[61 vent]

Hello all, during the clean-up phase of the new to me 56 317, I removed the drivers, LH valve cover, and discovered the 2 rocker arms had been touching the cover. I looked closer and found out 2 things. 1 all the press in studs have roll pins retaining them, and some are backing out it appears. 2 the 2 rockers that had been touching appear to have newer pushrods than all the rest. Has anyone else come across the roll pins retaining the studs? is this common, or standard practice? Thanks

[Bill Hanlon]

Pinning press-in studs was a popular "fix" for early Chevy V8 engines. You can still buy kits to do this from people like Summit. Given Pontiac's through the stud oiling I'd think it would be less popular with Pontiacs.

[61 vent]

Thanks, Bill, I noticed a few of the pins look to be backing out, and one rocker arm has a thick washer under the rocker arm nut. I would post a few pictures, but not the easiest.

[Bill Hanlon]

I'm guessing that the rocker arm with the washer has pulled partially out of the hole. Laying a straight edge across the top of all the studs should show you which ones have pulled out part of the way.

The proper fix according to the shop manual is to remove the loose studs, ream the hole to an oversize (the book doesn't say what size ream), but the oversize studs are GM part # 520165 and are listed as .003" oversize. Probably made of unobtainium. The GMC maintenance Manual (GMC V8s in the 50s were Pontiac V8s) procedure starts on this page http://chevy.oldcarmanualproject.com...5559mm413.html
and continues on the next. There are also special tools to remove and install the studs.

Screw-in studs are possible, but I've never seen them with oil holes. Two solutions to the oiling problems would be:
1. find a machine shop that would drill the screw-in studs to match the press-in studs.
2. replace the rocker arms with parts having a hole in the pushrod socket.

But first, wait for Jack Gifford or some other early Pontiac V8 expert to weigh in.

[Jack Gifford]

I doubt I can be of much help. But I do know that pinning of stock studs was quite common with early Pontiac V8s. The pins were hardened dowel pins, not roll pins. The drillings for the pins only went about 1/8" into the studs, so the oil passages were still functional. Clearing all the chips away was worrisome if the heads weren't removed to do the pinning.
As for oil holes at the pushrod ends of early rockers- back in the day I gave up on it- hardened too much to allow drilling. These days I suppose a person could EDM holes in them. [note: I DO have an EDM mill if someone wants to try that route]

[55Wagon]

Thanks for all your valuable insight, I will be in the garage today and will check some items mentioned

[55Wagon]

Puller passenger R/H valve cover, and all normal. Placed straight edge and all the same. I guess I will loosen the rockers and measure pushrod lengths.

[55Wagon]

pulled a few old and newish push rods and all are the same length, 2 different designs but the same length. I am going to put it all back together after I adjust the rockers per the 55 shop manual. Thanks

[Bill Hanlon]

Are you planning to push the studs on the L/H head back to "normal" height? Are there any that are too high and have not been pinned? Do you plan to re-pin those that had pins?

Stud R&R routine can be found here, starting on page 6-12. https://www.pontiacsafari.com/55/Sho...Mechanical.pdf

Rocker nut adjustment can be found in the same book, starting on page 46, paragraph 24.

[b-man]

Isky Cams used to carry some screw-in studs to convert early Pontiac heads.

You could always call them to see if they still have something that will be compatible with your heads. I had one version of those studs at one time (never used them, I sold them) and they were drilled for oiling through the studs.

[55Wagon]

Bill I laid a straight edge across the rocker arm studs, and all are exactly the same height. so no idea as to why or when the contact on the valve cover occurred. I will rotate the engine and make sure the valves are closed, and adjust per the shop manual.