Comp Adj Cam button

[buickboy]

Installing cam today and when i was setting the cam end play I was short
.0025 of cam button shims. is this normal and where do you get the correct button shims?

Mitch

 

[forcefed3.8's]

How much clearance do you have now? Is your front cover worn? What front cover gasket are you using? The Felpro is thick. The GM is the best to use, but I think is discontinued. I think the Cometic is thinner??

 

[buickboy]

New front cover, using felpro gasket. Used all shims that came with the CC button and still need .0025 shims. Sound unusual? Where to get more shims?
Installation instructions for this cam button?

Mitch

 

[counterman]

Mitch, are you using an aftermarket cover or GM piece? I just went through this with a Comp roller. Firstly, the cam had too thick of a thrust area by .040. I had that machined down in order to prevent the lifters from hitting adjacent lobes on the cam. It seems that the Comp lobes are wider than a flat tappet piece, and the room for variance is small. In any case, I was attempting to use a Pioneer 500231 cover on the install. I had a stack of shims, and needed more, like you, to get to a reasonable end play. I used hardened washer stock from the hardware store, and mixed and matched until I got the right clearance. Then, much to my amazement, I found, like many others before me, that the cam sensor hole was bored off center and I could not install the sensor in the Pioneer cover. I switched back to my old GM cover, and I had WAY too much length with the shim pack used on the Pioneer unit. I redid the whole deal again, and was right in spec with a few changes to the original button stack up. Fel Pro gaskets both times. Conclusion: the original GM cover is closer to spec with even noticeable wear than the China covers can hope to be. Add that to a long list of problems with the import covers out there now. Good luck. Rudy.

 

[buickboy]

Rudy-

I am using a new Hi Vol cover from full throttle. Cam sensor fits perfect and the cover is flat. What amazes me is that you and i are the only ones out of thousands of Comp cam kits sold that are having shimming issues. Got to be something I am missing besides more shims.

Mitch

 

[turbo nasty]

Have you guys contacted the vendor purchased from or comp cams about this??

 

[counterman]

Mitch, I do not know who makes that cover, but it may just be that the cover is made a little different in the area that the button rides versus the oem piece. Like I stated, I know that the GM cover required WAY less shimming than the Pioneer unit. However, I was able to get a usable end play with the different washers I substituted with the Pioneer unit, it just took some extra work. I was really bummed with the Pioneer unit, however, as it was very well done in terms of oil pump cavity, flatness, no flashing in the passages, and even overall appearance. They just offset the cam sensor hole by maybe .050-.060, causing a no go with the sensor. I kept it, because it might well be all that is available down the road, and I could have remachined the hole to get clearance, but I am not comfortable with the fit to the cam gear with an oval hole locating the sensor, or a possible different angle with the China cover. The cam was a real head scratcher. It spec'd out like my flat tappet Edelbrock except that the thrust surface was visibly thicker than the old cam, forcing the cam forward by .040. This caused the lifters on several cylinders to rub the lobes adjacent to them. My measurments from the nose of the cam to the back of the large flat area on the front of the cam were the same cam to cam, but from the nose to the back of the thrust surface was longer by exactly .040! I had my shop recut the cam thrust .040, and, bingo!, no more problem. The shimming problems were after the cam was recut, so it is apples to apples. Before cutting the cam and with the GM cover, I could not remove enough shims to get the proper endplay, and went so far as to thin out one of the shims to get a good number. Then, I noticed that the lifters were stacked on top of the lobes next to them! Bison said in an earlier post that he often finds questionable issues on these engines unless they are bone stock. I suppose that is why everything has to be checked and rechecked on the build. I imagine that plenty of the engine failures occurring are caused by these type of issues not being caught before installing. Good luck. Rudy.