Cam button spring tension

[DCG]

I have the melling roller tip spring button ,cb100 I think, with a factory cam and timing cover. When I put the timing cover on the engine the spring tension is strong. The cover starts on the dowels but I have to push it down the last 1/2-3/8 inch and hand tighten the bolts to hold it down. I have to chalk my engine stand wheels to stop it from moving when I do this. This doesn't seem right. Like it will put to much pressure on the cam into the back of the block. I put the timing cover on without the cam button and it fit fine. I also tried a different cover with the original cam button and had the same problem of having to push it down. Both cam buttons stick out of the cam 3/4 of a inch. Any one run into this before? Seems like the springs should be weaker.

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[Nick Micale]

Sounds normal to me as I have installed many of these over the years.

 

[turbodave231]

Cover go on OK without the spring and button?

 

[DCG]

Covet fits good without the spring.

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[GNONYX]

You might want to grind down the metal tip on the timing cover where the flat surface of the button rest or rides on.

 

[turbodave231]

You should not need to take material off the cover on the cam thrust surface unless it is grooved from the previous button. Re-surfacing is best done on a mill, not by hand with a grinder. This surface needs to stay parallel with the front of the block.

 

[DCG]

I don't plan on grinding it at all. the roller button is smaller than the stock one so it fits in the mark
I guess the spring tension I'm talking about is normal. Does the slant cut on the lobes for the lifters to spin make the cam want to push forward?
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[turbodave231]

There is a taper ground on to each lobe of the cam (on flat tappet cams only). Every other lobe is ground in the opposite direction. The net effect is the cam "should" not walk forward or backward in the block. There is often a little bit of thrust that makes the cam ride forward.

 

[GNONYX]

You should not need to take material off the cover on the cam thrust surface unless it is grooved from the previous button. Re-surfacing is best done on a mill, not by hand with a grinder. This surface needs to stay parallel with the front of the block.

If you read what I said it didn't say anything about grinding the down the timing cover.
My experience when I replaced the timing chain, where the original cam button rested on created a little tit or point in the center, causing the replacement cam button to move side to side or wobbly. So I grind down the tit or point so the whole cam button surface is flat. (Dremel Hand Tool w/sanding disc)

 

[turbodave231]

I understand. No offense intended. I often see covers where this area is quite worn, grooved and uneven. Certainly bad enough that you wouldn't re-use them like that. I just machine them flat and compensate with more shims when using a roller cam.

 

[larrym]

Stock cam? a buddy of mine had an aftermarket cam the pocket on the cam snout was shallower than the stock cam it affected the spring tension.
This ended poorly for him the cam wore the face of the block.

 

[GNONYX]

I understand. No offense intended. I often see covers where this area is quite worn, grooved and uneven. Certainly bad enough that you wouldn't re-use them like that. I just machine them flat and compensate with more shims when using a roller cam.

Me personally, if I had a timing cover that bad, I would get one of Earl timing cover then to deal with shims.
Thanks again Dave, enjoy your weekend

 

[Nick Micale]

Stock cam? a buddy of mine had an aftermarket cam the pocket on the cam snout was shallower than the stock cam it affected the spring tension.
This ended poorly for him the cam wore the face of the block.

He probably should have made some provision to allow oil between the block and cam, as we have probably done over 100 of these roller springs and never have seen that issue?

 

[larrym]

Think it could have been cam bearing installation? The pocket was was quite abit shallower than the stock cam we compared it to I can't remember who made the cam.


Mobile larrym