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Discussion Starter · #1 ·
Posted "elsewhere." Just thought I'd pass it along. Been wondering about the cam-block thrust surface on my Stage 2.


Roller Cams (Please Read)

I have some information that anyone who has installed a Billet Roller cam base on the
DIY parts list I posted 3 years ago. Over the last week I have received 2 e-mails from
guys who have had a wear problem apparently caused but the billet roller cam. One
car has 9,000 plus miles and the other has 7,500 my own car has over 28,000 miles all
with a billet roller cam. The fellow with 9,000 miles had a chain tensioner fail and when he removed the cover to replace the tensioner found that he had wear on the cam
thrust on front of the block. Wear he indicated was around .087. The second guy had a lifter cross bar fail and found he also had wear on the front of the block no determined amount at this time as he is removing the motor because of lifter failure. Since these
e-mails I have called anyone I know who was replacing their cam who had a billet
before and asked them to check for wear. They found anything from no wear to just a
couple .001. I have 28,000 + miles on my motor and have no idea if there is a problem
but will know in a couple weeks. If you have a DIY roller and have not installed it do
not install it. For those who have not installed the roller cam yet I will post what needs to be done to prevent this problem. At this time Weber will machine your parts for the BB chev roller thrust. I will post exactly what it will take to do this if you have a local machine shop to do it for you. It will take me a few days to put together the correct info. For those that have installed already, if it’s a low mileage car I have not seen a problem. High mileage car daily driver type is where this problem has raised its ugly head. This is not meant to start a panic but to inform. Like I said I have only heard from 2 guys with this problem but everyone needs to know. You can check to see if you have a wear problem using the following method. Its not exact but it will work.
Remove the cam sensor and take a screw driver and move the cm drive front to back
and so on. If you cam endplay has opened up you will know. I am also working on a fix for those who may have wear on the front of the block I will post that info in just a few days. Sorry for this information but I wanted everyone to know. Subscribe to this post as I will post any updates.

Lonnie Diers

Last edited by quickt on July 28th, 2001 at 02:39 PM
 

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It looks like the old roller bearings against cast iron thing is rearing it's ugly head again.At least Lonnie was stand up enough to tell somebody about this.can't fault him for that.Once the engine is out,it should be a simple fix to machine the thrust face on the block for a steel bearing race.I would be sure to check all the bearings and lifters,etc. for cast iron silt and the attendant scoring.Again,thanks for the heads up.I was thinking about putting together a roller package Lonnie suggested and wondered about the thrust on the front of the block.*Maybe* it would work due to less pressure on the iron.However,it looks like my suspicions were confirmed.At least the guys got a heads up.Good work.

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Give em' hell!

[This message has been edited by The Radius Kid (edited July 29, 2001).]
 

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I haven't seen their setup yet.Can you tell me what they did about front thrust?Rear Thrust?

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Give em' hell!
 

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Discussion Starter · #5 ·
Oh, yeah. BIG time kudos to Lonnie for getting the word out. Hope he reads this board, too. I'd have thanked him, but I don't post to the other board anymore.

I was a bit worried about this too, having set up my Stage 2 with a billet roller. On the other hand, note that Lonnie states that this is mostly a problem for daily drivers...although I think that translates to "only a matter of time." Radius, I got the impression that the problem was the steel cam flange wearing against the block face WITHOUT a bearing. Now, I'm running a RPM rear thrust set-up, and NOT a spring-loaded thrust bumper against the front cover. I wonder if that will alleviate the situation... that is, not having a spring pushing the cam back against the block face at all times?
 

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Yep,I would think that the rear roller setup would be better than the front thrust button.I still like the idea of the regular cam thrust instead of the roller for front thrust.Should work just dandy provided it's got proper lubrication.For some reason I get visions of wiped cam lobes when I think of a roller element running against cast iron.Call me quirky.

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Give em' hell!
 

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Originally posted by The Radius Kid:
Call me smirky.


Why don't you and Zap play your games in private!?

 

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Give me the low down here. Are we talking about those who use a spring loaded cam button on the front of the cam? If so, are those same people using a thorington type bearing between the block and the cam? Or... are they bearingless between the block and the cam? Thanks Craig
 

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I'm not realy shure if this will help but I took some measurements......

ATR billet roller bought about 2 years ago. 214/210.

The surface just forward the #1 cam bearing has been machined .125 inward. The outter diameter of the new surface is 1.826.

They used a brass thrust washer .100 thick, inner 1.855, outter 2.635.

They use a spring/button set up on the nose of the cam.

I just purchaced a Crane 214/210 and when looking at the thrust surface on the cam, something didn't look correct. To me, the cam looks like if it comes into contact with the block your going to get wear. I think I'm going to follow suit like ATR except I think I'll try to find a thorington style bearing instead of the thrust washer. I measured a thorington today that was used on a stock cam that at one time or another had a cam eat the block. The thorington measured in at about .875 thick so the new cam doesn't need to be ground as much, now to find out if a small block chevy bearing diameter is about the same as a buicks? HTH Craig
 

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I got to thinking about that cam against block thing today,and to be honest,I've got to agree with ATR about the bronze thrust washer between the cam and the front thrust face on the block.This removes the similar metals from contact each other and galling.Good idea.As to using a Torrington roller thrust bearing for the front thrust load between the cam and block,I wouldn't.We've already seen how good cast iron works when a roller rides on it.How well do you think it'll stand up to a bunch of little needles?if you're contemplating using a full roller thrust bearing with front and rear races as well[similar to the rear thrust kits],that could work well,but will involve some machining of the cam to get the fromt distance right.But then I guess any deviation from cam to block front thrust will.Choose your poison.
Steve,go sit on a cactus.


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Originally posted by The Radius Kid:
As to using a Torrington roller thrust bearing for the front thrust load between the cam and block,I wouldn't.We've already seen how good cast iron works when a roller rides on it.How well do you think it'll stand up to a bunch of little needles?
I talked to Dave Weber today about the torrington thrust bearing. I guess it's got integral races, ie the rollers don't touch the cam or block, but rather the outside of the races touch the cam and block, and they don't spin, in theory.

FYI this is what Lonnie is talking about when he says the cam needs to be sent to Weber to be machined (you can do this yourself too, I'd guess), to make room for the bearing in the assembly.


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John Martin

83 Hurst/Olds
86 T-Type
 

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Well,if you need a thrust bearing in there,I guess that would be the way to do it.

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Give em' hell!
 
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