I recently swapped cams in my 383. I went much more agressive, and got some higher pressure valve springs. After the cam swap, it never did seem to run right. I've had to re-adjust the rockers 5 or 6 times, and the valve train get's noisy a few days after the adjustment. Anyway, I think the combination of the higher lift cam, greater spring pressure and 120k on the lifters has cause some to collapse. I've got 2 questions:

1: How do I determine if the lifters are faulty? I don't have a problem removing them, but how do you tell if they are indeed "collapsed"?

2: Will stock lifters be an adequate replacement with a .576 lift cam and stiff aftermarket springs?

 

I am not sure how you tell if they are collasped, but at 120,000 they should diffently be replaced. For the money you should go with the Comp Rs. (Combination Motorsports sells them for $207.00 compared to the $198.00 for Comp OEM replacments)

 

Definitely agree with this. You are only begging for trouble with your current set-up. I would not use stock replacements for that much lift and spring pressure.

 

Thanks guys!

 

If you go with the comp R's then make sure you do not overtighten them. Seth at combnation motorsports recommended that I only finger tighten them down, then start the motor and adjust them with the car running (one at a time). He also told me do not go more than 1/8 turn past zero lash if you go any at all. My car would not run with them set at less than 1/4 past zero lash.

 

Basically, when I rebuilt my motor at 60K miles I decided to use the stock lifters. It then went to the dyno to get tuned and I had issues with the rocker arms getting loose after WOT runs. I ended up collapsing 3 lifters. Like everyone said I would recommend going with Comp Cams R lifters.

 

Do you mean MORE than 1/4 turn past zero lash? You post doesn't make much sense if you mean you had to tighten them down more than 1/4 turn past zero lash when Seth told you less than 1/8.

 

I was told by everyone on this board to go 1/4 past zero lash. Sorry for the typo, I did not mean to mislead you. ricky

 

I'm still confused by that...did Seth recommend 1/8 or less? You went 1/4 (which exceeds that of course) based on recommendations from this board. Did you adjust them while running, or static?

 

Yes, Seth recommended an 1/8 turn or less. Nick from Nutek told me this when I emailed him "The R lifters are a near zero lash hydraulic. You basically adjust the play out of the pushrod, and give it no more than 1/16th turn pre-load, or no pre-load. It has about .010"-.015" plunger travel." So he recommended even less preload to me. The point I am trying to make is that everyone here tells you 1/4 turn and it should actually be less than that. If this is still unclear call or email Nick or Seth they will explain it to you.

 

Heres a good artical on lifter preload that might clear things up abit....it helped me.

http://www.gafba.com/content.php?article.7

 

Got it, thanks for clearing that up.

Does anyone know how to check a hydraulic lifter to see fi it's bad?

 

You did not make note of the pressure. What spring pressure are you referring to here?

 

I am really not sure of the spring pressure. They are a set of springs from combination motorsports. They will ahndle a .600 lift and are the stock diameter.