Ford flathead adjustable mushroom lifters mystery.

Ronnieroadster

Ronnieroadster

Well-known member
Recently came across some adjustable mushroom lifters for a flathead I had never seen before. Wondering if anyone knows anything about them.
 

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I don’t think it’s active anymore, but the mid-Atlantic stock car racing website had a ton of info on different liters and which cams used them. Let me see if I can find it and I’ll post it here
 
Ronnie are they one piece or is the flat bottom lifter surface added to the hollow adjustables?
 
Bored&Stroked said:
The wider face allows a more aggressive opening ramp that uses the additional width to open the valve faster/sooner.
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Thanks Dale, I get how that would happen. Would these lifters be used in conjunction with a performance/high lift cam, or are they a less expensive alternative to an aftermarket cam? I hope I'm not asking dumb questions, it's just that the workings of valve trains is a really interesting subject to me.
 
GB SISSON said:
Thanks Dale, I get how that would happen. Would these lifters be used in conjunction with a performance/high lift cam, or are they a less expensive alternative to an aftermarket cam? I hope I'm not asking dumb questions, it's just that the workings of valve trains is a really interesting subject to me.
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They are definitely something specifically designed for a cam whose lobe design needs the broader face. If you put them with a cam not designed for them, you'd achieve nothing as no part of that extra diameter would be touched/used.

Mushroom profiles were something that certain cam grinders used to create more aggressive profiles before roller-lifters became the thing. Once roller lifters took hold, my guess is that almost nobody created mushroom profiles since.

Just think about how much fun it is to install and service them! You have to pull the whole damn lower-end down (on a flathead Ford) - just to get to them.

Back in the late 30's, there were companies like Chrysler, Studebaker, Cadillac, etc - that used mushroom lifters in a lot of their engines. I've retrofitted some of these for Bonneville engines (prior to going to roller-lifters)

Radius Lifters: Some folks like Isky created radius lifters - which in a sense are kind of a baby-step towards roller lifters. The big radius on a non-rotating lifter allowed more aggressive profiles and ramp speeds to be used. The big issues there are having to index the lifters, premature wear, etc.. While we like to talk about Isky's 404A radius cam (and others - Crane, etc), the usage of these lifter designs was quite limited and not popular at all with street driven vehicles.
 
pistonbroke said:
Just curius , would you call the ford Y block lifter a mushroom type? Tim
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Yes. Whenever the face that rides on the cam is larger than the body, it is a mushroom lifter.

This wasn't always done for performance reasons; in older engines it was quite common (until the 50's that is). Why Ford used this style of lifter on the Y-Block - I have no clue. (Knowing Ford - probably to save money!).
 
When it comes to the Y block Ford engine I'm sure there's been many who discovered the hard way about those lifters. Many would assembly an engine by installing the crank and piston rod assembly's. Then next add the lifters and bolt on the head's. On the Y block if you don't put the lifters in first there's a big surprise its impossible to install them once the lower end has been installed.
Ronnieroadster
 
pistonbroke said:
Ronnie were you spying on me 40 years ago when I was building my 55 hardtop? Thats what I did to the letter. Tim
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That's to funny but i bet way back then it was not funny at all.
Tim I'm sure you were not the first or last to do that. Most would never admit doing such a thing but IM sure its happened many times and possibly still happening at times.
 
Bottom line, a cam profile is designed to run on a lifter of a certain diameter. If a cam is designed for a 1" lifter and you put in a 1.25" lifter, it will not do a dang thing. It will contact the 1.25" lifter at the same diameter and same way that it does a 1.00" lifter.

The only case where this is not true is if the cam profile "runs off the edge of the lifter" - which it should not really do (if designed correctly). On the original Potvin 425 cam, it DID run off the edge of the lifter a bit (which is hard on the cam and lifters). If you've ran one for a while and take a look at the outer edge of your lifters, you'll see what I mean.

I was in contact with Harvey Crane before he passed and he mapped my Potvin 425 on his machine and used his super-sophisticated computer program to rework the profile, so it didn't run off the lifter edge. We were going to regrind a new version of the Potvin 425, but as life/luck had it . . . Harvey passed away. The super-bad part of this story is that my original Potvin 425 went to the grave with him! Argggghhh

Harvey was a super good dude and had a lot of good stories to tell about the "cam wars" back in the day, how he and Ed Isky got along (and did business together), etc.. I miss both of those guys!
 
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