I just got the car back together after having the heads milled .012" and installing a set of Crane lifters. (which I think are the same as the Comp R's) I've also got the T1 cam from MTI. When I first started it up everything sounded fine. Noisy as hell since the springs were kinda dry. I ran it for about 2 minutes and shut it off to change the oil. When I fired it back up there was a loud knock coming from what sounded like #1 cylinder. My guess is that once the new lifters started to pump up it is starting to push the valves far enough to where it's starting to nip the piston. I pulled all the rockers and checked the pushrods and noticed that when I was torquing the rockers back down it was pushing the valve open slightly on all the cylinders. Any ideas?

 

The pistons are not hitting the valves with a T1 if it was installed correctly. You never stated what length PRs you are using. If they are 7.400 you should be ok. .012" is not much off the heads. You could have a lifter problem though. They do take a little time to get filled with oil, so run it a little while longer. I've heard of bad Comp "R" lifters right out of the box.

Brad

 

Thanks. I've had the T1 for a long time now so it's not that. I'm also using the stock pushrods. I'm going to run a compression test to make sure all the valves are seating right. I'm also going to try spinning the motor manually to see if I hear anything.

 

Yes your pushrods can be too long! I had the same thing happen about a year ago on a customers car. Comp cams ground the wrong size base circle on the cam and wa la 3 bent valves from incorrect pushrod length with the abnormal base circle