-TheBandit-

iTrader: (1)

The machine shop checked all my bearing clearances for me and came up with:

Mains: 0.0011in (Clevite P spec 0.0002-0.0018)
Rods: 0.0021in (Clevite P spec 0.0012-0.0037)

Both are about in the middle of the Clevite specifications, but the Clevite spec for the mains sure seems tight by performance standards. Do people actually follow the Clevite recommended clearances?

The engine is an LY6 iron block, L92 heads, stock crank, compstar rods, wiseco pistons, 10.25:1 compression, 227/235 .614/.621 113LSA, full length headers, and LS3 intake going into '70 Nova for primarily street and some autocross use. The mains are studded and were line honed. I do not plan to run nitrous or boost.

Do you think these clearances are ok for this combo?

bww3588

iTrader: (49)

I like to see about .002 on the mains and .0025 on the rods. A quick crank polish should take care of the tight clearances.

Gray86hatch

iTrader: (83)

Iron block go. 0025 on the mains and same on rods

Alum block. 0019-.002 on the main and. 0025 on the rods

Tim

Sales2@Texas-speed

iTrader: (5)

I wouldn't have much of any issue with that rod clearance, but the mains I'd likely go with an X bearing to get closer to .0021" or so (assuming you don't want to have journals polished or any machining on block to loosen it up).

machinistone

As was said, use X bearings to open up the main clearance to .0016"-.002" - but I never go more than that on an aluminum block unless it's a drag race application. You can mix shells in STD and X in order to split the difference.

Your machine shop should not try to polish more than .0002" out of a crank journal to gain clearance, it will always cut more out of the middle due to the nature of the belts.

.002" on the rods is fine.

-TheBandit-

iTrader: (1)

Thanks for the advice. So I would replace my MS-2199P bearings with MS-2199HX for 0.001in more clearance, right?

bww3588

iTrader: (49)

I just got my engine back from the machine shop today. They set the main clearances at .0017 with the p's and .0028 on the rods with the h's

machinistone

That will be fine, little bit loose on the rods, but you'll never notice an issue.

bww3588

iTrader: (49)

Left loose for a nitrous hit.

machinistone

Gotcha, a little extra cushion never hurts.

bww3588

iTrader: (49)

Hoping so.

Che70velle

iTrader: (6)

I read that you are a machinist. Why don't you do your own work?

bww3588

iTrader: (49)

Me? If so I do not have the equipment. I ***** out all my work.

-TheBandit-

iTrader: (1)

If you're talking about me, I do some hobby machining and have a Bridgeport-style mill in my garage, but engine machine work is beyond my capabilities (both skill and equipment).

UPDATE

I ordered a set of MS-2199HX (add 0.001 clearance) main bearings. The machine shop measured the new clearances. Here are the before/after clearances (P vs. HX)

#: P/HX
1: .0015/.0026
2: .0010/.0024
3: .0010/.0025
4: .0012/.0025
5: .0011/.0026

From what I've been reading, the new clearances are spot on. I plan to measure them myself also to confirm.

Che70velle

iTrader: (6)

I'm sorry, I was referring to this quote. I should have been more specific. I had read in a different thread, that bww mentioned he was a machinist. I thought it was odd that he'd got his engine back from a machine shop, when he said he was a machinist.

Sales2@Texas-speed

iTrader: (5)

Those look good to me!

bww3588

iTrader: (49)

I am an ASE certified machinest, I just do not have the equipment. Once in a while I go to the local machine shop and help out, or work on my own stuff, but with this build I haven't had time to do it myself due to work and other family matters.

machinistone

That's perfect for your iron block.

Che70velle

iTrader: (6)

Yes Clint, those clearances look great. Sorry about the hi-jack.