Crank Polish?

[Jacototheb]

Hello everyone. I'm back. Been gone for a long time for a lot of different reasons. But I'm just now starting to work on my car again. About to regasket the motor. Get the head milled, hone the block, and all that jazz. I've got an hx35 to go on my KA and I'm collecting all the supporting mods, but I was wondering if getting my crank pollished would be neccesary/usful since I'm already taking the motor to the machine shop.

[darens13]

i would just ask the guys at the machine shop to see what they think. i would say unless you spun a bearing or the crank was chewed up it wouldn't be necessary. it would be pretty cool to get the whole rotating assembly balanced.

[sandcrabsailor]

I've heard differing things about polishing the crank. Some say good, some say bad, some say it's GRINDING that's bad, but polishing is ok. I would give a +1 to darens13 for the "verify with the shop guy" idea.

[Jacototheb]

I haven't spun a bearing, but I wanted to get a new main bearing just to be safe. I'm going to go ahead and get it polished, and ask the shop what size main bearing I'll need to put back in. I would get the assembly balanced but it's over $100 and I'm using the same internals so I'm not sure it would need it.

Thanks for the help!

[sandcrabsailor]

If you have the opportunity to balance the assembly, DO IT.

[Jacototheb]

If you have the opportunity to balance the assembly, DO IT.

What are the benifits? I've never really researched it.

[sandcrabsailor]

It is recommended for high-revving engine, and you can tell a difference when you drive a car that is balanced, and one that isn't. Throttle response is immediate, and the RPM's are smooth and quick. It doesn't stay in gear long, goes right through them, and when you get into it, it goes.
If you got the chance to do it, get it done. The car is so much better.
Whether or not you get a new crank doesn't have anything to do with the need for balancing. If you change the pistons or rods, then the stock balance job is no longer valid. You can have it balanced with the stock or aftermarket crank.
Balancing an engine will not make more power or give it more response. Balancing is mainly a reliability step that will make bearings and the crank last longer. The higher you rev the engine, the more critical the balance is.

(blatantly plagerized from LS1tech forums)

[1KleenS13]

If the journals look good (ie, no scratches or deep groves) you probably dont need to have it polished. If you have a new rotating assembly you should defiantly have it balanced, if not a motor will tear itself apart. Every motor should be balanced, I dont care if its a 1.3L Geo it still needs to be balanced.