The Stovebolt Site Forums The Shop Area Engine Shop Bumps on I.D. of rocker arms?

I've got a spare rocker assembly off of a mid 1954 head that I'm reconditioning.

I got a set of the reproduction rocker shafts on Ebay because the original shafts had deep grooves worn in the bottoms where they contact the rocker arms.

I used a benchtop disc sander to take the grooves out of the rocker tips where they contact the valve tips.

When I go to put the rockers on the new shafts, I could feel resistance near the center of the rockers travel.

I looked at the inside diameter of each rocker arm where it rides on the shaft and there is a round button of metal in the bottom I.D. of each rocker arm corresponding to the oiling hole in the bottom of the shaft. The button has a groove it in that matches the oiling groove around the rest of the rocker I.D.

My theory is that the metal that wore off of the shaft settled in a depression that may have been machined into the bottom I.D. of the rocker arm. The groove would have been kept open due to the ridge in the shaft where the metal didn't wear away.

Has anyone else ever seen anything like this? The button of metal was resistant to a pick that I used to try to pop it out.

Rob

Those shafts are definitely junk, and so are the rockers- - - -especially after mutilating them with a belt sander. It might pe possible to ream out the rocker bores and press bronze bushings into them, but the radius of the tips are critical and need to be the same for all the rocker arms. There's a fixture for most valve grinding machines that is able to resurface rocker tips correctly- - - -or at least make all of them match. It looks like you need to go shopping for a complete rocker and shaft assembly- - - -they show up on Ebay pretty frequently. Once you come up with a complete replacement assembly, you're going to need to address the source of the lack of oil flow that caused the original shafts and rockers to wear out- - - -that assembly has run dry for thousands of miles to do that much damage.
Jerry

That rocker set is in really bad shape. With that much wear, I am with HRL that you are not going to be able to rebuild them in any proper sense. As for reconditioning, the outfits that rebuild these things generally machine down the shafts to get them even, then they are re-plated and build up with hard chrome. The rockers are all bored/honed out to a standard size, and the shafts are then machined again but to the appropriate size for the now resized rockers. Tips are reground in a fixture, adjuster balls replaced.

I have seen bushings used, press them in, drill the spit hole, machine the inside grove.

if you find a decent replacement set, save your pennies and have them professionally rebuilt. Rocker Arms Unlimited in California is one of the very few places that I know that does that kind of work. Not cheap but they can do what you cant with those rockers.

And yes, like HRL noted, before you install them, you need to fix the oiling issue, which is not an unusual issue for motors that have been around the block once or twice.

Yeah, those parts are trash bin candidates. That button on the bore of the rockers is the original metal that didn't wear away because there was no contact with the shaft. The oil hole was there and air or oil doesn't wear metal, metal to metal does.

There’s usually a seller on eBay with the rocker shafts for 100-ish bucks.

The rocker arms themselves would be a little tougher to piece together….if you wanted ones in good shape.

Dragsix- will that place in Cali add metal to the rocker tips before re-grinding?

There should be plenty of material on the tip to allow for substantial regrinding without adding any metal. The clearance at the rocker tip is approximately 1 1/2 times the movement of the adjusting screw on the pushrod side- - - -no problem with removing a few thousandths at the tip to reshape the contact patch. Running bronze bushings instead of steel on steel should dramatically reduce the wear involved. The Chevy engineers never intended these engines to run for 70+ years- - - -maybe 10-15 at the outside?
Jerry