Well I bought a used balancer with the 50oz. imbalance, but the bolt pattern isnt the same as my pulley! Now I dont know what to do? My 302 is an 88. I used timing cover,water pump, pulleys and balancer from a 73 302 that I had. turns out the balancer was the wrong one for an 88 block. I'm hoping I can find a crank pulley with the four bolt pattern I need without having to change anything else. If I end up having to change everything because of this damn balancer I'm not going to be a happy guy. does anyone know if They made a crank pulley for the 50oz. balancer with only two belt grooves? does anyone have one?
I used my old 3-bolt pulley on a 4-bolt damper. The bolt circle and center hub hole are the same diameter. One of the bolt holes in the pulley will line up. Put a bolt in there, mark on the pulley where the other 3 holes need to be and drill 3 new holes in the pulley. Took all of about 10 minutes.
Thats what I did. and now the shakes like a MF! I'm guessing that it's becuase the flexplate I have was designed to work only with the 28oz. balancer. which means I probably didnt have to change it afterall. Oh well, when I do the t-5 swap the new balancer will work with that flywheel since it is out of an 80's mustang.
Some one correct me if I'm wrong but I believe that you have to have the rotating assembly that goes with that balance. Meaning if the rotating assembly came out with 28oz you can't simply change damper and flywheel to a 50oz and be good to go. Mind you the vibration might be less than what you're feeling now but it won't be right either.
That is my understanding. I talked with a friend of mine who has built dozens of 302's of all years and he indicated to me that there is a difference in the counterweight designs and hence the difference between early and late in balancers/flywheels.
Sounds to me like the flex plate needs to be changed to a 50 oz.'er. You HAVE to have the proper balancer and flexplate for that rotating assembly. Matching the flexplate and balancer is not what makes the rotating assembly be in balance. It requires matching the balancer and flexplate to the rotating assembly. Fred and Ward are correct.
Adam, I had the same problem as you. Here is what I did and it has worked without any problems, I took my old 4 belt crank pulley to my local speed/machine shop and ask them to cut off the front two pulley grooves and rebalance it for me. Costed $35.00 and as work like a charm, less weight for my motor to turn and look a lot better then that big ugly 4 groove pulley. Now don't try this at home with your sawall because it as to be cut down on a lay (forgot how to spell that). I hope this helps. Terry Gates AKA Bossmav
The balancer, flex plate and crank need to be from the same balance. I believe that the rods and pistons are interchangable. If you have an early crank you need the 28oz balancer and flex plate, if you have the late crank you need the 50 oz stuff. By early I mean (hope this is right) 1981 1/2 and before, late is somewhere in 1981 1/2 and later. Hope this helps.
Are there casting numbers or something to identify a "late" (50 oz.) 302 crank from an "early" (28 oz.) 302 crank? 302 cranks were cast w/ "2M" marking, maybe 50 oz. versions have their own identifier?
Ok so I was sleeping this morning at 5:15am when I made my post. First I didn't read the other posts right and then I couldn't remember how to spell (thanks Dennis) so let just pretend I never left a post at all. Coffee… I need coffee before I post! Have a good day everyone, looks like more rain on the mid-Atlanta for the weekend, no racing for me.
This is the wierd thing. I have had the 28oz. balancer and the flexplate that goes with it on the car since last summer. I felt a little vibration at 4000 rpms but I'm not sure thats even what it was from. when I put this new balancer(50oz.) on I got a hell of a vibration at 2000 rpms, probably because the flexplate is for the 28oz. My block and crank are 88. so I know that 50oz. is what I need. My question is: how come the 28oz. stuff seemed to be ok on the motor, with only minor vibrations at 4000 rpms?
There is no such thing as minor vibration from the rotating assembly. ANY vibration from the bottom end is a bad thing.
