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Author Topic:   Clearancing roller rockers for 1.550 springs
BrianW
Dirt Freak

Total posts: 385
posted May 02, 2005 10:02 AM  
OK - I've got some of the stainless steel rockers (comp cams pro-magnum or a knock-off - came with another engine) and the 'support ribs' on the underside of the fulcrum to the arm ever so slightly hit the retainer and spring on the large roller cam springs.

Can these be clearanced or should I use a set of older aluminum rockers that I've got which are already 'factory' clearanced for the larger springs? Will clearancing them (about .040-.050 or so from what I can tell) weaken them or is it necesary and I shouldn't worry about it too much.

rocket36
Dirt Freak

Total posts: 209
posted May 02, 2005 02:08 PM  
you definitely don't want the retainer to be able to come in contact with the rocker arm or you may have a major failure. most likely a dropped valve which can then lead to some real serious damage.
clearancing rocker arms is quite common but not really ideal.
i would trial some longer pushrods to see if that gives enough clearance.

BrianW
Dirt Freak

Total posts: 385
posted May 02, 2005 02:58 PM  
The longer pushrods might work, but the geometry looked wacked - the roller tip was on the edge of the valve and I'm worried about wearing out the valveguides that way.

mdsteacher
Dirt Maniac

Total posts: 145
posted May 02, 2005 03:36 PM  
We had the same problem but our springs are 1.60" for roller cam. We had the comp. cams pro magnums and they were hitting the spring. These were machined to clear spring but to no avail. Comp. cams actually recommended the stainless steel pro magnums (part number 1104) to solve the problem. They said they are good to 1.65" spring. Just got them today and way expensive. I would suspect your rockers might be knock-offs or not the stainless steel ones.

sdhnc29
Dirt Forum Champ
Total posts: 934
posted May 02, 2005 04:10 PM  
When we have to use pedestal style rocker's, per rules that do not allow shaft rocker's, we use the Crower stainless rocker with the back-set trunion. These are designed just for the spring diameter's that your running. I suspect that the Comp rocker's mdsteacher just bought are probably a copy of the Crower. These rocker's are built on a big block Chevy body, and the trunion is offset to the front in order to move the body of the rocker back away from the valve spring.

Steve

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Rutherfordton , NC
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David Blue 22
Dirt Roller

Total posts: 6
posted May 02, 2005 05:41 PM  

I just went through setting mine up with 1.550 springs. With a taller install height longer than stock pushrods are probably needed. I am using Scorpion rockers and the clearance is about .040. I also have a set of Harland Sharp high ratio rockers and they had more clearance.
Try using lash caps with the longer pushrod.

allan
Dirt Maniac

Total posts: 107
posted May 02, 2005 11:24 PM  
had that problem with some aluminum rockers and just used a die grinder to clearance them.

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