BB

iTrader: (7)

If I put in ARP main studs, and have the mains align honed on a stock new LS6 block, should I expect to have to get different sized bearing over the stock size? IOW, can I expect the main bearing clearances to change?

Jason99T/A

iTrader: (21)

As long as the main housing bore diameter is within the factory spec (2.7508"-2.7515") after the align hone (it should be), then a stock bearing (STD) should be fine. However, depending on if the housing bore is on the looser or tighter side of the factory spec, this could necessitate the use of an oversize (+1) or an undersized (1X) bearing to get the bearing clearance within the desired range.

Journal size, bearing thickness, etc. play a role in your final bearing clearance as well.

Jason

Steve - Race Eng

iTrader: (1)

When you take the block for align honing make sure to take the shop your crankshaft and bearings. Have them check the bearing clearance during the align honing process. They can size the main bearing bores to give you the correct clearance with your bearings. It will cost a bit extra for their time but this will eliminate a lot of work and expense afterwards by not having to mess with over and under bearings to set the clearance.

Steve Demirjian
Race Engine Development

BOWTIE

Well, I am old school so I am not sure about the bearing selections for our LS1's. But on the old cast iron blocks, we would cut material either off of the cap and if necessary off of the block so that after the mains were honed, they were back to the original (factory) dimensions. I did do some work on a motorcycle (GSXR-1100) engine and it actually came with bearings with different housing bore diameters as well as journal diameters. That is the only time I have seen that. The good news, is that you would not need to remove much if any material just because you went to main studs. Most likely the housing bores will just be slightly out of round and a slight hone should bring them right in. On some old blocks with spun mains or badly warped blocks we had to cut them so much it would bring the main center closer to the cam requiring a shorter timing chain.

T/A Medic

iTrader: (1)

why would u have to do a align main hone on a brand new block? should all be squared away right?

Uthinkso

We align hone every single block before we do any assembly. We thought the same thing that they SHOULD be alright from the factory but we were seeing some that were tight and some that were big. For the cost to align hone a block it is buying piece of mind the way we see it.

Cutting the caps to tighten the main bore is something that has to be done sometimes. We hate to do that though because that starts to make the timing chain sloppy. Of course that also depends on how much was cut. Sometimes you can just lap the cap on a stone and get what you need.