Technical Early Oldsmobile Rocker Shaft Differences

Good evening fellas, I'm in the rebuild phase of an early Oldsmobile 303...it will be outfitted with a pair of 324 heads with Isky adjustable rockers and here lies the question....

While tearing down the rocker ***embly I noticed one of the shafts is slightly grooved from wear. So I sourced an NOS shaft which came in the original GM packing etc...however the slots and diameter of holes are smaller than the stock shafts that are on the motor and than those the adj rockers were on.

The diameter and length of the NOS shaft matches the others which came off the motor and match the shafts the Isky rockers were on....

Due to the nature of the sensitive top end oiling system of these motors, I'd like to make sure either the NOS is an acceptable replacement or if I should hunt for replacements to match the worn pair.

Has anyone else come across the different relieves patterns before....diagonal vs straight?

....Thoughts?

 

I've seen at least three different variations of rocker shaft oiling holes and grooves on 303/324 shafts. No doubt that the O.E.M. shafts had a design change or two, and then there were several aftermarket companies that made them.

 

You could always drill out the holes to match the used ones.

 

That's the plan...wanted to see if the angled slotted shaft was for 57-62 and if so if that matters...

 

'57 shafts were longer.

 

I can't answer your question but I like the slanted slots, allows a wider oil "trough" for the width of the rockers to ride on.

Aftermarket Mopar rocker shafts have the wide slot that runs the width of the rockers, they say they're really effective on the cast adjustable rockers. Infact I have a set showing up this week.

..

 

the oil holes are good,
the hole for the locating pin should be drilled to just let the pin be driven in with a minimal interference fit.
or a stepped pin used.
if drilled you should pull the plugs from the ends and clean any chips out.
all shafts shown look like they are for 1.5:1 rockers

like heathen said the '57 shafts are longer
and all shafts for the 1.8:1 ratio rockers have grooves to allow head bolt clearance

 

Lostone, I feel the same, the diagonal full width seems like it would oil better...

 

Paul, thanks for the information, exactly what I was looking for. There are grooves on the shaft as well, now that you pointed them out. Can 1.5 rockers work mounted to 1.8 shafts? I would ***ume it's possible if the holes are all in the same location....

 

ah yes, I see them now on my computer, missed them on my phone.
of course the 1.5 rockers must go with 1.5 towers
and 1.8 rockers go with 1.8 towers and shafts

 

For extra oiling many of us run chevy lifters with custom length rods using hollow push rods at the end of the heads, front and back and solids everywhere else. Learned that from Tony at Ross Racing who builds a lot of early Olds engines.

 

Thanks for the tip VT...I'm planning on doing that very trick...now time to ***emble the rocker shafts, thanks again everyone.

 

That NOS shaft (the bottom one in your pics) looks much like the Olds 215 shafts I have on hand. Not sure if they were shared with other Olds V8s or not, but...:







I did see Kanter has Buick 215 (might've been 300-- very similar, either way) listed on eBay, so might be worth asking them if they have what you need.

 

nope, not the same

 

I got new shafts of eBay, Falcon Enterprises or something like that. Not cheap but nothing for old engines is. I haven’t used them yet, I need a good set of 1.8 rocker stands.