Technical flathead lifters

Do flathead lifters rotate in the bore?

 

Only when the engine is running!

 

removed solid lifters and the bottom wear pattern showed no rotation.

 

I seem to remember reading somewhere that lifter rotation is more a function of the cam lobe design than that of the lifter.

Ray

 

partial rotation is what the wear pattern shows
, can they be resurfaced

 

Unless they are adjustable lifters you may be better off just to spring for a new set. When resurfaced they will be shorter. As you may know, flathead valves were fitted for proper lash clearance by grinding the base of the stems.

I supppose new valves could overcome this potential problem, but given the time consuming nature of grinding the stems to fit, new adjustables could be well worth the investment.

Ray

 

These are adjustable lifters

 

well then, looks like you are halfway home. I am not sure where one would go for regrinding, but suppose a good place to start would be an automotive machine shop..Also, aircraft machine shops routinely resurface cam followers...might be another source to check.

Ray

 

Thanks for tne info, will start calling local shops and see if they can do it.

 

I believe its either a 96" or 98" radius on the flathead lifter.

 

I had my set refaced a few years ago at Delta Camshaft in Tacoma, Washington area. As I recall, it was about 3-4 dollars per lifter to get it done.
I don't have their address or phone number handy, but I'm sure you can Google it and find them. Good luck!

 

There is a gentleman over at the ford flathead V-8 site that ground a set for me. His name is John Lawson and he just so happens to also be from Georgia. He is very knowledgable about flatheads. If interested in contacting him, give me a pm.

 

I know him, I live close to him, I will give him a call. Thanks

 

Having original Johnson’s restored / ground IMO is preferred to buying new / they don’t make um like they use to applies here.

 

It's a combination of the two. During the camshaft manufacturing process, lobe surfaces are not ground parallel to the camshaft centerline, but are ground at a “rake angle” which is usually somewhere around 1 degree. Also, the lifter base, or foot, are not ground flat, but has a spherical radius, or is ground convex. Back in the 70's when I was a little closer to this type of machine work, I believe Ford used a 30” radius on their flat tappet motors, not sure if the flatheads were the same. RB35 says above that it is a 96 or 98 inch radius, which is significantly flatter than a 30" radius. The radius used varies somewhat from manufacturer to manufacturer. At first this sounds odd because one would think that pressure between the lobe and lifter would go up as the contact area is reduced. However, this machining ensures a reasonable and predictable contact pressure within practical machining tolerances. The lifter foot radius and lobe rake angle guarantee a good cam to lifter contact area which also imparts rotation to the lifter, giving better cam and lifter life.

 

I've seen the numbers in the nineties quoted for flathead by Lawson, a man who NEVER says anything he has not exhaustively proven, tested, and documented.
Whatever it is, it is fairly hard to see when held against a flat, like lifter foot against side of another lifter.
By the way, olde valve ginders often hae an attachment for regrining worn lifters...to flat. What were the implications of this?

(a PS...I have some numbers around somewhere for early flathead valve train patent drawings. Will try to see if they discuss lifter feet. By the way, some show essentially final design of flathead valve train...but with hollow bucket style lifters! Ol' Henry did not like heavy stuff moving around. Final design used about a little iron as could be imagined in the lifter.)