stevesxm

anyone have a part number for a roller rocker kit that is a direct replacemet, no other mods nec , for the 502 mag mpi ?

JasonSmith

what year?

stevesxm

96 gen 6 mef3 injection. ser num 0l xxxx xxxx

Jerry B

I think all of the 502's had a non adjustable rocker from the factory. So if you want to install roller rockers you will have to replace the rocker studs. Easy to get these. Then any roller rocker should work. Just dont buy cheep ones.
Good luck,

Jerry.

JasonSmith

Jerry is right, you need some studs. ARP makes them, they are not that much $$. Jegs & Summit sell them, just order them with your rocker arms. The old ones screw out & the new ones screw in. The only thing I think you have to do is clearance some of the rockers. The Cranes that were on my old HP465 had a few corners ground off.

articfriends

iTrader: (1)

You will need the adapter rocker studs these guys are talking about,the stock stud holes are only 5/16 or 3/8 n/c threads but like mentioned arp makes studs and competition products in oshkosh wisconson markets a special stud for it too. Avoid the harland sharp roller rokers,there quaility has dissappeared,avoid the competition cam rockers,Tyler crockett has done spintron testing with them and claims they have nasty harmonics,avoid any no-name brand rocker as they are cheap chinese imports. Crane golds are the cheapest rocker I'd consider,especially for something you expect to run a few hours. You will have to grind out the oil dripper tabs in the valve cover and use a steel core rubber mark 4 style valve cover gasket between the cyl heads and o-ring in molded area of valve cover to have enough clearence for most roller rockers without buying new valve covers. You can buy new taller valve covers but you may have to re-mount stuff or make clearence for them and the pcv tubes/vents will have to be re-configfured,hope this helps,Smitty

TC

avoid the competition cam rockers,Tyler crockett has done spintron testing with them and claims they have nasty harmonics
Smitty, are you referring to the Comp Cams Pro Magnum rocker arms? If so please point me in the right direction so I can learn more about the test that Tyler Crockett conducted. I used these rockers on my new engine build and thought that I had made a good choice. Thanks! Tony

PPlay33

iTrader: (2)

I would recommend Crane as well. I have tried others, but pushrod length was incorrect for accurate geometry. Always check. Cranes seem to be close.

articfriends

iTrader: (1)

Those are the ones,I bought them for my current 540 also thinking they are a high quality steel which should be more durable then aluminum. First I had problems with the comp cams rocker nuts cracking from being too brittle until I changed them completely out for arp's,then when talking to Tyler in the beginning of august he says when he was doing Spintron testing with GM ( I assume during the 496 development that he was involved with) that they had awful harmonics and weren't stable.He WILL not run them on ANYTHING. I'm going to put Jesel shaft rockers on by spring if my budget allows or put my old Crane golds on with stud girdles. You could get more details from him if you want,810-324-2720,Smitty
My motor also gets a fair amount of condensation while idling,its never caused rust on any components but when I was wasting my time this summer with their nuts cracking they were starting to discolor and pit,I was under the impression they were stainless but I guess not.

TC

Thanks for the info Smitty! Will give Tyler a call before spring and see what he has to say about the rockers. I was sure I had chosen the perfect rocker arms. With claims of "lighter than aluminum, stronger than steel and rebuildable" I didn't think I could go wrong. I believe there is a stainless steel version of them that are available in both 1.7 and 1.8 ratios but they are considerably more expensive.