Rocker Stand Shims
Rocker Stand Shims
(OP)
Hello, I am have been lurking the forum for a while and finally decided to join. I am looking to fabricate shims for rocker stands for the rocker shaft assembly on a 1957 Olds 371. I am looking for a material that will be readily available and somewhat easy to machine. I was leaning towards a copper or copper alloy, but wanted to get some other opinions. Any recommendations would be greatly appreciated. Thanks in advance!
Chris
Chris





RE: Rocker Stand Shims
Regards
Pat
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RE: Rocker Stand Shims
The way the stands are set up I can only use washers on three of the six stands; the others are a complex shape (one shim also needs an oil feed hole).
RE: Rocker Stand Shims
The oil hole might be problematic. Is there some way you can drill the hole in a washer and stake it in place. Maybe drill the oil hole to accept a suitably sizes metal tube in the head and the washer and use it as a hollow dowel to locate the washer.
Regards
Pat
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RE: Rocker Stand Shims
RE: Rocker Stand Shims
I added a McGurk solid lifter cam and high lift rocker arms which necessitated shimming the rocker stands/changing pushrods. I simply used some steel shims cut to fit each stand...That sounds too simple, looking back...but...other than it was a real pita dropping the pan just to change cams, that's what worked in 1961.
Rod
RE: Rocker Stand Shims
That being said, I actually had a chance to buy some used adjustable rockers and McGurk rings a bell, but I think they were Thomas(?). I do remember that they were magnesium and I heard that they were prone to breaking, and the looked a little rough around the edges for the price.
I had some custom rockers made from Harland Sharp a few months ago and I do need to correct the geometry. I put some precision ground washers under the rocker stands last weekend to get an idea of how much shim I need and I am looking at ~0.100" to get the roller tip on the center of the valve. So, maybe I'll just order up some precision stock and get cutting. I do have access to an old school Bridgeport mill, but I am not very good at it...lol. Perhaps this will be a chance to learn.
Thanks,
Chris
RE: Rocker Stand Shims
The McGurk rockers were higher lift ratio than stock and adjustable for the solid lifters. Not roller rockers. The shims were thin enough to cut by hand, no mill, no lathe, no nuthin' ! Put two wheels on the curb so I could gain access to drop the pan, etc, etc. Most parts came from Juarez, Mexico scrap yard except the chrome interior stuff. Upholstery was U.S. Navy surplus wool blankets.
Engine was as stated with a 49 Olds hydromatic and a 48 olds rear converted to coil springs and with a 4.10:1 ring and pinion. 8.20-15 Atlas Bucron Coushinairs for bite. Ran in the low 13's at about 100 mph...fair, but not a winner. I spent too much on the chrome stuff and ran out of money/interest when the 40 came along (and, of course, the little 16 year old red head---all the cars are just a memory, but I still have her.)!!!!!!!!!!!!
Rod