engine bearing clearances? piston ring gaps? looking for ideal clearances for street/strip engine.

[black-is-back]

as the title states im in the process of a rebuild due to a blown headgasket thus resulting in worn main and rod bearings...before i bring the block to my local machine shop i would like some info on what bearing clearances, piston to wall clearance and piston ring gaps you pros use for a reliable engine...the machinist doing the engine said he rebuilt a number of these motors back in the late 90's, but just to be sure id like these clearances from anyone who has built these engines successfully so i can compare and see if he knows what he talking about. the car will mostly be a street car with occasional trips to the drag strip. only thing im adding to the block is .30 over speed pro forged pistons. any responses are much appreciated. thankyou.

 

[Nick Micale]

Not sure what your motive is here, but if you do not trust your engine builder, find one you can trust.

Engine specs vary depending on use and HP level, type of parts, oiling system and other variables.

The stock Buick turbo V-6 engine clearances are the same as a carb V-6, and performance specs are all over the place?

You have TRW pistons, follow the manufacturer's specs.

What really matters is the builder's knowledge, ability and willingness to do a "perfect" job!

 

[jasjamz]

I see you're in Jersey. I think you can find a well known Buick builder in that area and reviews of their work on this board. Late 90's since he did some Turbo Buick work...I would avoid him. You should never have to do this for him to build your motor. I don't care if he has a 1200hp 707ci motor in the back room. He may screw yours up.

 

[EVIL]

Not sure what your motive is here, but if you do not trust your engine builder, find one you can trust.

Engine specs vary depending on use and HP level, type of parts, oiling system and other variables.

The stock Buick turbo V-6 engine clearances are the same as a carb V-6, and performance specs are all over the place?

You have TRW pistons, follow the manufacturer's specs.

What really matters is the builder's knowledge, ability and willingness to do a "perfect" job!

I've seen this similar response to this question in the past. Even though I understand your answer, these engines have been proven to be a different kind of beast and I don't see why getting a few pointers for a good machinist is a bad thing.

D

 

[mtocrs1]

The old Buick Powersource Book lists the mains from .0021 to .0025
Rods .0023
But it should be up to the person building it.

 

[fastblackracing]

Is this going to be a mostly stock type rebuild? Does the crankshaft need ground,does it need align honed, what type cam do you intend to use? Give us a bit more info to work with.

 

[mtocrs1]

More info
http://www.vortexbuicks-etc.com/factory_engine_specs.htm

 

[black-is-back]

well the engine will be mostly street driven very often and occasional trips to the track. cam is a edelbrock 204/214 flat tappet, kirbans valve springs, mildly ported heads, te44, 3'' th downpipe, razors alky kit with 60lb injectors and tt chip..yes the crank needs to be cut 10/10...these are the basics...there are a couple more supporting things..but basically a mid to high 11 second street car is what im after...any advice from an experienced engine builder would be great..

only reason im using this machine shop is because the owner is a friend of mine and ive been dealing with him for years and years..he's done a dozen motors for me ranging from 454 big blocks to 355 windsors over the years...he's charging me an incredible price to do the motor, less than half what cottons and some other big names quoted me...i know it may be a hit or miss in some of your eyes but hey if i can get this motor done, make sure he's doing it rite and maybe give him a few pointers...central jersey may have a new turbo buick builder...

 

[trixdout]

as the title states im in the process of a rebuild due to a blown headgasket thus resulting in worn main and rod bearings...before i bring the block to my local machine shop i would like some info on what bearing clearances, piston to wall clearance and piston ring gaps you pros use for a reliable engine...the machinist doing the engine said he rebuilt a number of these motors back in the late 90's, but just to be sure id like these clearances from anyone who has built these engines successfully so i can compare and see if he knows what he talking about. the car will mostly be a street car with occasional trips to the drag strip. only thing im adding to the block is .30 over speed pro forged pistons. any responses are much appreciated. thankyou.

I'm in the same situation as you are and would love to know these specs as well and what people recommend.

If you don't mind me asking a few questions as well, I think we can both benefit.

What would benefit a stock cam, stock crank, forged trw pistons, stock valvetrain except for vsprings and let them be comp 980's or 981's and possibly running meth on this setup sometime in the future?

 

[fastblackracing]

Your clearances end up being a result of the machine work-- does the guy take it to the high end of spec or low end or does he even care? Once the parts are machined you cant adjust anything to make the bearings tighter, This is why you need a machine shop that is experienced with our little v-6 motors. If the clearances are too loose you will have lower oil pressure and not much you can do about it. I have had good results with using .0015-.0018 0n the mains and .0019-.0021 on the rod bearings. Crank thrust .006-.008 is ok. Piston to wall should be the lower side of what your set reccomends, and ring gaps if your using file fit I like .018 on the top and .015 on the second ring. This has worked good for me with engines making up to 500-550 HP. You will also want to make sure and use a good front cover/ oil pump, a lot of them have damage or scoring in the gear pockets that will hurt oil pressure. You should also make sure the camshaft turns freely with no binding, most dont check the cam bearings, they should be around .0015-.0020. hth