Engine and Transmission Tech

Timely thread comeback. I've been wondering what these adjustable rockers are from. They came with that unassembled high performance dry sumped Olds engine I picked up with the home made car I bought. I came to the conclusion that they were probably Volvo rockers, because that was the hot setup 20 years ago. About the time this engine was conceived.

Todd, are those rocker shafts actually fed from both ends? Bit over the top I'd say.

Jim

No, just one end. Other end is plugged with blue anodized AN type fitting. Also came with hollow push rods that I assume were designed to oil up to the adjustable tip in the rocker arms. My intent is to remove anything and everything that had to do with the dry sump and put it together as a nice stout Olds 3.5... with bigger valves, adjustable rockers, a big cam, new flat top pistons, ARP bolts, and every other neat part that came in boxes with this project. Putting this back to gather will be first on my list as soon as I finish the LS3/TR8 project.

Check the rocker ratio. Unless they have been modified they will be around 1.5

That'll cut into your base circle...

Jim

I seem to remember those Volvo rockers are 1.55. From the number on the cam box,I found some info and others here found some other info. Even with the 1.55, the cam that came with the engine should have somewhere in the vicinity of .500 lift. I'm not even sure they are Volvo rockers. Just an educated guess. Once the whole engine goes together, I'll take a little time to figure out exactly what all the pieces add up to. I can only hope, that the fella that went to all the trouble and expense of putting this thing together, had an idea what he was doing. After all, he was able to build this and its pretty cool.

Todd, Volvo rockers are steel and bushed to fit the smaller rocker shaft. Originally 1.5 ratio. They are offset drilled and tapped with larger 3/8" adjuster from 5/16" toward the shaft to get 1.55 ratio. Stock ratio is advertised as 1.6 but is actually closer to 1.55.

Those are the Volvo rockers for sure Todd. From the B-18 / 20 / 30 series engines.
And despite all the claims to the contrary they are all machined to pretty close tolerances.
Checked properly they will show a 1.55 to 1 ratio almost every time.
The issue with them is that the adjuster screw tilts away from the center line of the rocker. So the farther out that it is screwed the lower your rocker ratio gets. This leads to all the conflicting ratio reports.
But for an engine builder it's actually an advantage. Size your pushrods so that the adjuster is almost fully retracted and you come very near to a 1.6 to 1 ratio. Shorten the pushrods to extend the adjuster and you can get to 1.48 to 1.
As Jim said, having a machine shop offset drill the adjuster holes to accept a 3/8 adjuster screw gives you all the latitude in rocker ratio that you could ever want.

Live like you mean it.
Fred



Edited 1 time(s). Last edit at 05/18/2016 08:06PM by DiDueColpi.

Todd, "looks" like your application is using the Olds shafts,(smaller than Volvo). I would worry about the Olds shaft for cracking/breaking, in your application, as they are even weaker than the Buick shafts, because of the 7/16 " head bolt through them. Good Luck, roverman.

Sorry Art, but those are the Volvo rocker shafts. Should be good to go!
Are those pedestal bolts just temporary Todd? As they look far to short to be the Olds headbolts.

Fred

The Olds engine came with three boxes of ARP bolts. Head, main, and rod bolts. If anybody want this Olds engine I'd be happy to let the whole thing go for $1000. Let someone else figure it out. I'll even throw in a spare olds engine that is in pieces and greasy. The new individual parts would cost more than that. Had a guy with a 63 Olds come look at it and he passed because the mods were too much for him to comprehend. I guess MGB V8 guys and 63 Olds guys aren't cut from the same cloth.

I've got a 62 Olds and I'm definitely interested at that price. Where are you located? You can contact me directly at joe_padavano@rocketmail.com

Todd, Will you be allowed to run a non-vintage motor ?

Not a race car. Looks like a race car, but the builder intended it to be a one off street car with a custom body. Not sure what I will ultimately do with it. Proportions are all wrong and can't be seen thru the photos. If I end up doing something with it, I'll probably remove the entire aluminum center section and connect the front and rear with steel tubing. Keep the body work very minimal and run it naked. Sort of like a homebuilt locost. For now, its just a bunch of cool stuff that doesn't work all that well together.... but I can fix that.