I am rebuilding my second LT1. The first one I did I Bought a 4-bolt block that was already ready to go. Just bolted everything to it with new bearings and everything else and it was good. My question with this one is the check ball in the back of the block. I pulled the motor apart and sent the block to the machine shop and I have it back but I didn't check on the ball bearing to see if it was still in there. Has anyone ran the motor without that ball bearing? I have the LT1/LT4 book and it says that a bad leak at the rear main and possibly low oil pressure will result if its not in there. Just curious. I have the bottom end mostly done but not a big deal if I need to pull it back down to get that thing back in. Thanks.

 

Well, a bad oil leak and low oil pressure doesn't really sound healthy for your new motor. It's either pull it apart now or possibly pull the completed motor apart later. You choose.

Jeremy

 

that wasn't really what I was looking for! What I was wanting was somone that has experience with building the bottom end themselves and has either gone without the bearing plug or done something different to make it work.
I don't remember seeing that plug in my other motor.

 

I assume you mean the pipe plug under the rear main cap, not a ball bearing...

That plug directs oil to the filter, so if it is missing, you have a passive filter system at best.

 

yes thats the one. What does that look like? is it a ball or a threaded plug?
Thanks for the info!

 

It is a cupped press in plug, I forget the size, maybe the same as the front oil galley plugs?

 

I was watching for that too, when I had my block machined. I had removed the ball myself and didn't give it to the machine shop. When I picked it up from the shop (it was a bare block) I went over it with the machinist and he showed me a cupped plug he installed in there for me. It takes the place of the ball.

Anyway, you can either stick a long rod down the hole in the top of the block and see if something is in there or call the shop and see if there is a plug in it. If they did the galley plugs & freeze plugs, chances are they put that plug in there as well, or if you are feeling lucky, you can assemble the oil pump & pan and use a priming tool and see if you have oil pressure.

 

Are these available at any parts store? I don't think the machine shop put one in nor did they give me back the part. They took out all the block freeze plugs So I assume they took it out too and didn't replace with anything. I put in the new freeze plugs. Do either of you guys have pic of this thing?
Also if there is nothing in the hole can you see through the block like the oil shaft hole or does it stop about 1-2 in below the bearing surface.
Thanks again for all the help. don't want to screw this up. Its not my motor and I don't want to have to redo it.

 

If you go to buy it. it will probably be part of a kit, if you go to a shop that does engines, it will probably be 50 cents, if they charge you at all.

 

http://www.sdpc2000.com/faq/kbhowto.asp?mt_node=4
http://www.sallee-chevrolet.com/Disc...html?920140702
Alot of times those don't get removed for cleaning.
Depending on how far together you have it, you may be able to tell by blowing air through the passages.

 

I will find out what what size plug it is tomorrow, any decent machine shop will have them in stock, Napa might even have them.

 

Yeah nothing like not filtering your oil....

Bret

 

After seeing that diagram that explains everything! Thanks
The machine shop didn't remove it. I checked the passage last night and it was blocked. and thanks to the rest of you who chimed in on this post!

 

That's not necessarily good. A lot of junk can be trapped in that area - that's the whole point of taking it out before hot tanking and shot blasting. Hope you shot it out with a pressure washer or something. I can't believe they didn't take it out of there for cleaning.

 

The machine shop hot tanked it!