Engine: Rocker Ratio

[CarCrosswordDan]

Did all V/8 Studes have an identical rocker arm ratio. Was it 1.0 to 1.5 ? Thanks, Dan

[whacker]

Yes, all of the V8 Studes had the same rocker arm ratio. It was advertised as 1:1.5, but it was really a little less, something like 1:1.406. I guess, by the rules of rounding, it is OK to call it 1:1.5. Stude rockers were the hot set up for Cadillac V8 racers for a long time, may still be for all I know.

[Mike Van Veghten]

Normally written as - 1.5 to 1

As noted, "approximately".
Which is very odd, because they are machined, not stamped. I've never actually checked any of them, but as machined parts, I'd think they should be closer to 1.49/1.51 to 1..!? Even that far back..!

Mike

[Bud]

I got a call from Joe Panek over at Roto Faze machine a couple of weeks ago about the Studebaker V8 rocker arm ratio. Joe is working on an old Cadillac engine and he is installing Studebaker rocker arms on it as the owner wants them in place of the original rockers for more lift. I guess the Cadillac guys are still using Studebaker parts in their engines. Bud

[CarCrosswordDan]

Bud, not sure but I'm guessing the Cadillac boys liked the adjustable possibilities of the Stude rockers rather than the ratio change. I don't think the ratio was different, but Caddy always used hydraulic lifters and Stude solids. So if you wanted a Caddy to run you got a solid cam ground and used Stude adjustable rockers. I don't know that for a fact and would like to get that thought confirmed by your Caddy buddy if you get a chance. Thanks, Dan

[Chicken Hawk]

Yes, all of the V8 Studes had the same rocker arm ratio. It was advertised as 1:1.5, but it was really a little less, something like 1:1.406. I guess, by the rules of rounding, it is OK to call it 1:1.5. Stude rockers were the hot set up for Cadillac V8 racers for a long time, may still be for all I know.

Most of the rockers I have checked were very close to the 1.5. I think the reason some claim they are not is not having the exact push rod length. Even the stock push rods can vary up to .040" or more and this will affect the ratio.

Also another interesting point, these rockers were built to take to stock spring pressure of around 135 pounds open pressure. When I put a roller cam in the '51 and springs that were over 600 pounds open I used the stock rockers wondering if they would break the first time I started the engine. I ran them for about three years and not one broke.

Ted

[Skybolt]

Ted,

Did you do any modifications to the rocker arms, like making them lighter, polishing them, shot peening them? Or where they stock standard?

[Chicken Hawk]

Ted,

Did you do any modifications to the rocker arms, like making them lighter, polishing them, shot peening them? Or where they stock standard?

No, nothing special. Jus took the 1/2" plugs out of the ends of the shafts, cleaned them out good, reground the rocker tips and put them back together and installed them. I would hate for anyone to do this and have one break but I have them on the Avanti engine as well with almost the exact same set up as the '51 had. Hoping I don't have one break on it.

Ted