SBC Rocker Arm Problem

I just finished the 327 in my roadster and was setting the valves and noticed the rocker on the #3 intake is wanting to rotate sideways. The rockers, pivot balls, nuts, and pushrods are new. It rotates almost off the valve until the push rod hits the slot in the head. I swapped the rocker and related parts with another valve and the same thing happens on the #3 intake so it is not the rocker. What could cause this?

 

Sounds like the pushrod hole slot is too wide. You'll need to use a guide plate. Hope you have screw-in rocker studs!

 

Check the stud on that rocker for wear. I have seen them worn on the sides where the rocker arm contacts them because at an earlier time the ball/rocker arm were worn out. Dennis D

 

Slightly bent stud???

 

I had one do that one time and it end up being the heads were angle milled to raise compression and the push rod was rubbing at the bottom of the hole and causing it to bow.

 

I had a set of 461 heads that someone had installed screw in studs and guide plates and had drilled and tapped one at a slight angle. The rocker on that cylinder needed adjustment constantly and would eventually saw into the stud. The cheap fix was I installed a roller rocker on that cylinder, and it worked ok even though it wasn't perfectly straight.

 

Bent stud is my guess. Guide plates might help....I'd keep an eye on it and watch for wear.

 

probably a bent stud but check for any other signs of pushrod contact with the head and make sure pushrod is straight also. If you need a guideplate you can use Mr Gasket part number 1160. These guideplates mount using the head bolts, but they require a little clearance grinding to eiher the head stud boss or the plate itself. I have used these for years in special circumstances like yours and they work great. Good luck!

 

If stud and pushrod is ok then hole is probably too wide. You can use a stock vortec self aligning rocker arm. Also come in roller versions also. depending on if using stock or roller rockers. I believe to put a guideplate on you would need to machine the boss the stud goes in and then tap the hole for a screw in stud. Unless you use Bluice68 suggestion. Have to do the exhaust also because guideplate work in pairs on SBC. Make sure the valve stem above the keeper is longer than the self align protusions on the vortec rocker. I done this before because pushrod holes had been hogged out on some old heads. This is usually less expensive fix. just need one used vortec rocker arm. Most folks have plenty laying around. I got a couple of dozen. If ya need one I can give you one.