Cam Timing and cam tensioners
 

I am putting my engine back together. I have timed the cams using the factory tools. What puzzles me is this. As I turn the engine over with all the rockers in place the chain tensioner "collapses" 3 times on each side during a full firing cycle of 720 degrees of crankshaft rotation. This happens with the tensioner tool in place, as well as with the normal tensioners in place. I realize that if the engine were running the tensioners would "pump up" due to oil pressure. I did use racing springs that have a higher spring rate. Could this be causing this? Has anyone seen something like this before?

Pete

Pete, I would have suggested the tensioners are opposite "ober" and "under" ,but you have mentioned you had the tensioner tool in also. Check them anyways since one is longer than the other.

The tensioners are in correct. As a test I removed all the rockers on one side, and the problem went away on that side. I think that the "stiffness" of the valve springs is trying to stop the cam at the point of maximum lift, which is why the tensioner collapses. I don't know if the hydraulic valve lifters play any role in this. I called Bob at anchor atlantic (he did the heads) because I was concerned that maybe the valve springs were going into coil bind. He doesn't think that is the problem. I tried to check this. With a valve at max lift I could easily get a feeler guage between the coils of the outer spring so I know that isn't the problem. I really can't figure out how to check the inner spring.

Pete

Pete, one thing I learned is you need to replace the hydraulic lifters when you put in new heavy race springs. Check all the lifters and make sure they are in good shape top and bottom or just suck it up and change them at 36 bucks a pop.