Flexplate Issues, please help!
Flexplate Issues, please help! Alright, Im lost, so dump you knowledge here!
The motor is a 383 Stroker, runs fine but vibrates like hell when you rev it in neutral, when you get on it in any gear, or when you coast. The transmission was just freshly rebuilt. I had my friend change out the Flexplate, as we noticed that it was a stock piece with a heavy weight on one side. We were guessing that the motor was balanced, and the weight on the flexplate was the source of the vibration. We put a brand new TCI flexplate on it, part number 399174 which is supposed to be neutral balanced. For some reason, this flexplate has the exact same weight on it that the stock one had. He put it on the car and it still vibrates like crazy, the same as it always has.
Just some background info, this car has vibrated like this ever since the motor was put in by the previous owner. Everything else is in order, no misfires, crank pulley is in good shape and hasn't spun. everything that we see points to a balance issue with the motor, but the new FP didnt cure anything.
Any Ideas? Should the TCI 399174 actually HAVE a weight spot welded onto it? It has to be a 1 piece RMS, since this FP bolted right up to it.
I was actually expecting the TCI part to not have a weight on it, but thats how it came. the part number was correct on the box AND on the part.
The motor is a 383 Stroker, runs fine but vibrates like hell when you rev it in neutral, when you get on it in any gear, or when you coast. The transmission was just freshly rebuilt. I had my friend change out the Flexplate, as we noticed that it was a stock piece with a heavy weight on one side. We were guessing that the motor was balanced, and the weight on the flexplate was the source of the vibration. We put a brand new TCI flexplate on it, part number 399174 which is supposed to be neutral balanced. For some reason, this flexplate has the exact same weight on it that the stock one had. He put it on the car and it still vibrates like crazy, the same as it always has.
Just some background info, this car has vibrated like this ever since the motor was put in by the previous owner. Everything else is in order, no misfires, crank pulley is in good shape and hasn't spun. everything that we see points to a balance issue with the motor, but the new FP didnt cure anything.
Any Ideas? Should the TCI 399174 actually HAVE a weight spot welded onto it? It has to be a 1 piece RMS, since this FP bolted right up to it.
I was actually expecting the TCI part to not have a weight on it, but thats how it came. the part number was correct on the box AND on the part.
You have a balance mismatch issue, that motor should have been internally balanced and no weight needed on the FP anymore.. Without pulling the crank and Rods and FP out and having balance checked ..you may never know... 
My TCI FP has no weights.. My 383 Motor is internally balanced...
Take the stock piece and remove the weight to see if it changes?
My TCI FP has no weights.. My 383 Motor is internally balanced...
Take the stock piece and remove the weight to see if it changes?
You have a balance mismatch issue, that motor should have been internally balanced and no weight needed on the FP anymore.. Without pulling the crank and Rods and FP out and having balance checked ..you may never know...
My TCI FP has no weights.. My 383 Motor is internally balanced...
Take the stock piece and remove the weight to see if it changes?
My TCI FP has no weights.. My 383 Motor is internally balanced...
Take the stock piece and remove the weight to see if it changes?
I got the FP from a friend for free, and he had ordered it from Summit. I called them up just to see what they were going to say about it. The rep told me that the 399174 is NOT suposed to have a weight on it.
So it appears that since the part number on the box AND the part number printed on the part itself are 399174...... TCI mislabeled this Flex Plate. It has a big honkin weight just like the stock FP does. Thats why my vibration is still there. Oh well. This car has been ran for 2 years without the proper flex plate on it, vibrating all the way. I'm not swapping it again this year, since the car will be n storage in a few weeks. Its been ran on the street a LOT, with at least 4 track days thrown in for good measure. Nothing seems to be out of place yet
My oil pressure looks good, and the last oil filter we cut apart looked fine with no metal particles in it. I think it will be alright for now. I hope...
Teching In
Joined: Feb 2010
Posts: 42
Likes: 0
From: Bartlett, Il
The balance weight is held onto the flexplate with 4 spot welds---you can drill them out from the front by removing the starter or oil filter---you will need probably a short 1/4 bit and an off set or 90 * drill
