Crank Balancing Question
 

I just got by Scat forged stroker crank back from the machine shop & the sucker looks like a piece of Swiss cheese. The machinist drilled 10 deep holes in the front counter weight & 9 deep holes in the back counter weight - there are a couple of shallow holes in some of the others. I sent him my crank, Pioneer damper (28 oz.) flywheel & pressure plate. He said that he had to take all of that metal out to get it to balance. He also said that it may have been easier to balance if I had a 'neutral balance' damper. He felt that the damper threw everything out of balance & looking at the back of it, it has a big weight on one side of it. I have 3 questions. Does it sound like the machinist did right? Should I have gotten a 'neutral balance damper (I didn't know there was such a thing). Do other Scat owners have balancing issues?

Rick

Mike B. Where are you
 

Where's Mike Burch at? He'll answer both of my questions. When Mike speaks, people listen.

Rick

A few questions:

1) Did you ask SCAT what they recommend as far as balancing goes? When I purchased my rotating assembly, DSS recommended an imbalance of 28oz. They said that a 50oz imbalance would make the crank look like swiss cheese. So, I went with a Fluidampr 28oz imbalance damper, and Fidanza aluminum flywheel with the 28oz plate and ended up with very little drilling required.

2) Speaking of the flywheel...are you sure you provided your machinist with the 28oz counter weight and not the 50oz? This would throw things out of whack for sure.

3) Yes, there are neutral balance dampers.

E

If you have a very light piston/rod combo, most likely you might have been better off with neutral balance. I had mine done to 28 oz. but it would probably have been easy to go to 0.

i had my scat 351 crank balanced for my 50 oz fluidamper (off my 302)....they did drill out a considerable amount of metal, but nothing that would weaken the crank...nor does it look like swiss cheese. Actually, i consider it a bonus (less rotating mass). HOWEVER, what concerns me is the machinist stating that the "damper is throwing the balance out of whack". Cranks are available in zero balance, 28 oz and 50 oz.. What damper you pick will affect how much work goes into the balance, but any COMPETANT shop should have no problem balancing any of these combinations. (My shop charged me 200 bucks. They also used some heavy metal.) By the way, they also balanced my pressure plate after balancing the crank.

I had my eagle crank and rod 514 kit balanced with a zero balance balancer and hardly had to touch the crank. I think he should have mentioned it to you that a zero balance would benefit you. just my 2 cents..

All depends on what your bobweight is. Your situation is pretty normal. I just zero balanced my 302 forged Scat crank and it took 14 pieces of 1" mallory metal. That's pretty typical for a ford crank with a bobweight like mine. I know, the crank doesn't look very pretty when its done, but looks don't get you down the track.

hey Jeff
We are almost neighbors..