I'm reinstalling the original motor into my '95 GT after having my 347 "fun". The orginal motor has been on a engine stang covered (bagged) for the last six years. Now that I've put the motor back in, I have a mystery vibration.
When the motor was pulled I felt it was fine, only 100K miles, and smooth running. The original balancer did die and was replaced with a 50oz Romac balancer. When putting the motor back in, I replaced the flywheel (50oz) with a cheap parts store brand, and installed a new Ford Racing HD clutch. Before, installing the trans I did notice the input shaft had a bit of "wiggle", but I hadn't noticed any significant tranny issues prior. When the vibration started I suspected the cheap flywheel and have since replaced it with a Ford Racing unit. However, when I was reassembling the car, I ran the car with out the tranny connected and experienced none, to very minimal vibration. I have since installed the transmission and now have this vibration I can't track down. Last night I took the serpentine belt off and ran the car a few minutes and the vibration was still there. This weekend I'll be pulling the flywheel and balancer to have them spin balanced/checked at the machine shop.
Not sure what else to check. I do have poly motor mounts, but I don't think rubber would mask this. My 347 was on these poly mounts, and it did not feel like this.
How much play is the input shaft allowed to have? I saw someone (other site) mentioned the pilot bearing might not be holding the input shaft correctly, how else do you check this? I figured if the trans goes in and bolts up, you're good!?
Just listening to the car, it sounds...good, surprisingly good. No knocking, very smooth sounding. I just have this mystery vibration.
Ok, well this is a rare one, but sometimes there is a slight difference in weights between the pressure plate bolts. I've had to take them out and weigh them. Ended up having one that was a hair off, and had to shave it a little.