Lethalwx69

My main oil clearances (using stock bolts) were right .003 in. Recently I decided to go with arp studs, which could tighten the clearance between .0005 in to .001 in. Is this ok without machining? If I could pull it off without machining or buying new bearing that would be awesome.

WTF?

I will tell you what I do in those cases......now, it might not be the accepted method as many people would rather just throw money at it, or get the crank polished. In a situation like this, I take some 2000 grit wet/dry paper, and submerge, and lightly polish the surfaces. I also have had to put the bearings in the block, torque down without the crank in, and polish the mating surfaces. Bearings that are too tight, are a nightmare, and usually spin bearings. Personally, I would polish wit paper, as opposed to buying .001 under bearings, or polishing the crank. But, I am fairly seasoned.
Good luck.

Paul Bell

iTrader: (9)

Finally, moving a thread INTO the internal engine section.

68Poncho

iTrader: (1)

Most engine builders would have the Mains line honed after application of the new studs. In your case the .003" was a bit loose which may have caused low oil pressure numbers. The tolerance from GM for the Mains is 0.0007"-0.00212". Assuming you are using a dial bore gauge and using it correctly, .0005" would be too tight thus requiring machining and probably new bearings.

bigdan1

I build hi performance engines since 35 years ......

main clearances of .003 is best for high revolution .....
I always manage my main bearings tolerance to obtain this specific .003

RezinTexas

3 thou is perfect for iron block LS mains. That is what my motor has and I have 55psi hot idle pressure.

Also, on the ARP studs, I just measured an LQ4 block mains before and after installing ARP studs. The distortion was limited to 3 tenths on the #5 main only.

roastin240

iTrader: (13)

I have also used this method to score an extra 0.0005 in clearance. It works and is quite minimal with respect to the material on the bearing. I typically do this to all the clearances that are smaller than the largest. If the largest is 0.002 in and the others are say for example between 0.0015 and 0.0019, i will lightly sand them with very very fine grit sand paper until they are all at the largest 0.002 in clearance. Applied this method to 10+ engines. That's how I roll.

Lethalwx69

Late post but thanks for all the info. I just bought a Melling high volume oil pump and called it a day.