I am building a LQ4 and running into a problem. My stock crank and stock block is showing .001 clearance on the mains when checking with plastigage. to double check , I had the machine shop check the front main with a cylinder bore dial and micrometer and he measured .0012 . I am aiming for the high in of the clearance for more oil wedge so I find this not acceptable. Stock specs are .0008-.0025 for service specs.
Thoughts???

 

I would wonder why they are so tight in the first place. 0.0024 - 0.0027 is what people shoot for in performance builds. What bearings are in it?

 

I am using the sealed power stock48 suggested and he says that he never seen one come up this tight. It is in stock specs and this is a low mile engine so its possible that its just this tight. One explanation is I am in south I measured the journal surface in the garage at 91° yesterday. Machine work tolerance work is normally checked at a lab environment of 72° which could have my tolerances reading. 0005 tighter according to a car craft article on the subject. I have a thinner bearing on the way and the engine has been moved to the living room! Will report findings...

 

That is a little tight. I like to see .0015~.0018 and .002'' at the most @72 deg. It's just kind of hard to tell what you have going on without me checking it myself. I always know exact crank dia, main housing bore before I start assembly. I can tell you the cranks are usually right on and main bore can be all over the place. Head tq can change main journal dia as well, as main bearing tq, and cross bolt tq.

 

Componets are in the house for a 24hour period and thinner main bearings will be picked up at lunch. Many tests will go down tonight in the comfort of the central hvac system. Muhahaha

^^^Lemme borrow that Nova, need to make a lil mod money on the back road. ^^^

 

Did you use ARP main studs? They have a different clamping force, and you might need machine work to correct this. I needed it.

 

Stock block
crank
bolts

 

DO YOUR TESTING AT 72 DEGREES
Metal temp changed from 91 to 78 by bringing the project indoors.Went from .0001 to .0017 and I still don't have the metal down to the recommended 72*. That coupled with the fact that plastigage runs tight anyhow makes me feel better about moving forward. Mostly posting this so others can find the info if somebody searches the topic like I have been. THANKS to stock48 and to CarCraft where I found the temp article.

 

Glad it is moving in the right direction. For some reason women dont usually like to see engine parts in the house. How did this go over?

 

I cleared it with the wife first. It was that or run a window unit in the garage for 2 days. Much cheaper to bring it in. Was nice not to sweat so much as well. She is really very understanding considering her lack of interest.