Potvin cams

[3W Hank]

I has a question over the Potvin 425 eliminator cams.
I came over to see a cast 8AB marked POTVIN, and under was stamped 425.
I read some on it and if I got it correct he did both 32 steel core and cast and also welded cast ones.
But good sources tell me Potvin always used the 32 cores and grinded journals 010.
The one i saw had std journal diameter and cam was rather thin at core and lathed. Nice works.
Maybe several made copy of this cam and called it ’Potvin 425’.
-Maybe it was the same era or in the 50’s, 60’s or 70’s ?
Pretty shore this cam is not recently grinded.
But good ol information to know as FH race history.
Maybe some has more information.
Thanks.

[petehoovie]

[Bored&Stroked]

The original Potvin 425 Eliminator cams were usually done on billet steel 32 cores - with the bearing journals done to .010 undersize. The undersize journals were usually done because in 32 there were no cam bearings in the block - so the cam just ran on the cast iron. Due to this, an older cam might be worn a bit in the journals - so .010 made sense.

Given how small the base circle needed to be to achieve .425 lift, Potvin felt the 32 cores were better than cast cores. Also, some believed that the steel cam would last better than a cast one - as the Potvin 425 profile has a sort of "point" at the top. This is the only Potvin cam that has that lobe profile that I've seen.

I had a 425 that was ground by Bill Jenks at Moon - it was a cast core cam that had the tops of the lobes welded up. What I don't know is . . . was that done to achieve the lift needed, or was it done to make the top of the lobe last longer. I never had a chance to ask Bill the reason.

I recently had "Pete" regrind a 32 core with the Potvin 425 profile. It still has the original "press on" type of gear on the front - which actually makes setting the cam timing easy.

[Pete]

Originally Posted by Bored&Stroked

The original Potvin 425 Eliminator cams were usually done on billet steel 32 cores - with the bearing journals done to .010 undersize. The undersize journals were usually done because in 32 there were no cam bearings in the block - so the cam just ran on the cast iron. Due to this, an older cam might be worn a bit in the journals - so .010 made sense.

Given how small the base circle needed to be to achieve .425 lift, Potvin felt the 32 cores were better than cast cores.

> Actually the base circle of the 425 is very close to many of the popular
performance cams of the day. The main difference was the Potvin's were
"swept ground" instead of relieving the core. This was primarily a cost saving
operation. It has no affect on operation.

Also, some believed that the steel cam would last better than a cast one - as the Potvin 425 profile has a sort of "point" at the top. This is the only Potvin cam that has that lobe profile that I've seen.

I had a 425 that was ground by Bill Jenks at Moon - it was a cast core cam that had the tops of the lobes welded up. What I don't know is . . . was that done to achieve the lift needed, or was it done to make the top of the lobe last longer. I never had a chance to ask Bill the reason.

> I have redone quite a few of those cast original 425's and the discoloration
was heat treating, not welding.


I recently had "Pete" regrind a 32 core with the Potvin 425 profile. It still has the original "press on" type of gear on the front - which actually makes setting the cam timing easy.

...

[3W Hank]

Here is the cam I saw.
No marking on eliminator but surface is smaller, instead a ’E’.
Could it be a Potvin early 50’s or a copy.
I can’t say.

[petehoovie]

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Originally Posted by 3W Hank

Here is the cam I saw.
No marking on eliminator but surface is smaller, instead a ’E’.
Could it be a Potvin early 50’s or a copy.
I can’t say.

[KiWinUS]

Originally Posted by 3W Hank

Here is the cam I saw.
No marking on eliminator but surface is smaller, instead a ’E’.
Could it be a Potvin early 50’s or a copy.
I can’t say.

Have you measured the lift? I have two originals and neither has .425” lift. I am led to believe none had exactly.425”.
I also have had a master made off one of my originals.

[Pete]

Originally Posted by KiWinUS

Have you measured the lift? I have two originals and neither has .425” lift. I am led to believe none had exactly.425”.
I also have had a master made off one of my originals.

I have had 4 original steel ones pass through my hands.
All had .416 lift.

[3W Hank]

I might can has it in a camdoctor, if so I will show it.
I could get a 32 core, as I will found one, I might also can make a billet but to my project it don’t fit the ideas.
Will a cast old one works, I guess so but a steel one is better plus the cool factor ( thats might sound odd )
I has a Scintilla in a 8AB camcover but a 59BA block.
The case get the 32 core it need some works beside the grind.
-If anyone had a good Mooneyes to sell keep me posted.
That fit my build up ideas perfect.

[40coe]

You may want to contact schneider racing cams in San Deigo. Gerry Cantrell not sure I spelled his name correctly?
He has been doing this a long time and offers a Potvin grind

[3W Hank]

Idea is history and I want first choice a old 32 core cam from Chucks machine, but if I grind one it will be on AB core and Pete1 will do that.

Some here must has a cam so I hope some read this..

[3W Hank]

Got this cam in position, its straight and lift is around 424.
Cant see any issues but some tips has angle, se picture where screwdriver points, some is not.
Hard get a 32 core plus machining and a AB adapter.
If a old Chuck’s its cool to my car.
Will has it in a camdoktor.

