Gary M

Using a Camera from Summit Racing, I filmed down the distributor hole.
Is there a washer missing here?
does it look like the distributor gear has been rubbing this area( judging by the picture of the gear)? It may be damage from a past distributor. Thanks in advance for any thoughts. This is down in the block and the oil pump rod goes through it. I read somewhere there is a washer that holds in the oil pump rod. It this that washer or is it missing, also it looks heavily worn?
The distributor that I took out. Oil pump rod came out too.
This is a picture of that flat area down in another block I have for comparison. It does not look near as bad as the block in the car.

TripDeuces

If you look closely on your oil pump drive shaft you can see that line that runs the length of the shaft. It's actually a scratch where the retaining washer was dragged down the length of it. It's now in the bottom of your oil pan.
Don't worry about it it won't go anywhere.

joe_padavano

The "washer" is actually a small pressed-on retainer that goes on the oil pump driveshaft on the underside of that boss. The sole purpose of that retainer is to keep the oil pump drive shaft from falling out of the block when the engine is upside down having the oil pan put on before the distributor is installed. It serves no other purpose. Your oil pump driveshaft is now wedged in the distributor gear (not uncommon) and as Trip pointed out, the retainer got pulled off the shaft on the way out of the block.

oldcutlass

There are shims you can use to raise the distributor body a few thousands if the gear is actually rubbing on the block.
https://www.summitracing.com/search/...utor-Shim-Kits

Gary M

Thanks. Big relief, think I'll get the shims just in case.

For or anyone wondering how the summit camera works for looking into the cylinders, can't see walls with it, just the top of Pistons.

joe_padavano

No Olds ever required shims from the factory, so unless this is an aftermarket distributor that is made incorrectly, there is no reason to use shims. The tooth angle and rotation direction on the distributor gear imparts an upward force to the Olds distributor shaft. That surface doesn't see any real wear under normal use.

oldcutlass

Ummm, I believe thats chebby that forces the distributor shaft up. Olds is drawn down.

Gary M

It's a factory distributor. Appears to have been rubbing.
Gear looks like wear consistent with counter clockwise rotation.

Gary M

The shims at summit are not for a 455.

oldcutlass

The shims are for a gm distributor, check ID before purchase.

foo

This is the same issue I was talking about in my post too with it rubbing

Gary M

Does your distributor gear have wear on it like mine?

foo

It does, here is the thread


https://classicoldsmobile.com/forums...nce-issue.html

Gary M

I'm going to measure from that ledge to the top surface of the block and compare it to the measure of the distributor from bottom of gear ( while shaft is pushed down) and surface of distributor that rests on block. Will post tonight.

Gary M

Did GM use a gasket between the block and distributor

oldcutlass

No, the O ring is the seal.

Gary M

That's what I thought but just ruling it out.
Maybe the distributor shaft has a way like a bushing or washer to prevent the shaft from dropping too far and has worn left out or been installed wrong.

foo

I have to rule that out cause mine are brand new and they still touch, have not done any other investigation into it yet though due to other issues ive come acrossed

oldcutlass

Don't know, I have only seen this once or twice in Chevy's. Usually after the block was milled, since the manifold is lower, so would the distributor. Olds doesn't have that issue.

foo

what about that washer between the gear and shaft would that be a cause?

Gary M

Since the shaft is drawn down into the motor as the engine runs, that washer is not the issue. IMO.

oldcutlass

No that just limits up movement.

Gary M

Both mine have a washer , the rebuilt one and the one in the car. How thick you figure that washer is?

Gary M

Obviously the block hasn't changed. Doubt the distributor shaft got longer. 40+ year old dist housing with a shaft spinning on it and pulling down all that time. Seems like maybe a washer up top may help if the housing wor down but I would think if shimmed up too much it would change the timing some. I should add that I don't even know what the inside of the distributor looks like past the plate the points mount onto. Just guessing.

foo

My thoughts if all else fails, grind the bottom of the gear a touch

Gary M

I put two different distributors into a 455 block I have and the gears ride on the block ledge with both. You can pull up on the part of the distributor that the weights mount to but the very center shaft of the distributor stays firm. Apparently the distributors have a center shaft and an outer shaft that the weights mount to as well as the lobes that open the points. It was mentioned about an oil port so could it be the gear/ block mating area is not getting enough oil?
also maybe that washer foo asked about is relevant. This is way above my head.

Gary M

from what I saw, you can grind off the bottom but it still will touch that ledge unless you remove enough.

Gary M

Took washer between distributor housing and gear out. Washer heavily worn. Looks like with the distributor installed using the washer the gear is jammed between that block plateau and the dist housing. Next picture is without the washer and distributor gear will contact the housing if pushed up. Have not installed the distributor yet.

foo

I happen to look at mine a few mins. ago and yeah it definitely rubbed a decent groove. I took it out aswell, though it can still touch the block (checked using very thin layer of grease on the bottom of the gear) it now has a little free room to go up

64Rocket

The way I found out to remove material off the bottom of the gear.
I install the dist in the block with out a cam. then tighten it down as normal.
If it turn free you are good. If no turn or very tight, remove material from the gear. In the gasket set, there is a paper gasket to fit over the dist, I trim it to fit in the recess for the dist in the block, it works as a shim for me.
Works for me.

Gene

Gary M

I bought some shims from Dick Miller Racing. .048 thick each but have not had time to install them.