Quote:
Originally Posted by David Lien
... They advised me that the .008 on the intake valve lash was indeed correct, and happens many times with a reground Cam. It has to do with the smaller base Circle and the valve timing. The support person was fun and educational for this old fellow to talk with. Thanks Pete and all that answered my post. David
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Hi David,
I question the Tech's comment on a reduced base circle being the reason for the lower gap of .008"
The valves are adjusted with the each valve adjusted, gaps set, when on the "heel" of the cam. If the base circle is reduced in order to accommodate the re-grind, the gap at the heel would increase over what is was for a a standard and larger base circle. New longer push rods will be required for the intake valves unless you will be using adjustable lifters.
If the desire was to increase the valve open duration or lift, a smaller gap at the heel would do this but is not a requirement due to the reduced base circle.(Note that this is NOT a safe gap for
exhaust valves since the time the valve is seated and cooled would be decreased.)
I've never seen a Ford Flathead with an gaps less than .010" as mentioned above. see the attached chart for example. Yellow highlighting made by me in the past.
You mention that the cam came from Isky in 2008 so not that old. Did it come with a cam card?
I agree with Pete and B&S but would use .014 & .014" myself.
"Also, who knows when your particular cam was ground . . . off of what masters. I would probably use the .011 and .013 numbers that Pete gave you. Or the .012 and .014 . . . either ones will work just fine and you'll never be able to tell any difference between the two. Like TUBMAN said, I've never seem specs that called for less than .010 . . ."