Moparts

Cam Button

Posted By: barracudabob

Cam Button - 03/23/14 05:26 AM

My engine builder recommended I put a cam button on my 440. This is with a solid flat tappet cam. I have a few questions, when are they necessary? Are they installed on the cam or on the cover? How are they adjusted? Who makes a good one? This is for a three bolt cam. Any info would be appreciated, thanks in advance, Bob
Posted By: MR_P_BODY

Re: Cam Button - 03/23/14 06:24 AM

I havent built a BB in years but I've only put a
button on a roller cam.. the ramp angles on the lobes
keep it rearward... I'm sure one of the BB guys will
jump in and help you out
Posted By: therocks

Re: Cam Button - 03/23/14 01:46 PM

No need for a button.Only time is with a roller or gear drive.Like Mike said the way the cam goes in keeps it in place.Rocky
Posted By: Jerry Kathe

Re: Cam Button - 03/23/14 02:34 PM

Cheap insurance. Less than 20.00 in most cases and would save cam and lifters in the chance you would break a timing chain.
Posted By: Stanton

Re: Cam Button - 03/23/14 02:43 PM

Forget "cheap insurance", it TOTALLY UNNECESSARY unless its a roller cam! With 16 valvesprings putting pressure on the ramps of the cam it ain't gonna move forward.

And there's no such thing as a "drop in" cam button, nobody makes one that will go in and fit properly without some modification to either the button or the timing cover. And that raises another point - you need to modify the stock cover or use an aftermarket cover for the support necessary to prevent forward movement of the cam.

You don't need the button and you don't need the hassle.

But if you don't listen to our advice and insist on installing one, avoid the aluminum one's like the plague - they will gall up and little bits will fall off into the motor.
Posted By: Stanton

Re: Cam Button - 03/23/14 02:44 PM

Timing chain ??? What does that have to do with it ???
Posted By: Jerry Kathe

Re: Cam Button - 03/23/14 02:53 PM

In nearly every case the cam will jump forward and the adjacent lifters will contact the neighboring lobes.

Seen it more than once, but don’t know anybody who done it twice – lol.
Posted By: Jerry Kathe

Re: Cam Button - 03/23/14 02:55 PM

Quote:

Forget "cheap insurance", it TOTALLY UNNECESSARY unless its a roller cam! With 16 valvesprings putting pressure on the ramps of the cam it ain't gonna move forward.

And there's no such thing as a "drop in" cam button, nobody makes one that will go in and fit properly without some modification to either the button or the timing cover. And that raises another point - you need to modify the stock cover or use an aftermarket cover for the support necessary to prevent forward movement of the cam.



You don't need the button and you don't need the hassle.

But if you don't listen to our advice and insist on installing one, avoid the aluminum one's like the plague - they will gall up and little bits will fall off into the motor.


WOW....
Posted By: Stanton

Re: Cam Button - 03/23/14 04:43 PM

Quote:

In nearly every case the cam will jump forward and the adjacent lifters will contact the neighboring lobes.



Really?? In "nearly every case". Really ?? I think we need to take a poll here !!

There are hundreds of thousands of stock engines out there - wait, make that MILLIONS - with no cam buttons and the cam doesn't budge. This is with the same taper on the lobe and much lighter valvesprings than a performance cam would have.
Posted By: Stanton

Re: Cam Button - 03/23/14 04:54 PM

Posted By: MR_P_BODY

Re: Cam Button - 03/23/14 05:05 PM

I would say that 99.9% of the BB guys that run a solid
flat tappet.. or hyd cam dont use a cam button... unless
it was in there on a previous build that went from
a roller to a flat tappet....no need for it.. but
I'm a SB guy and we dont use them... at all
Posted By: qwkmopardan

Re: Cam Button - 03/23/14 05:23 PM

Mancini sells a really nice roller button. Diamond Racing Products is the brand. Cost about $30. In most engines it will fit without any mods. I have had to press an indention in a cover once or twice as it was too tight.
it is the rotation of the dist./oil pump shaft that causes the cam to try to go out the back of the block on BB mopars and sb chevys, that is why no thrust plate or button. On a sb mopar the placement of the dist./oil pump trys to make the cam go out the front of the engine, therefore a thrust plate is used. I don't know if it necessary to put a button on a BB with a flat tappet but it won't hurt to have it, however it can be a hassle sometimes. I do put them in solid lifter flat tappet cammed BB mopars that I build.
Posted By: Quicktree

Re: Cam Button - 03/23/14 05:40 PM

I have never used one
Posted By: Sport440

Re: Cam Button - 03/23/14 06:07 PM

My last performance timing and chain set that I got from Summit had a rear thrust bearing built into it at the back of the cam gear. Whether its the distributer and oil pump gear or the spring pressure on the angled lobes there is definately a force on the cam to the rear of the motor on the BB No cam button here either, ever.
Posted By: Jerry Kathe

Re: Cam Button - 03/23/14 06:08 PM

To the OP;
The cam button suggested by your builder was most likely in the form of an inexpensive safety device. In “your” application the block face carries the thrust load. The button is simply used to control travel in the case of driven load changes that create cam walk.

