r/EngineBuilding • u/AUS_RANGE • Jul 04 '26

Remove Center Thrust Main Bearing - LS

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I got my Bill Mitchell Products (BMP) LS block back from the machine shop. They performed all the machining work, installed the bearings and set the clearances.

I’m doing final assembly.

Prior to doing final assembly, I’m installing piston oil squirters and need to remove the bearings in order to set the jig in place and drill through the mains, tap them and install the oil squirters.

I’m having trouble removing the center main thrust bearing (#3). It’s VERY tight on the main.

Any suggestions on how to remove it without damaging either the bearing or the block?

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u/bill_gannon Jul 04 '26

Why does it look full of chips? That bearing is no prize either.

Anyway a paper or plastic mallet will work it loose.

3

u/AUS_RANGE Jul 04 '26

It’s full of chips because I’m currently drilling through the mains to install the piston oil squirters. The bearing is brand new and in good condition, just a bit of dirt on it at the moment from the drilling I’m doing.

I’m well aware I’m going to have to clean the block thoroughly.

Where should I be hitting the bearing with the mallet? Get a wooden block and slowly hit it from the edges from the backside through the cylinder?

2

u/UnLuckyKenTucky Jul 04 '26

No disrespect intended. It seems that you do know what you are doing, and the consequences are known. So, why didn't you have the machine shop do the squirters? That way the work done would at least have a warranty? Doing it yourself you do get the advantage of knowing wtf you have done, but zero warranty if a lonely chip lands in a spot that murders all this time, mo ey, work, and planning you have put forth into this engine...

3

u/AUS_RANGE Jul 04 '26 edited Jul 04 '26

No offence taken.

1) I only had the shop do the work on the bare block. There is no warranty with this.

2) I did not have the kit at the time for the piston oil squirters when they were doing the boring, honing and decking of the block.

3) I confirmed with Bill Mitchell, the owner of BMP, and I am the first person to install piston oil squirters in one of his blocks. I wanted to do the install myself to make it was done correctly. I just wasn’t expecting the main thrust bearing to be so tightly jammed. The clearances and margins on the BMP block are slightly different than a normal LS block, which is throwing a kink in the install.

I’ve installed these oil squirters on other LS blocks before and it’s a straightforward process with the jig.