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Old 04-20-2009, 03:53 PM
olddog olddog is offline
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Join Date: May 2006
Location: St. Louisville, Oh
Cobra Make, Engine: A&C 67 427 cobra SB
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Quote:
Originally Posted by Prestidigitator View Post
So let’s say you take a motor that is smooth running and balanced and you take off either or BOTH the balancer and flex plate and you replace them the proper balancer and flex plate but that of a different manufacturer.

Are you saying that you would not notice the difference or that there would not be much if any difference in the running of the motor?

If you are saying yes to this question then that would mean that there really are no “combinations” that this guy can try, correct?
Yes. I think the differance in ballance would be negligable to a street car. In a race engine that is going to run 7-8K rpm all day, it could be the differance between finishing the race or not. Even then I would think you would have to be pushing the engine to near its limit before it would matter, and racers do push 'em to their limits.

Quote:
Originally Posted by Prestidigitator View Post
I know nothing of dynos, but assuming that the engine was dynoed where it would NOT be possible to tell if there was a balance issue, is it possible that the motor company could have built, dynoed and then boxed up the motor without realizing that it was out of balance? .
From what Keith said, a dyno operator should notice a ballance issue even if on solid mounts. You haven't realy said how bad the ballance issue is. The worse the problem the less likely this is it. You said this is a decent company, so this is not very likely, but I would not 100% rule it out. If all other possibilities are completely ruled out, this is what you will be left with.


Quote:
Originally Posted by Prestidigitator View Post
Also here is another scenario that has crossed my mind. Is it possible that they sent it out balanced correctly but it got handled rough in shipment and it sent it out of balance?
No. To ballance an engine, metal is remove (by drilling) or added (by welding in mallory metal) to the crankshaft. Nothing short of this will change the crank shaft. The damper on the front does have a rubber bushing (for lack of the correct term) that it is possible for the outer metal hub to slip. It happend to old deteriorated junk, but doubtful it could happen to a new one. Several people have mentioned that if the key is missing from the keyway on the damper, the damper could have rotated on the crank, causing it to be off ballance. This is a real possibility.


Good luck
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