I installed an '87 or so 302 roller engine in my '72 Maverick and started it for the first time a couple of weeks ago. With carb and timing adjusted, it runs smoothly at idle but above idle it shakes the car pretty severely. Engine has the 351 firing order and plug wires are on correctly. I'm sure its a balance issue, not a misfire. I've seen lots of engines with a misfire and this is quite different. The used roller engine came with harmonic balancer and 164 tooth flex plate. Comparing them to the 28 oz '72 parts I believe they are 50 oz parts. I bought a new 50 oz balancer, new 50 oz 157 tooth flex plate (to fit my bell housing) off ebay, and new torque converter. I suspect the ebay flex plate but am looking for advice on how to find the problem. Seems to me the TQ would be the next most likely defective part. The transmission is ready to come out and my buddy and I will remove it tomorrow. I have my old, servicable TQ and the balancer that came with the roller engine and could try swapping parts and rreassembing to test. Hope I don't have to pull the harmonic balancer. Might call the machine shop that did the work on the roller block to see if they can test the balance on the balancer, flex plate and TQ. Any suggestions on how to go about identifying the problem?
I put an '86 302 in my car, and had the same problem. The flywheel I used was a Fidanza, 50oz, and the balancer that came on the engine, a 50oz. The thing shook really bad. After changing the balancer, plugs, and anything that could be a problem, I had the flywheel replaced with a stock 50oz flywheel. Problem was cured. Your flywheel might be out of balance, even if it is the right one. Also, might be the clutch, so check that out also.
Its an automatic transmission. I suspect the ebay flex plate but am hoping someone has a trick for testing them without reassembling everything. If I had a big bell housing I'd install the 50 oz 164 tooth flex plate that came with the roller engine, the big bell and starter and run the engine without the tranny. Think it would stay put with no load at fast idle. Or, maybe the machine shop can test the flex plate balance? I'll give them a call tomorrow. Thanks for the reply.
Problem Resolved I did call the machine shop and asked if they could test the balance on the flexplate or TC. Answer: "no". Only thing they could do is balance the entire rotating assembly with the engine torn down. They referred me to a guy at a local tranmission parts place but he couldn't hep either. I determined that the new "50 oz" flexplate was really a 28 oz flexplate. Might do a thread in the "tools" section to explain how. Anyway, I ordered another 50 oz flexplate from Summit and installed it today with help form a buddy. Shake is gone. Anyone need a 28 oz SFI flexplate? I have one I don't need.
