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I just got my crank bask from being polished. It looked fine when I took it in and the guy who polished it said he didn't mic it; he just cleaned it up. The specs call for 3" on the mains and 2.4988-2.4998 on the rods. I checked all the journals with my dial indicator and here's what i got:
Mains: Rods:
1) 2.998 1) 2.4982
2) 2.998 2) 2.4992
3) 2.996 3) 2.4980
4) 2.995 4) 2.4980
5) 2.996
What do you think? Is this too far out of tolerance to use standard bearings?
It's .002-.005 under, with .0015 allowance for normal clearance that's up to 6 1/2 thousandths running clearance. A tad much I think. What engine is it? Some can stand more than others.
I'd take it to a good shop and have them mike it, dial indicators aren't accurate enough for crankshafts.
It's a 455 Olds; thanks for the good advice. I"ll have it checked by a pro. Too much time and money rebuilding an engine to take a chance. Maybe my dial is off and it's OK.
i have a hard time thinking he took off 005 with a belt ? yes the crank needs to be check with a mic at 70 temp when checking it .cold iron or steel. metal. will not read the same . i check the crank before and when i polished it .some engine s you can get 001 bearings. were i want to see oil clearance may not be the same whats ok in the book sbc rods can be 001.5to 003 on the hi side . that may be fine for racing but i do not care much for them that big for stock every day use.
Can' t imagine a shop polishing a crank without checking it first.
Like Pat sez, .0015-.002 is best for everyday use. They'll "clearance" themselves plenty soon enough!
Thanks guys; I called back the shop that did it and they are going to take care of it. They agreed; they should have checked it even though the work ticket just said to polish it.
if a 350 olds here is the list of spec s for oil clearance rods .0009/003.4 mains 0008/003.8 i see rods 2.1238/2.1248 mains 2.9990/3000. housing bore rods 2.2495/2.2500 main housing bore 3.1880/3.1890 . saying that they did not check it just polished it is B.S i think .how would you know what size it was ? i like to know what i am polishing and were it at for size to start with :) i have been doing it all wrong:D tell me the year and the engine size .them posted are for the 350 olds. out of the ..bible.. federal mogul engine bearing shop specification manual:D
Good news; the guy checked it and everything was within specs. You were right, Pope. A dial indicator wasn't accurate enough. Bearings are on the way; I feel much better.
Glad it worked out okay for you.