Screaming Metal
Active Member
Here's a little more info on balancing also....
http://www.hensonracingengines.com/Crankshaft_Balancing.html
http://www.f1technical.net/articles/4
I must be extremely blind and dunmb....I just read the part of the scanerio you just explained.....
-Let me try again. You have, say a 383 stroker. with super lite pistons and rods in it. So now you have lite bob weights on the crank and being it is a 383 with 3 3/4" stroke, you have an external balance flywheel. So you put it all together and it runs great and you take it to the track and break the flex plate. Now just to be the devils advocate here, you have no idea about the bob weight and can't even find the guy that built the motor or balanced the engine. How do you now balance a new flex plate to that engine without taking it apart and spinning the crank again. I understand about the strobe and the light and meter on the machine. I balanced 100s of engines back in the day. And back in the day we could not do what I just ask. I was wondering if there is a way to do it now?-
I can with a oscilliscope and probes attached to the front and rear of the crank (which senses vibration and feedback), not alot of shops can do this. Its time consuming and expensive....and the motor must be dyno mounted. Some folks spin the motor over with a big electric motor which they run in the motor with, without starting it. i have a big electric motor, but its for spinning the blowers to check bearing noises and boost pressures, etc.
The deal with the 400's and the 454's is once you loose your flywheel...if you balanced it to where the motors in balance with the 'stock' unit, you can set it up and 'copy' that balance, by 'weighing' in quadrants of the flywheel in question, and when doing so, doing it in relation to your lineup holle on the rear of your crank.
After balancing, you have a total weight, then you have 'quadrant' weight, so many degrees of that crank weight a 'X' amount, so-forth aroundthat crank. You can write all these numbers down and keep then in a folder, then when something blows the hell up, you can duplicate it. Same thing with the harmonic balancer.
http://www.hensonracingengines.com/Crankshaft_Balancing.html
http://www.f1technical.net/articles/4
I must be extremely blind and dunmb....I just read the part of the scanerio you just explained.....
-Let me try again. You have, say a 383 stroker. with super lite pistons and rods in it. So now you have lite bob weights on the crank and being it is a 383 with 3 3/4" stroke, you have an external balance flywheel. So you put it all together and it runs great and you take it to the track and break the flex plate. Now just to be the devils advocate here, you have no idea about the bob weight and can't even find the guy that built the motor or balanced the engine. How do you now balance a new flex plate to that engine without taking it apart and spinning the crank again. I understand about the strobe and the light and meter on the machine. I balanced 100s of engines back in the day. And back in the day we could not do what I just ask. I was wondering if there is a way to do it now?-
I can with a oscilliscope and probes attached to the front and rear of the crank (which senses vibration and feedback), not alot of shops can do this. Its time consuming and expensive....and the motor must be dyno mounted. Some folks spin the motor over with a big electric motor which they run in the motor with, without starting it. i have a big electric motor, but its for spinning the blowers to check bearing noises and boost pressures, etc.
The deal with the 400's and the 454's is once you loose your flywheel...if you balanced it to where the motors in balance with the 'stock' unit, you can set it up and 'copy' that balance, by 'weighing' in quadrants of the flywheel in question, and when doing so, doing it in relation to your lineup holle on the rear of your crank.
After balancing, you have a total weight, then you have 'quadrant' weight, so many degrees of that crank weight a 'X' amount, so-forth aroundthat crank. You can write all these numbers down and keep then in a folder, then when something blows the hell up, you can duplicate it. Same thing with the harmonic balancer.
