lhaitzss

iTrader: (27)

I have searched but can't find a concrete answer. He is what I got:
Speed pro 152M main bearings
Callies Crank with stands main size just polished
I measured with plastigauge each main and have come up with the following measurements:
#1-.0018
#2-.0020
#3-.0018
#4-.0018
#5-.0020
I have read that some think it to tight and some think just right. If I go with an oversize of
.001 that will put two of my bearing clearances at .0030. For a street motor from what I have read is too much?
My rods were sized to crank with a perfect .0025 clearance on all of them.
I plan on running Mobil 0-W40 full synthetic after break in. What are some thoughts about these bearing clearances. Thanks

Just got finished measuring the mains with the dial bore. Measurements came in at
.0020-.0021 across the board. From the info gathered this seems to be in the ball park. Thanks again for the the replys.

pwtr02ss

iTrader: (33)

I think it'll be fine to run at that. These seem to like closer main bering tolerances

382ssz28

iTrader: (24)

I believe the manual says .0015-.0019. I'm in Detroit today and the manual is 300 miles away. Where is your manual, BTW? Big blocks like .003" and high reving small blocks. These motors are very tight.

J&J Speed Shop

iTrader: (8)

DO NOT, I REPEAT DO NOT use the X(.001+) bearings. You are already on the loose side of things for an aluminum block. Did you buy the crankshaft new? Do you have a way to mic the journals and use a bore gauge on the mains. Plastigauge is an okay estimate but solid numbers are better

KCS

iTrader: (20)

A general rule of thumb is about .001" for every inch of shaft diameter, so .0025" on the mains would be fine, +/- .0003". You could use a combination of STD and X bearings to get you there, but I wouldn't trust plastiguage on a lawnmower engine.

If it were mine, I'd leave the STD's in there and have the crank ground to get your clearance. That way you know the journals are straight and round, the clearances would be perfect (assuming the crank grinder is good and measurements are accurate), and you don't have to mess with two sets of bearings. With Clevites, I've seen a tendency for Compstar cranks to be on the tight side, even with x bearings.

ATwelveSec02Z28

iTrader: (17)

Those clearances are fine especially on an aluminum block. And J&J is dead on - plastigage is an estimate ONLY, use a micrometer on everything - just be careful not to scratch the bearings or journals.

bonestock99

iTrader: (1)

Do yourself a favor and if you want the money you are putting into the engine to BURN away then DON"T USE PLASTIGUAGE!! But if you measure with a bore guage on our race motors we run .0018-.0022 clearance so that should be fine. By the way our motors spin 9000 for several hours at a time.

lhaitzss

iTrader: (27)

Just ordered dial bore gauge set from snap-on. I tried t-gauges but they suck *** trying to get an accurate reading in a round hole. Should have by next week. i will report back with correct readings. Thanks for all the replys.

KCS

iTrader: (20)

Oooo, how much did that run ya, if you don't mind me asking?

burntblkZ

iTrader: (5)

I used plastigauge on mine and came up with .0028 which i thought was a little loose. Had a friend come over and mic everything and he came up with .0022. Ill never use that crap on my own stuff ever again. Real numbers are real clearences, dont trust how much you can compress plastic to get an accurate reading.

lhaitzss

iTrader: (27)

The kit ran about $320.00. Tool prices don't matter as long as it gets done right. I will also use it in the future.

KCS

iTrader: (20)

Not bad, I would have thought Snap On would bend you over. Do you have mic's already?

lhaitzss

iTrader: (27)

Yeah I bought an assortment from them last year when I wanted to build an engine.

lhaitzss

iTrader: (27)

Updated measurements. Thanks again.

67Ranger

iTrader: (16)

that should be fine, especially on an aluminum block.