I have never encountered such a dearth of information about an apparently very important piece. The Lt1 has a size specific ball berring driven into the oil passage under the rear main cap on the passanger side of the block. It must be removed for proper cleaning when the engine is rebuilt. Then reinstalled apparently to ensure proper oil pressure and oil routing in the lt1. Of course the machine shop lost the berring and I can not locate one. I have been to the dealer it is not on any of the exploded views an I have been unable to find any other refferences (part number or the actual size) online. The size is also important because it deturmines how deep the ball fits into the funnell shaped hole. I have Mike Mavrigians book where it shows a picture of him removing the ball but to mention of what it is actually called or what size it is it just says make sure you put it back in. I imagine anyone who has built an lt1 must have encountered this problem b4 if anyoine can help I would be gratefull.

 

i belive all small blocks are the same as far as the dia goes

 

Nope, this is an lt1 specific part.

 

never heard of it.......where does it go?

I have built a few LT1's........maybe I missed em or left them out

 

It goes in a hole that is under the rear main bearing cap. The popular "How to rebuild small block Chevy LT1/LT4 engines" shows a couple of pictures of it.

 

The hole where it goes is under the rear maincap where the oil pump bolts on. it goes all the way up to the top of the back of the block. in a regular small block it feeds the top of the engine oil including the oil pressure hole at rear base of the intake. for some reason the lt1 got a ball driven into the hole to block oil I have heard if you dont have it in your oil pressure will suck and you run the risk of spinning berrings.

 

yep

 

so this is a oil restrictor type of thing?

Maybe they have never come out....but I have never bothered with one personally. As for the book......I can't read, Maybe golen or one of the LT1 engine shops would have one

 

What would not putting this ball back in do to the motor? Lower oil pressure when warmed up, cold or both? Possible damage?
My engine builder is all 1st gen sbc's and I'd bet he didnt put that back in if he didnt know about it so it might explain some issues with me new motor....

(sorry for the semi-hijack)

 

yeah I am supprised there is not more information on it. i found out about it from a friend of guy who cooked his berrings. He told me to make sure I put one back in, so I looked into it. most engine builders have no idea it exhists but every lt1 got one.

 

There's a f-body specific junkyard that keeps getting posted on this site... can't remember the name though...

 

The ball is not a restrictor, it's a blockage of the oil passage designed to divert oil flow through the motor. Removal is required if you wish to thoroughly clean accumulated debris and possible contamination from the block before rebuilding. On earlier small blocks the passage was sealed with a small diameter expansion plug. In my experience, the expansion plug is seldom removed but failure to do so is to accept the likelihood that foreign and possibly damaging material is still in the block.

 

You can also use a small soft plug like what is used for the oil galleries. The oil presuure pushes down on it so it cant come loose or pop out. The ball howver does work the best.

Whatever you do dont forget to install a plug or a ball or you will be hating life.

 

If the machine shop lost it then they should be finding one for you not the other way around. If the ball is a blockage then why not just plug the hole with something? Either way it would be easier for the machine shop to get a LT1 core or call around other machine shops to get one or to get the part and then find something to replace it with. Is it just a BB like the check ***** in an automatic tranny? They should find somewhere to borrow one and then use it to compare other solutions like a BB, steel ball from a shotgun shell or something. Small stuff like that you need to get creative.

 

The issue is that the ball bearing is the size of a marble. It is not a small orifice, but essentially the total size of the main oil passage.

Has anyone tried to use the old style cup plug? I have a motor apart now, so I'll look to see if it is an appropriate size.