<VV> Cam Defects - (was: Cam experience poll)

[Dale Dewald]

At 17:39 3/09/2011 -0500, Carlton Smith wrote:

>Bryan, In my instance, yes indeed the valve geometry was checked and
>corrected. It did take longer pushrods. The engine was reassembled with the
>Clark's 260 cam and there was no difference in the clicking valves. It was
>definitely the cam causing the problem. We cannot point a finger at the
>Clark's Sealed power lifters too though. As I said before we tried sticking
>a Source lifter that we all know was good in one of the clicking valves and
>there was absolutely no difference. Cracked the engine , installed new Isky
>260 cam and Source lifters and all was quite right at the start up.

The previous owner of our '65 Greenbrier and I both had this 
problem.  Numerous replacement lifters, pushrod, rockers, etc and even 
replacing the head had no effect.  In this case, upon tear-down of the 
engine by Ken Hand, it was found to have an aftermarket replacement 891 
style cam (unknown manufacturer) from a previous rebuild.  It turned out 
that the base circle of one cam lobe was slightly out-of-round, therefore 
not providing the lifter a constant position to fully pump up during the 
closed part of the valve cycle.

>With what Jim Allen is writing as he has used many of the Clark's 260 cams
>with only one instance of trouble, this whole scenario may be a fluke in
>manufacturing on occasion.

I would have to agree. Ken Hand told me he has seen this on a number of 
occasions with various brands of cams.

>I should have mentioned earlier that the clicking valve would adjust out
>quite and come back clicking again in 3-5- seconds.

This is exactly the symptom I noticed.

Dale Dewald
Hancock, MI