Clearance Question

[carhell]

Just got my engine back from the machine shop and was wondering if the rod and main clearances are acceptable. They set them @.0024. This is a 50/50 street/strip car, maybe more strip time actually. I have read more like .0018 to .0020 is where I should be, but before I put it in I wanted to get a few opinions. I can take it back to the machine shop if need be. Thanks, Shawn

 

[onefastcar]

How much horespower or 1/4's you talkin about, little more info.

 

[Alky V6]

With an iron block at 450+ HP, that's where I would put it. If it's an aluminum block, you might want the mains at the clearance you stated.

 

[Nick Micale]

I agree with Don, most people look at the Buick factory specs that cover all the V-6 engine including the "economy" models. Your performance build needs more clearances like stated in the Buick Power Source manual.

With these clearances, as with any performance build, proper oil flow and type of oil is very important.

 

[johnplogii]

So what are the desired clearances for rods & mains? Iron block,stock crank, billet center caps & girdle.low 10 sec car? I will be assembling my short block today or tommorrow. Thanks

 

[carhell]

more info

How much horespower or 1/4's you talkin about, little more info.

It has around 475 hp and high 10 low 11 second range with stock crank(10/10). Also JE pistons, stock rods, champion aluminum heads, iron block, 116 cam. Thanks, Shawn

 

[Alky V6]

Buick Power Source recommends:
Main bearing clearance 0.0022-0.0027"
Connecting rod bearing 0.0018-0.0022"

The above is a very good recommendation for your setup. I've run a little more on the rods and mains with no problem. Post inspection of the bearings looked like new.

Like Nick said before, it is very important to match the oil you end up using with the clearances that you go with. Generally, more clearance, heavier oil.

 

[Alky V6]

With an iron block at 450+ HP, that's where I would put it. If it's an aluminum block, you might want the mains at the clearance you stated.

Correction: If it's an aluminum block, you might want the mains at the tighter clearance you stated.

 

[gnxtc2]

Correction: If it's an aluminum block, you might want the mains at the tighter clearance you stated.

Hopefully you mean cold/room temp.

Billy T.
gnxtc2@aol.com

 

[Alky V6]

Hopefully you mean cold/room temp.

Billy T.
gnxtc2@aol.com

Yes Billy. That's at room temp. People aren't starting to check clearances at operating temps, are they? :tongue:
Actually, I've run aluminum block main clearances larger (0.0028") with no problem.

 

[carhell]

is this ok

Yes Billy. That's at room temp. People aren't starting to check clearances at operating temps, are they? :tongue:
Actually, I've run aluminum block main clearances larger (0.0028") with no problem.

So what I am asking is with my iron block, 475 hp, high second GN, would
.0024 clearance on the rod and mains be allright? Thanks, Shawn

 

[Alky V6]

So what I am asking is with my iron block, 475 hp, high second GN, would
.0024 clearance on the rod and mains be allright? Thanks, Shawn

That will work fine. I would use Racing 20w-50 Valvoline.