[petehoovie]

Originally Posted by 3W Hank

Got this cam in position, its straight and lift is around 424.
Cant see any issues but some tips has angle, se picture where screwdriver points, some is not.
Hard get a 32 core plus machining and a AB adapter.
If a old Chuck’s its cool to my car.
Will has it in a camdoktor.

[3W Hank]

I heard a story on Potvin cams in Sweden on late 50’s or early 60’s.
A Sweden pioneer hotrodder had 32 roadster was running 4 Strombergs and Potvin cam.
They sended heavy 32 axles to US for dropp and they was running their cars hard and long trips.
That story show that it was possible get a Potvin cam even after 48 or as late as late 50’s.
If Chuck still was the boss or made cam’s I can’t tell but they did like Potvin.
What I might think, why was Chuck so into the 32 cores, as they must be hard to find even in the 50’s.
If, I’ll just think why not grind the 425 on the 8AB’s, as to me it make sense.
I might be wrong.
-Just a idea after I heard this story.

I read on Potvins company that cams got so cheap in the 60’s so he could not get a core from others sold a cam at, so he went out of buseniss or sold the company.

https://kustomrama.com/wiki/Lennart_...%27s_1932_Ford

[Tim Ayers]

Hank

Do not get hung up on stalling your project in order to find an original Chuck Potvin ground cam. My 3/8ths was ground by Bill Jenks @ Moon in the early 2000's. I would not hesitate to run a Potvin ground by Pete, Kiwi Tony or from Schneider cams.

[3W Hank]

Ah, so Jenk made cams so late.
Good info, did he mark the ’POTVIN’ ?
-Well my coupe is try be a time machine based on as much Henry and old speed parts as possible.
The cam I showed and asked history on, I has now.
I was kind of wanted a 32 core for several resons.
I was not really into a cast core but this got to be now.
I’m open on get a 32 cam ( original 40’s ) or grind a new aswell.

[Tim Ayers]

Originally Posted by 3W Hank

Ah, so Jenk made cams so late.
Good info, did he mark the ’POTVIN’ ?
-Well my coupe is try be a time machine based on as much Henry and old speed parts as possible.
The cam I showed and asked history on, I has now.
I was kind of wanted a 32 core for several resons.
I was not really into a cast core but this got to be now.
I’m open on get a 32 cam ( original 40’s ) or grind a new aswell.

Yes, Bill Jenks worked for Dean Moon at Moon. The cam is marked Potvin on the snout with the grind, in this case, 3/8ths. Talking to Bill was quite a treat and he was a real gentleman. Asked me the relevant questions and then replied that he ran a 3/8ths in his roadster back in the day.

When I sent him the core, he called me about a week later to remark how nice the core was and it had been many years since he saw a wide lobe 59AB core come through the shop. I feel like I also have a piece of hot rod history by having it done by him.

[3W Hank]

So from what you see this cam I show could be a Bill Jenk work sometimes in the past.
If so that is cool.
A question, you mention wide lobe 59BA, was that all 59AB or just some cams ?
If I grind one I has a very nice 59AB ( I can mesure lobe diameter ) but a odd thing on that cam is the all 3 journals is not 1.7955” but 1.7920” ( a odd number on undercut even from Ford, as I had heard on -0.002” )
The old Sweden hotrodder on the 50’s my guess used the 3/8 cams, not the 425.
Great to know history.
I read a book now on all the speed legends.
It’s a picture on Bill Jenks in his roadster under the chapter Chuck Potvin.
I also seen the ’Potvin roadster’ someone restored.

[Ronnieroadster]

Originally Posted by 3W Hank

So from what you see this cam I show could be a Bill Jenk work sometimes in the past.
If so that is cool.
A question, you mention wide lobe 59BA, was that all 59AB or just some cams ?
If I grind one I has a very nice 59AB ( I can mesure lobe diameter ) but a odd thing on that cam is the all 3 journals is not 1.7955” but 1.7920” ( a odd number on undercut even from Ford, as I had heard on -0.002” )
The old Sweden hotrodder on the 50’s my guess used the 3/8 cams, not the 425.
Great to know history.
I read a book now on all the speed legends.
It’s a picture on Bill Jenks in his roadster under the chapter Chuck Potvin.
I also seen the ’Potvin roadster’ someone restored.

Since all three journals measure lower than the Ford dimension its simply a worn cam. If a cam that measures worn is used for a profile change its simple for the grinder to go to a .010 undersize then we simply use new .010 undersize cam bearing's.

Years ago {the last century} Isky usually ground the cam journals under size along with a reground profile but failed to inform anyone the small detail about the bearing size. Many a builder found out the hard way when installing the Isky cam in the now installed standard size cam bearings. That's a big pain when the crank and rods have been installed now everything has to come back out to change the cam bearings.
Ronnieroadster

[deuce lover]

32 Cam just listed for sale on the HAMB

https://www.jalopyjournal.com/forum/...-sale.1311929/