’m rebuilding my first Flathead and I have some questions

drolston · 07-20-2021, 10:41 PM

With mechanical lifters (not hydraulic) there must be a specific gap between the lifter sitting on the heel of the cam and the bottom of the valve stem. That clearance is there when the engine is cold, so that when the valves get hot and grow a little longer, there is still enough gap that the valve will completely seat. Too little gap and the valves may not seal, and leak and/or burn. To much gap, and the valves will be quite noisy, and will not open as far as the should. The gap between lifter and valve stem end should be about .014 on intake valves and about .016 on exhaust valve.

Get a good flathead engine book before you go too much further. Folks on this site will recommend the good ones

07-20-2021, 10:41 PM	#2
drolston Senior Member Join Date: Jun 2014 Location: Williamsburg, VA Posts: 1,627	Re: I’m rebuilding my first Flathead and I have some questions With mechanical lifters (not hydraulic) there must be a specific gap between the lifter sitting on the heel of the cam and the bottom of the valve stem. That clearance is there when the engine is cold, so that when the valves get hot and grow a little longer, there is still enough gap that the valve will completely seat. Too little gap and the valves may not seal, and leak and/or burn. To much gap, and the valves will be quite noisy, and will not open as far as the should. The gap between lifter and valve stem end should be about .014 on intake valves and about .016 on exhaust valve. Get a good flathead engine book before you go too much further. Folks on this site will recommend the good ones