Brand new engine installed. 2002 4.7 automatic. It runs great no leaks all plugs and coils check out. It has a bad out of balance feeling at 1000-1400 rpm in neutral or drive. Removed fan and clutch and disconnected torque converter to eliminate possible causes. Still does it. Could it be an out of balance crank or could I have possibly put the flex plate on wrong.
Did you try to run the engine with the fan belt off?
Run the engine with the fan drive belts off and see if the vibration goes away. You can run the engine for a very short time with out overheating the engine.
You can try to spin the fly wheel one bolt hole at a time. This is a pain but you can reposition the counter weight every time you move the flywheel one bolt hole. It may improve the condition or it could get worse.
Sometimes when you are moving the flywheel you also move the counter weight position, this will put the counter weight in a different position with each bolt hole position. With a new engine it may help compensate for the vibration.
You can try the easy way and swap the flywheel with a known good one to see if the vibration goes away.
It's a lot of work but you can try these suggestions to see if they improve the vibration.
You still may have an out of balance condition with the engine itself if these suggestions don't work.
If you can keep us informed on your progress it can help us help you diagnosis the problem further.
Found out from a friend at the dealership that the flywheel can only go on one way. so that meant i didn't have to worry about that. going to replace aftermarket harmonic with one from the dealership. Will try without the belt. never thought to try that.
How much of the engine is factory new?
What parts did you swap over to the new engine?
If you used the old harmonic balancer on the new engine and you didn't have a vibration before then chances are it is not the balancer.
If you covered the basics like the ones you listed and still have the balance problem in the engine then you should consider bringing it to the dealer.
If you bought the engine new from the dealer or factory then this would be something that would be under their warranty.
It may be worth it to pay the hour diagnostic fee to find out that it is their problem and not yours. You didn't build the engine, they did.
This is just a suggestion, maybe you and the factory can work out something like let them pay a percentage of the bill because you didn't build the engine.
If you can keep us informed on your progress.