crankshaft question?

[jdmkiller]

just took a b20z crank to a machine shop today, and the guy sayed it was out of round and needed to be turned. he said it would be ten over when its done. not sure what he means, cuz ACL bearins only come in std, .025 and .25. so im not sure what bearings i need to get?

[Black4DrEK]

10 over means 10 thousanths of an inch. So in that case you will need oversized bearings. I THINK honda has lots of different bearing sizes. you might want to get OEM bearings. ACL also might, Just probly didnt list them.

[Black4DrEK]

Also.. Im sure Clevite will have the Exact size you need!! Ask the machine shop about the Clevite bearings or ect.. You can probly just order bearings straight from the shop.. Maybe with a discount. lol

[EmminoDaGreat]

Don't turn the crank, Just pick up another one, and check it out. Turning these cranks can weaken them, and depending on your application this may or may not be a problem in the future. I believe you can turn it very slightly and the treatment from factory is still there, but I am unsure of the depth. A b20/ls crank is 100$ all day. Probably cheaper than the machining.

Just my 2 cent's take it for what its worth.

But just for an example .50 mm is .020 (probably .019xxx) inches. So yes, your 10 10 (.009in)bearings should in theory be .25mm oversized, yielding you the correct bearing clearances if everything is machined properly

[Black4DrEK]

Don't turn the crank, Just pick up another one, and check it out. Turning these cranks can weaken them, and depending on your application this may or may not be a problem in the future. I believe you can turn it very slightly and the treatment from factory is still there, but I am unsure of the depth. A b20/ls crank is 100$ all day. Probably cheaper than the machining.

Just my 2 cent's take it for what its worth.

But just for an example .50 mm is .020 (probably .019xxx) inches. So yes, your 10 10 (.009in)bearings should in theory be .25mm oversized, yielding you the correct bearing clearances if everything is machined properly

Its a hit or miss thing, When turning honda crankshafts.. TONS of people have done it. BOOST, NX, ALL MOTOR, its ALL been done with Turned cranks. Some last forever, Some dont. Hell, A stock crankshaft can split. Its just Hit or Miss.

[EmminoDaGreat]

I have seen 1 Honda crankshaft break, Ever. And it was because it had been ran with no oil for a while.

I have seen multiple turned cranks pose issues. Not worth the headache.

[h22 jones]

I can honestly say i ran a turned crank when i was 16 with no problems but i dont recomend doing it . See machine shops have what they call standar limits and they can be to tight or to loose. I would not be as so much worried about the strenght of the crank as you cant get one done right and get the right bearings for it . I just tore one down built with a turned crank by another builder just to check it out because it had alot of problems . Bearings were so tight no way it would have made it through break in . Save yourself time and money and buy a good stock crank man.

[Black4DrEK]

I agree. Its not the best thing to do. Im under the impression, He has already done it tho. from the OP