Main bearing clearance

[Zach Baumann]

Just got my block back from the machine shop. And with what they did the main bearing clearance is at .0032, they said run 5w-50 and it’ll be good. This seems like a lot of clearance for our engines. I’ve tried looking into .001 less bearings but no luck. Also looking into bearing coatings to tighten it up a bit. Any ideas?

 

[Juice]

Meh, whats factory tolerance? Id run it.

 

[Midlife Crises]

I have seen Clevite bearings listed in 0.001” and 0.010” oversize for the mains and rods. I think they were H series bearings if I remember correctly.

 

[Zach Baumann]

Meh, whats factory tolerance? Id run it.

Factory spec for rebuild is between .001 and .002

 

[Zach Baumann]

I have seen Clevite bearings listed in 0.001” and 0.010” oversize for the mains and rods. I think they were H series bearings if I remember correctly.

I’m thinking of getting a set of those and mismatch to get the spec I want. I have the standard H series currently on the shelf.

 

[lwarrior1016]

A lot of machine shops set bearing clearances loose. Because, loose will run.

I highly suggest swapping bearings and getting it tighter. How do you run the car? How much power is it making?

My last coyote I built with .0015” on the mains and the rods, ran 5w-50, and it made 700whp. When I took it out for a sleeved block, the bearings looked brand new.

 

[Zach Baumann]

A lot of machine shops set bearing clearances loose. Because, loose will run.

I highly suggest swapping bearings and getting it tighter. How do you run the car? How much power is it making?

My last coyote I built with .0015” on the mains and the rods, ran 5w-50, and it made 700whp. When I took it out for a sleeved block, the bearings looked brand new.

I’m building it for a blower ~500hp but it won’t be put on right away. So from my understanding I need undersized bearings to tighten it up?

 

[lwarrior1016]

I’m building it for a blower ~500hp but it won’t be put on right away. So from my understanding I need undersized bearings to tighten it up?

That should be correct. Get a set of .001” under bearings and give those a shot. If they’re too tight, you can half them with standard bearings. But if you half them, all of them need to be half.

Like if you half the mains, then all of them on the block side have to be half, while the caps will be standard.

 

[Zach Baumann]

That should be correct. Get a set of .001” under bearings and give those a shot. If they’re too tight, you can half them with standard bearings. But if you half them, all of them need to be half.

Like if you half the mains, then all of them on the block side have to be half, while the caps will be standard.

Understood. Unfortunately it looks like all .001 under are on back order until August.

 

[lwarrior1016]

Understood. Unfortunately it looks like all .001 under are on back order until August.

Where all have you checked?

 

[Zach Baumann]

Where all have you checked?

Rockauto, JEGS, Summit, MMR, ModMax, Modular Head shop, Amazon, Walmart online

Lethal performance has them but they are $258 where all others are ~$120. Might just have to bite the bullet and pay the extra.

 

[Midlife Crises]

A little more looking and I see that the oversize bearings are made 0.010” tighter and are to be used when the crank has a little turned of the journals to clean them up. I have used 10-10 cranks in the past. The 0.001” undersized bearings are to be used to add more clearance (looser). Might explain why the 0.010” bearings are more common and in stock while the 0.001” bearings are on back order everywhere. Just to add confusion I see King bearings data on bearings oversized on the OD for use where rods have been repaired. I am only trying to point out you have to be really carful when ordering what you think you're ordering.

 

[Zach Baumann]

A little more looking and I see that the oversize bearings are made 0.010” tighter and are to be used when the crank has a little turned of the journals to clean them up. I have used 10-10 cranks in the past. The 0.001” undersized bearings are to be used to add more clearance (looser). Might explain why the 0.010” bearings are more common and in stock while the 0.001” bearings are on back order everywhere. Just to add confusion I see King bearings data on bearings oversized on the OD for use where rods have been repaired. I am only trying to point out you have to be really carful when ordering what you think you're ordering.

I appreciate it. Definitely have more research to do.

 

[lwarrior1016]

I appreciate it. Definitely have more research to do.

Did you call Dale at modmax? I just called him today and he found me a set of .001” under main bearings for my coyote. You have to call though, he’s got a bunch of different sources he can check.

He is extension #500. Really man, if anyone can find them, it’ll be him.

 

[lwarrior1016]

My main bearings today, checked at .003” using king XP bearings. So we went with a .001” under. I’m trying to get .002” out of it.

 

[Zach Baumann]

Did you call Dale at modmax? I just called him today and he found me a set of .001” under main bearings for my coyote. You have to call though, he’s got a bunch of different sources he can check.

He is extension #500. Really man, if anyone can find them, it’ll be him.

Will definitely do this. I can’t find them at a reasonable price. So before over paying I’ll do that. Thank you

 

[Zach Baumann]

No one has these bearings. The site where they were priced high is also out.

 

[lwarrior1016]

No one has these bearings. The site where they were priced high is also out.

Damn. I’m sorry to hear that. Dale was able to find me the last set of king mains for my coyote.