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Bored&Stroked · 08-13-2019, 07:50 PM

Reason for wearing out: Can be many things (like material/alloys of the lifters, etc). What you should ponder is the overall SIZE of the flathead performance profile . . . has a LOT less surface area (if you traced the path/length of a lobe) than a modern OHV engine and a much smaller base-circle - so you get more flex in the cam as well - which also wears things faster. Another thing to think about is that flatheads don't have rocker arms - so when you have a higher lift cam like a .425 Potvin, this would be .637 lift on a simple 1.5 rocker. So, to get higher lifts on a flathead, the profile has to be pretty aggressive . . .which also leads to more wear.

08-13-2019, 07:50 PM	#3
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,067	Re: FH Valve Springs Reason for wearing out: Can be many things (like material/alloys of the lifters, etc). What you should ponder is the overall SIZE of the flathead performance profile . . . has a LOT less surface area (if you traced the path/length of a lobe) than a modern OHV engine and a much smaller base-circle - so you get more flex in the cam as well - which also wears things faster. Another thing to think about is that flatheads don't have rocker arms - so when you have a higher lift cam like a .425 Potvin, this would be .637 lift on a simple 1.5 rocker. So, to get higher lifts on a flathead, the profile has to be pretty aggressive . . .which also leads to more wear.