Balancing

[slick6732]

Whats up guys? I have read some much I think my eyes are about to bleed, cant find what I am looking for so I guess I will ask, I am sure it has probably been asked and answered 500 times. I just havent found the right thread.
I sent my crank away to be turned, The shop says they can do it 10/10 left on high side of tolerance. My questions is, How critical is balancing? The engine was rebuilt about 600 miles ago and balanced during rebuild and cheap rod and main bearings were used when it was re-assembled. If the shop is taking off equal amounts off of all journals, would the balance still be close enough to not have it balanced again?
The motor is out of 87 t-type, crank was stock sized until the junk bearing issue. Clevite 77, not american made.

All advice is appreciated !!!!!!

 

[TurboDave]

If it's already been balanced once, and you're re-using the same rods/pistons that were used on the previous balance, then I don't see why another balance would be needed.

If parts were being changed/interchanged then yes.

 

[slick6732]

Even with the crank being turned? Yes everything is going to stay the same internally, except new federal mogul bearings. If that is the case, life just got way easier!!!!!!

 

[charlief1]

Since you're only removing a small amount of matereal you should be fine. If you were polishing the throws then I'd yes, it need to be rebalanced.

 

[cruzn57]

if this is a race engine........

I'd balance it.
but if its a street eng, I wouldn't be so concerned.
your cutting .010 off ea rod journal, so crank is still balanced.
its the reciprocating weight that it affects, (but not much)
do what makes you sleep well, and enjoy it.


then there is the value of recip weight, is it 30%, or 50%, etc.

 

[williambavila]

Even with the crank being turned? Yes everything is going to stay the same internally, except new federal mogul bearings. If that is the case, life just got way easier!!!!!!

your going to be fine like charlie said.. your not removing enough material to cause a balance problem. if you are replacing any rods or pistons then yes but they should have given you a balance card with that the first time. so again its all ok. use some good bearings.. king bearings are super i have used them for years and they hold up great.

 

[slick6732]

King bearings keep coming up!!! Could you guys familiar with them possibly give me a part number for mains and rods or possibly a link. Went to their site and there is no Buick under model.
Thanks for the help from everyone !!!!

 

[williambavila]

King bearings keep coming up!!! Could you guys familiar with them possibly give me a part number for mains and rods or possibly a link. Went to their site and there is no Buick under model.
Thanks for the help from everyone !!!!

The3y are the best out there i used several sets while i built race motors in the machine shop. They have gone way up in price if you can wait until the morning i can send you prices and part # i have access to them still.the clevitte is a good bearing but king bearing has a bit softer surface...

 

[3.8L V-8 eater]

Sorry don't mean to hi-jack the thread,but how cridical is a stock flexplate to a balanced motor?? I just had the bottom end rebuilt and they found a crack in my flexplate which apears to have had a little weld added to the edge for what looked to be the purpose of balancing.... BTW, I had the engine builder use coated Calico bearings for rods, mains, and cam bearings.