This may be an old question, but I don't know the answer and maybe some of the great readers of this board can set me straight. I know the 302 is externally balanced and there are two different balance weights. I also know that the different weight flywheels and harmonic balancers should not be used together. What I am unsure of, however, is can you change the flywheel and balancer on the same engine from a small weight to the heavier weight or vice versa without incurring problems? Or is it just so both are the same all that matters?
The engine itself is setup for either 28oz or 50oz imbalance ... the flywheel and harmonic balancer being matched does not matter if the imblance weight is incorrect.
So I have to use whatever came with the engine, right? How do you tell which is which on the balancer? I know the flexplate/flywheel will have a large weight.
My understanding is that 302s are balanced by the flywheel and not the balancer. When ordering my new balancer ,Iwas not asked what size of inbalance was needed. If you dont put the right weight flywheel on the engine, when you fire it up it will tear out the bearings real fast..hope this helps
Daydreamer your'e saying that only the flywheel matters,then? I'm not sure which balance was on this engine, not even sure if it's a 289 or 302, it had a manual flywheel on it and we're putting the AOD behind it. I know the flexplate is a 50 oz, and I have the balancer off of the same motor the flexplate came from. I guess I need to check the weight on the manual flywhell and get the same size on the flexplate.
Crankshafts are setup for either 28oz imbalance components or 50oz imbalance components ... the crank, damper and flywheel must ALL match ...
68-80 the 302 used the 28 oz imbalance 81 and later uses the 50 oz imbalance Like Dan said the balancer, crank and flywheel/flexplate must match
Courtesy of bmcdaniels, "You have to be sure of which crank you have, 28 oz and 50 oz have different counterweights. The crank, flywheel and damper have to all match. Check the crank casting numbers, 2M & 2MA are 28 oz imbalance, 2MAE is the 50 oz imbalance crank." I had the same problem a few months ago....hope this helps
Gentleman, thank you for your answers in getting me straight. I knew the basis but were unsure of the facts. Now I know if I can't find that 28 oz flexplate I took off a few years ago, I'll be in the market for one.
I just did this. Got the balancer from O'Reilly, and the 50 oz 157 tooth flywheel from e-bay. About $30 and $35 each. At O'Reilly, just ask for a later model 5.0 balancer, like 88 or so, maybe 93. Then you need to look on ebay for the 157 tooth (for the C4 "small bellhousing" 50 oz flexwheel.
Wow, another old thread. Just to continue the story, the engine turned out to be a 70 302. We didn't put the AOD behind it after all, it is going in the 82 pickup when I get time. My son sold the 68 pickup, and I ended up buying the engine back from him. It's going in the Fox body "Stang for a drag car when i get time and money to play with it....
balancer Dampner and flexplate/flywheel can be purchased separately. hell NAPA can probably get you both if your not real concerned about top shelf quality. If so just call Jejs or Summitt , both will have what you need in various price ranges.
