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 Rocker arm adjustment different issue

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cfd2dc21 Posted - 28 Dec 2017 : 08:37:58 AM
Hello all. I have been a Pontiac guy for many years now and have followed this site, but this is my first post.

I need some help with an issue I have on a 455. I am trying to adjust the rocker arms. I have read all the threads I could find on the site and Bill's how to article. What I have is different than I have been able to find. I'll try to describe it as best as I can.

Rebuilt 1973 455 with 6x-4 heads. Heads were surfaced once when I did the rebuild. (they came off an original engine) Summit 2802 cam with comp 995 springs and comp cams Magnum roller tipped 1.5 rockers. Std length pushrods. I had the original 7/16 / 3/8 studs with the comp lock nuts. I adjusted the rockers like the article says with that set up. After the preload was set, it seemed the nuts did not go on far enough to ensure a good hold. (there was one thread showing above the nut) So I saw Bill's article and bought the 134-7103 studs and installed them. I am using comp 7/16" lock nuts.

So here is the anomaly. I did the tightening just as the article says. Rotate the engine etc...I tighten the nut down until I feel resistance on the pushrod. I go to do the 1/2 turn to pre-load and at 1/4 it tightens down tight. After a bit, you can jiggle (technical term) the rocker arms side to side.

Just doesn't seem right and I don't want to wipe out the cam. Any thoughts or help would be greatly appreciated.

Jeff

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loosetappet Posted - 11 Jan 2018 : 6:10:37 PM
Many stud choices, hard to choose. If this helps anyone, all the better. For my 400, roller rockers, mild cam, and stock valve covers I used the ARP 135-7101 and short polys. Adjuster thread length .850. With the 1/4 inch felpro gasket I had no clearance issues.
Blued and Painted Posted - 28 Dec 2017 : 11:09:16 AM
Make sure the set screw in middle of rocker nut is backed out far enough.
Is there enough threads cut in the studs for full range adjustment.
With no push rod, does the rocker trunnion slide easily down on the stud.
Is the valve hitting the piston.

Page 1, Post 31 in Light Reading Non Fiction there is a good video about rocker geometry.

I have not figured out cut and past on the kids I pad yet
cfd2dc21 Posted - 28 Dec 2017 : 11:05:01 AM
UPDATE:
I found a reply to a post from someone on here and may have fixed the issue. I just purchased ARP 100-7101 studs. The new studs have a thread length of 1.0" compared to the 134-7103 at .670". This SHOULD give me the adjustment I need. I will let you know.

Jeff

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