In the case of a broken chain at high RPM, the driven load change between the crank and cam is so rapid that it will literally try to pitch the cam OUT of the block. Even a plastic button in your case is sufficient; you can buy them for less than 15.00 SHIPPED!

Your engine builder is looking out for your best interest…….OR………you could listen to keyboard builders and simply use the option to forgo the button. But food for thought – if your technical adviser uses an aluminum button and suffers “avoid the aluminum one's like the plague - they will gall up and little bits will fall off into the motor” – syndrome, then your may want to use a different resource - I don’t know, just a guess…
Posted By: AndyF

Re: Cam Button - 03/23/14 08:26 PM

I designed a cam button assembly to work with the billet timing chain covers that I make. This setup is designed for roller cams but will work with flat tappet cams also. The center section can be removed for inspection and/or cam timing adjustment. Most folks don't need parts like this but they do make life easier if you're building serious race engines.

Attached picture 8085479-button2.jpg
Posted By: B G Racing

Re: Cam Button - 03/23/14 08:38 PM

Get the teflon Comp Cam button for use with stock style chains and gears and stock timing covers.They are easy to cut down and trim for fit.They eliminate the chance of metal against metal issues and the more elaborate multiple piece buttons that can fall apart and cause other issues.
Posted By: CHAPPER

Re: Cam Button - 03/23/14 08:55 PM

Quote:

Get the teflon Comp Cam button for use with stock style chains and gears and stock timing covers.They are easy to cut down and trim for fit.They eliminate the chance of metal against metal issues and the more elaborate multiple piece buttons that can fall apart and cause other issues.



Posted By: MR_P_BODY

Re: Cam Button - 03/23/14 09:30 PM

Quote:

I designed a cam button assembly to work with the billet timing chain covers that I make. This setup is designed for roller cams but will work with flat tappet cams also. The center section can be removed for inspection and/or cam timing adjustment. Most folks don't need parts like this but they do make life easier if you're building serious race engines.



I like that set up Andy... the eccentric for changing
the cam timing is nice even with the little marks
on it... thats one time that I wouldnt mind being
a BB guy
Posted By: fourgearsavoy

Re: Cam Button - 03/23/14 11:23 PM

I have wondered the same thing because when I removed my timing cover for the winter inspection I can see where the cam bolts were rubbing on the stock timing cover.
I'm just going to use that plastic one that BG recommended because what could it hurt
Gus

Attached picture 8085735-rearviewsavoy.jpg
Posted By: 383man

Re: Cam Button - 03/24/14 02:00 AM

I have never used a cam button on any flat tappet engines and cant say I know anyone who has. I have not had any problems or efidence of the cam gear or bolts hitting my cover. Ron
Posted By: mickm

Re: Cam Button - 03/24/14 03:46 AM

Quote:

Get the teflon Comp Cam button for use with stock style chains and gears and stock timing covers.They are easy to cut down and trim for fit.They eliminate the chance of metal against metal issues and the more elaborate multiple piece buttons that can fall apart and cause other issues.



that's the one i used...
Posted By: B G Racing

Re: Cam Button - 03/24/14 12:18 PM

The long and short of it is a hyduralic cam always have the lifters riding on all the lobes and always have spring pressure applied to all the lobes.This keeps the cam centered.Solid flat tappet and roller tappets have a specific clearence and only some of the lifters contact the cam at given intervals and use higher spring pressures.With the loading and unloading the cam wants to migrate forward with the rotation.This can cause unusual wear on a chain or gear drive as well as distributer/oil pump drives.Cams like small block mopars have a plate to hold the cam and don't require a button,but it a must for BBs.
Posted By: Stanton

Re: Cam Button - 03/24/14 07:07 PM

Quote:

I can see where the cam bolts were rubbing on the stock timing cover.



The first thing I'd be looking at is the length/thickness of the bolt head as that could be the issue. I've had allen head capscrews that hit the cover on install and had to use bolts with a thinner head. Just a thought before you assume the cam is walking.
Posted By: B G Racing

Re: Cam Button - 03/24/14 08:18 PM

Quote:

Quote:

I can see where the cam bolts were rubbing on the stock timing cover.



The first thing I'd be looking at is the length/thickness of the bolt head as that could be the issue. I've had allen head capscrews that hit the cover on install and had to use bolts with a thinner head. Just a thought before you assume the cam is walking.




We recommend always checking the cam bolts for clearence at the cover even if you use a button.We almost always find most need the heads trimmed down.
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