cams and rockers

75-911S · 02-13-2005, 02:25 PM

After reading the thread on replacing/matching cams and rocker arms, I have a question about using old cams (in good condition) with new or reconditioned rocker arms. From what was discussed and what is said in Wayne's book, it's clear that you should use new parts with new parts and old parts with old parts (old rockers on same old cam lobe). But what if you have a couple bad (pitted) rocker arms and you want to replace them - or what if you have all the rocker arms reconditioned? Can you use the old cams? It appeared that this might be okay with a 20 minute engine break-in run at 2000 rpm to "mate the surfaces." Right? Wrong?

Eagledriver · 02-13-2005, 07:38 PM

I feel your pain on having to make these decisions. The safest thing would be to have the cams reconditioned. That having been said I think you can get away with what you have planned. I put a reconditioned cam into one of my cars without reconditioning the rockers and it seemed to be fine. I had the car for 3 years and 15k miles after that and the wear patterns look ok. I also rebuilt my race motor last winter and put different cams in without reconditioning anything. I used some steel wool on the cams to rough up the surface to take off the hardened layer. There is some slight scoring on some of the lobs but I'm happy with how it looks so far. The engine has 6 race weekends and 3000 miles on it now.

If this is a steet engine that you want to get another 100k miles out of then I'd get the cams reconditioned.

snowman · 02-13-2005, 10:19 PM

Yes, you can use reconditioned rockers on an old cam, no problem. Just use a good cam lube, eg a moly grease for break in.

camgrinder · 02-13-2005, 10:56 PM

The biggest problem you can have is side loading the edge of the rocker arm pad and the cam lobe. If you really have to use old parts, take some prussion blue and coat the rocker pad. Assemble the cam and rocker arms into the camshaft carrier. Then turn the camshaft over and wipe the blueing from the rocker. This will leave a pattern on the rocker pad. If the contact area (wiped clean portion) is at least 80% It should work.
If the rocker arms are pitted, the cam lobe will also be worn. The wear on the lobe may not be as easily seen as the pitting on the rocker arms.

75-911S · 02-14-2005, 03:51 AM

Thanks for the quick replies guys. I'm trying to put a good street engine together that will give me at least 50,000 miles. So I want to do this right. But I also don't want to spend money needlessly. Since my cams look so good I thought I'd just go the rocker reconditioning route which a previous thread indicated could be done for less than $250. Any idea what it would cost to recondition the cams too? And where is a good place to get them both done?

ChrisBennet · ChrisBennet's Garage

Jetkona wrote in this thread

Quote:

Rocker Arm Specialists 800-747-2767 Gary or Blaine. $9.50 each for re-radius & new bushings. Turn around is 2 - 3 days.

I have a friend who sent some out to this place the other day but I haven't dealt with them directly or looked at their work yet.
-Chris

snowman · 02-14-2005, 03:19 PM

Call Dema Elgin http://www.elgincams.com/
All you ever want or need to know about anything to do with cams and one of the best places for regrinds.

DonE · 02-14-2005, 04:40 PM

Quote:

Originally posted by camgrinder
If you really have to use old parts, take some prussion blue and coat the rocker pad. Assemble the cam and rocker arms into the camshaft carrier. Then turn the camshaft over and wipe the blueing from the rocker. This will leave a pattern on the rocker pad. If the contact area (wiped clean portion) is at least 80% It should work.

Yow, great advice - thank you