Stock Stude Rocker Arms and pushrod lenghts

[oldvinyl]

In simple laymans terms please explain the changeover in these two variations, Why??? Tom.

[Alan]

Please simplify your question.

[whacker]

I think oldvinyl wants to know why the early and late pushrods are different lengths. I think the change over occurred in 1955 with the new bore size. I understand the question, but I don't know the answer. I do know you can use the earlier ones in the later blocks, and the later ones in the ealier block, but only if they are all the same and matched to the rockers. You can't mix them.

[Alan]

As far as I know Stude used 1 pushrod from 51-64 ball on both ends no oil hole and 11.265" length. They changed the lifter diam. amd material in early 53 but other than that I kmow of no change in rockers or pushrods. If anyone has any that are different I would like to know.

[whacker]

Well, a seach of google turns up this, quoted from a post by D. LeVesque (an old pro!) concerning the push rods. It appears the change is about 1962 or so:

The pre 1962 engines USUALLY have the shorter pushrods, but you can't
be sure that it is still the same if someone has worked on it in the
past.. A common swap long ago was to put later rockers with the built-in
oil retrictors in early engines to slow down the oil consumption.


Maybe if you ask David, he can shed some light on this for us. I'va always found him to be quite helpful if you approach him with a question.

[whacker]

Here is a quoted message from Ted Harbit about the same time, maybe even the same thread:

TedHarbit Jan 1 2001, 11:43 pm show options

Newsgroups: alt.autos.studebaker
From: tedhar...@aol.com (TedHarbit) - Find messages by this author
Date: 02 Jan 2001 04:42:35 GMT
Local: Mon, Jan 1 2001 11:42 pm
Subject: Re: Rockers
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>Do I understand that the rocker arms are interchangeable (54-61' / 62-64'),
>except for changing adjusting screw ??>


Yes, they will interchange but you might not have enough adjustment on your
screw in the late rocker on the early shaft and push rod. If you turn the
adjusting screw too far down to get proper valve lash, the screw may not have
enough torque left in too few threads to keep from loosening up. The cure would
be to use the late model longer push rod.

Shortly after the '61 models came out,they changed from the shorter push rod to
the longer one and the longer adjusting screw to the shorter one. The
difference in the push rod was about 5/32" and the adjusting screw about 1/8".


The only possible reason I know for the changing was that the late model V8
used the same rockers and adjusting screws as the overhead six did then.??


Ted


I still don't know why the change, but there does seem to be some change in 1961 to 1964.