Cam button use

Mark Barnes · Jun 22, 2021

I just read a thread about a cam walking out and causing major damage to a fresh engine. Feel bad for the poster.
My question is, how many members think a cam button is necessary, and actually use one? I have a new motor I'm just buttoning up, and this made me think...

Mike67 · Jun 22, 2021

Mark Barnes said:
I just read a thread about a cam walking out and causing major damage to a fresh engine. Feel bad for the poster.
My question is, how many members think a cam button is necessary, and actually use one? I have a new motor I'm just buttoning up, and this made me think...

I think you are referring to my post, the engine damaged one, and another thread posted about buttons not being necessary on a BBM due to the cut of the intermediate shafts gear.
When I read that post I saw the logic in it but decided to go with the instructions and majority concensus.
I had to use a nylon bushing as roller type would not fit with the cam bolts and was larger than the bore on the gear drive. I measured everything twice and was confident about the clearances, but I guess I may have hit the button when installing the cover causing it to fall out of place, Which allowed the cam bolts to make contact with the aluminum cover and send chips everywhere.

gkent · Jun 22, 2021

The cut of the gears and direction the cam rotates should hold the cam in place. As well, on solid or hydraulic cams, the angled lobe will also drive the cam towards the rear of the block. Despite all that, it appears cams do walk enough to cause potential damage so a button is not a bad idea. HOWEVER, fitment is critical. You absolutely want a few thou clearance between the button and the timing cover or you run the risk of galling the timing sprocket and the block at the contact face (ask me how I know !!). Do NOT use an aluminum button - these will definitely gall up and spew **** into the motor if they make any contact with the cover. As for the bolts chewing into the cover, I have no idea what Mike67 used BUT you definitely want to use bolts with a short head and you won't find those in your local Home Depot. Lastly, you will not find an "off the shelf" button that fits without some tinkering. If the button is too short you can space it out with pieces of feeler gauge behind it. If its too long you can use thicker timing cover gaskets or if its a nylon button you can grind it down.

Don Frelier · Jun 22, 2021

My understanding is you need to use one with a roller cam as the lobes are not tapered to spin the lifters and drive the cam towards the rear of the engine a true "bumpstick".

gkent · Jun 22, 2021

Don Frelier said:
My understanding is you need to use one with a roller cam as the lobes are not tapered to spin the lifters and drive the cam towards the rear of the engine a true "bumpstick".

But the gears should prevent forward motion - just try to pull the cam out with the intermediate shaft installed !!

IQ52 · Jun 22, 2021

Yes I'm a complete hack but I use a cam button on every big block MOPAR roller cam installation I do.

Don Frelier · Jun 22, 2021

IQ52 said:
Yes I'm a complete hack but I use a cam button on every big block MOPAR roller cam installation I do.

Can you educate us on what type of cover to use?
I would think the stock cover might not be stiff enough as it's just made to hold oil.
I'm thinking this would be a job for an engine builder and maybe not a good idea for a guy in a garage.

IQ52 · Jun 22, 2021

Don Frelier said:
Can you educate us on what type of cover to use?
I would think the stock cover might not be stiff enough as it's just made to hold oil.
I'm thinking this would be a job for an engine builder and maybe not a good idea for a guy in a garage.

MY feeling is.....If I cannot afford this timing cover, I cannot afford a roller cam..................

http://arengineering.com/products/timing-chain-cover/

Others will disagree and offer various options.

1 Wild R/T · Jun 22, 2021

IQ52 said:
MY feeling is.....If I cannot afford this timing cover, I cannot afford a roller cam..................

http://arengineering.com/products/timing-chain-cover/

Others will disagree and offer various options.

I can afford the cover, I just prefer my engine look stock... after the timing cover has been installed & the cam thrush finalized put masking tape over the center of the timing cover then mix up a blob of JB Weld & put it on the tape... Now bolt on the water pump.... The JB Weld when it hardens will keep the cover from moving & the tape will allow the water pump to be removed later... Now we know who the real hack is.... But if it works is it really a hack???

zyzzyx · Jun 22, 2021

Sorry Guys, a cam button is fer the Chevy guys, NOT Mopar! No way, No How.
In an earlier post I went into great detail about this misinformation. We have
enough to do on our cars without wasting time on frivolous modifications.

66Satellite47 · Jun 22, 2021

I used cam buttons on my drag motors late '70's thru '80's with big solid flat tappets, Mushrooms & several rollers. I used the Cloyes roller button. It was evident that there was enough cam walk to justify it. I did reinforce the stock timing cover with a piece of 1/8" flat stock welded to the outside of the cover. Worked great. Did take some work for proper fitting for the cam and the water pump.

Don Frelier · Jun 22, 2021

zyzzyx said:
Sorry Guys, a cam button is fer the Chevy guys, NOT Mopar! No way, No How.
In an earlier post I went into great detail about this misinformation. We have
enough to do on our cars without wasting time on frivolous modifications.

So you prefer unbuttoned?

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zyzzyx · Jun 22, 2021

Yes Sir! I sure do!

O.K., so if the cam is moving forward, what is happening to your timing?
The intermediate shaft doesn't shear off?
The 45 degree cut gears keeps the cam firmly planted on the thrust face at all times.
Mike67 has his engine apart right now, and as he puts it back together again he can let us know what he finds.
We all hope that his damage will be minimal, and back running shortly!

66Satellite47 · Jun 22, 2021

I also used the thrust washer between the block & timing sprocket. Usually the Torrington bearing style.

diesel_lv · Jun 22, 2021

I won't go into whether a BB Roller cam can or can't push forward. I "have" heard of it happening and as "very" cheap insurance, I use a nylon button on my roller cam. I use the 440 Source timing cover, it is a thicker guage steel recommended by them for roller cams and looks factory. I also shim under my distributor to avoid any shaft rise and change in timing.

Lefty71 · Jun 22, 2021

Here's my Neanderthal take; I built motor with Roller cam.... I used cast front cover, cam button and bushing (not Torrington)...... motor went fast, never looked back. The End. Thx, Lefty71 :carrot:

Don Frelier · Jun 22, 2021

Beekeeper · Jun 22, 2021

IQ52 said:
MY feeling is.....If I cannot afford this timing cover, I cannot afford a roller cam..................

http://arengineering.com/products/timing-chain-cover/

Others will disagree and offer various options.

I used the cover from AndyF and it’s important to me that my engine uses stock external components and looks stock but i wanted to use a cam button on the roller cam. The cover is barely even visible once the pump housing and accessories are installed. I painted the cover along with the engine as well don’t let the price scare you this is one fine piece and factory water pump housings clear it with no grinding.

IQ52 · Jun 22, 2021

Got a call from another engine builder about six months ago. He had a cam button with a roller cammed big block Mopar on the dyno and said to me, "We can SEE the stock timing cover BULGE and the timing won't hold steady. What can I do?"

AREngineering timing cover says I.

A few days later he calls and says, "Thanks, timing is steady and that cover isn't going to move."

zyzzyx · Jun 22, 2021

So, while we were taking a break, I made a call to Keith Black Racing and talked to the Head of Operations.
Asked if he'd ever built a Mopar Big Block. Oh Boy! Yes, he said. About 1500 or so! O.K., so have I got a
question for you! He said that NO Big Block they have ever built had a cam button because they don't need
one. We had a lengthy conversation about the problem of misinformation, and he said he did not know how
this started. I'm not trying to bust anyone's Balls, but just trying to clear up the B.S. If any of you still don't
believe this is a true statement, please get someone of great importance to back your claim up so we can all
learn something. I've been wrong in the past, and I'm done yet!

Cam button use

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