engine balancing
08-29-2010, 11:57 PM
#1
Staging Lane
Thread Starter
iTrader: (2)
Join Date: Sep 2009
Posts: 86
Likes: 0
Received 0 Likes
on
0 Posts
engine balancing Just bought a short block. It looks good and clean.
The problem i have now is it was a third party trade from one guy to pay for another item. Now I have it and it has been freshly rebuilt with forged pistons and h beam rods on a stock crank.
I am concerned about the balance of it all since the seller did not know much history and when asking the previous owner the information is now much either.
Can I just weigh the rod and piston sets and be good or do i need a shop to do the complete rotating assembly together and make sure the sets are balanced to the crank?
I know these engines are sensitive to this and need to be close to a perfect balance as possible. any help would be great.
The problem i have now is it was a third party trade from one guy to pay for another item. Now I have it and it has been freshly rebuilt with forged pistons and h beam rods on a stock crank.
I am concerned about the balance of it all since the seller did not know much history and when asking the previous owner the information is now much either.
Can I just weigh the rod and piston sets and be good or do i need a shop to do the complete rotating assembly together and make sure the sets are balanced to the crank?
I know these engines are sensitive to this and need to be close to a perfect balance as possible. any help would be great.
08-30-2010, 12:17 AM
#2
If you're worried about it, you should send the rotating assembly to a shop to check the balance. It's not really one of those things you can do at home. They will weigh the pistons, pins, rings, rod big end and small end, and bearings to calculate a bobweight.
They will then use that bobweight to spin the crank on the balancer to see how close it is. Most likely, it will be off a few grams simply because it's a different machine and different operator. The slightest change in the setup can change the balance of the crank a gram or two.
Before any of that, if you look at the crank and see some fresh holes drilled into the circumfrence of the counterweights, theres a good chance it's been balanced for the new assembly.
They will then use that bobweight to spin the crank on the balancer to see how close it is. Most likely, it will be off a few grams simply because it's a different machine and different operator. The slightest change in the setup can change the balance of the crank a gram or two.
Before any of that, if you look at the crank and see some fresh holes drilled into the circumfrence of the counterweights, theres a good chance it's been balanced for the new assembly.