Engine Vibration

[frank p]

I picked up a 1987 302 ford engine with supposedly 25-30 thousand miles which an older gentleman had in his 56 ford show truck (very nice truck!) he had a muscle motor built for his truck and no longer needed the old 302. I stripped the motor down to a short block and added my own stuff. I put on set of match ported and slightly polished heads from my old motor which I had rebuilt prior to putting on the new motor, aluminum intake, holly 600 cfm carb, new isky cam and lifters, new double roller gears and chain, new 50 oz harmonic dampner, new 50 oz flywheel with new pressure plate, clutch, throwout bearing and shop rebuilt T-5 trans and my HEI distributor from my old motor with new cap, plugs and plug wires. I finally got it all assembled and stuffed in my 62 falcon but after getting it to fire up it has a bad vibration that gets worse with more RPM. When I previously had the motor down to a short block it was on an engine stand and I was able to spin the rotating assembly and move the pistons up and down with no problems and everything looked good. I haven't been able to run it long enough to break in the cam and don't know what I possibly missed. There are no rattles or thumps coming from the motor. Any suggestions

 

[HOT40ROD]

Are you sure it was a 1987 Motor. It sound like a balance issue. Are the old flywheel and harmonic balancer 50 oz. If you have the old stuff get the part numbers off of it and I will check it for you to see if 28 or 50 oz.

Do you know if the motor was ever apart before.

 

[Sniper]

I would have to agree, sounds like a balance problem, one that was likely induced with the new flywheel and or harmonic balancer. The stamped part # of the block should be E7NN-****** if it's a 87. With E being the 80's and 7 being the year of that decade, the NN is part of the part# prefix. (I've seen AA and BB, but most times it's NN.) A dash and the following numbers are the actual part number given to that piece, the first two are the year. Ford used that system across the board, cars, trucks, tractors and ag equipment and what ever else they touched. C was for the 60's, D 70's, E 80's, F 90's and so on. A stamped part number should be the current part# giving you the correct year. Where as....a casting part number will, or could be the original part number when the piece first came online. Yes I know, a bit confusing. If the engine has been produce for a number of years, and if no major changes, it would keep the same casting number with the same original prefix. But as the engines were produced over the years, the stamped part# prefix could, and quite often was updated to the current year with the remaining part# staying as it always was. There...clear as mud!! Find the stamped, machined pad on the block, and there will likely be both a serial and part#. From that part# you can find the engine year.

 

[donsrods]

The problem with buying someone elses stuff is that you have no idea what modifications he might have made over time. For example, the engine in my 27 is a 1990 Mustang 5.0 that should by it's year be a 50 oz imbalance. But I have a Scat stroker in it, and that is a 28 oz imbalance setup. If yours is an 87 it should be 50 oz, but maybe he or someone else put an earlier crank in there. Maybe he had a machine shop modify it for some reason.

You should be able to pull some numbers off of the crank to see what year it is from. 81 down is 28 oz, 82 up is 50 oz. Can you call the PO and ask him what it is?

Don

 

[Screamin' Metal]

What Don said. Also, make sure your flywheel is for that motor, the same with the balancer. Make sure there aren't any gyrations going on with the balancer or flywheel. Make sure all the RODS look the same. Look at the crank and see if you see any drilled holes on the counterweights. Someone might've messed up at the balanceing machine....Might even have a crack thru one of the mains....fixing to loose the crank. CHECK EVERYTHING!
If no satisfaction....I'd look at the Torque converter, sometimes they can throw a weight off.
Take your time, go slow, pay attention to details....don't overlook anything. While its outta balance like that, don't put much rpm's to it....if its shaking that bad, its probable screwed the bearings up by now! They are made of a very soft babbit/tin facing on a metal shell backing....
I'd hate to see you loose a rod, or break a crank. Thats a sound that totally makes me sick when I hear it. I can tell the sound just a few seconds before it happens. If I'm at the key....I can usually keep it from scraping the motor....