Wrong flywheel put on the engine?? The early 302's are 28oz. imbalance, the late model is 50oz. If the trans shop put a 50oz flywheel on an early motor, it'll shake like crazy and you'll drive yourself nuts trying to find it.

Or the opposite, you have a late model 302 with the early flywheel. Same result.

 

Well the engine block is from 86 thunderbird. and i had e7 heads on it. When i took the motor in to get rebuilt they didnt specify that they were putting in a 50 oz wheel.

So im not sure, and the replacement was for 68 mustang so there is a good chance that it is a 28oz flywheel

 

There you go, that's the problem. Wrong flywheel!

 

I will do that!

 

That or your u joints or driveshaft is out of whack. Did you check you engine/tranny mounts?

 

You might reread the original message where it says the vibration is there with the transmission disconnected and out of the car. Just running the motor alone and it vibrates means it has an imbalance problem. The combination of the late model motor with the early C4 and likely the early C4 Flywheel has caused the problem.

 

question! So the shop is gonna switch out the flywheel on monday back to the original one. What my question is if the motor was vibrating a little with the original flywheel thats okay right? I mean without connecting the transmission to the bell housing and drive shaft im sure that would cause the motor to shake a little right? I mean it is a 302 with a bigger than stock cam in it. If we just run the motor, there should be a little shaking in the back by the bell housing no? Im sure that connecting the transmission adds a little more stability to the car.

 

I'm far from an expert, but it would make sense that there would be some vibration with no trans hooked up. I remember your posts from about a year ago when you were dealing with finding a new motor, so I wish you only the best in getting this vibration issue resolved.

 

i am assuming you have the correct balancer for that motor.

if not....and the motor is supposed to have a 50oz balancer, it needs to have a 50oz balancer and matching flexplate. if the motor requires a 28oz balancer, then the motor needs a 28oz balancer and a 28oz flexplate.

 

So here's the scoop! I got the original flywheel put back on. Now I realize that when the mechanic attempted to put a new balancer on there the motor had the 28 oz flywheel, which was incorrect. The motor is still vibrating, I even put some new motor mounts in. Could it be that it needs a new balancer. There's a good chance the mechanic tried a 28 oz flywheel anyways. I don't know what else it could be

 

If I follow your sequence of events:

You changed from 50 oz to 28 oz flywheel (while retaining the 50 oz balancer)
You changed from 50 oz to 28 oz balancer (which should have balanced things out)
You changed back to a 50 oz flywheel (which unbalanced things again)

You had a vibration problem with the original 50 oz setup and it appears that you had a vibration problem with the 28 oz setup. I would put my original parts back on and look elsewhere for the problem.

 

A big cam causes a lop when idling but it smooths out when you come off idle. I agree with everyone here. Straighten out the balancer and flywheel. I'm assuming the engine runs ok, if not make sure the plug wires are in the right order. that can feel like a bad vibration.

 

Yea u guys got it right. It currently has the original flywheel and balancer on it. My mechanic has an idea that when the tranny was shifting hard, and off balance torque converter and bad flywheel that it could have caused the balancer to slip. And I am getting new spark plug wires. Does that theory sound possible?

 

of course it calms down when the car is warm but it does have the vibration and gets worse when accelerating.

Sounds like a cold hole, like either a misfiring plug or a vacuum leak. You say you're getting new wires, that's good. Check the hole ignition system to make sure you're getting spark in every cylinder. I had a mystery vibration like this for a while. Turned out one of the spark plugs was shorting to the header. Could only see it at night and I really just stumbled across it by accident. Got a great video. See it here: Shorting plug wire on Ford 289 - YouTube A new set of FRPP plug wires and blue boot insulators, nary a problem since.

Hope this helps.
JACK

 

Well i got new plug wires on. Still vibrates... Im really frustrated. The things iv'e done on this car, its been a huge can of worms I get it going and then this.

and now theres a new problem! my car was randomly rumbling right around the flywheel torque converter. It was weird it happened for the first time today, it wasnt in like wave like timing but it just would do it randomly. I put the car into gear and it stopped. put it in neutral and it began, I put it back into drive and then back into neutral and it stopped. I hate it my car was working till I took it into the transmission shop, they had my car for a little over a month and now I have this new problem that no one can figure out. its so frustrating. heres a laydown to what happened.

1) tranny was acting up, took it in to the shop to get a rebuild.
2) get car back running like crap, we figured faulty torque converter. Get car back with original torque converter rebuilt, rumbles but not as bad.
3) tranny shop thought it was the flywheel, that they noticed some type of back and forth movement with the wheel.
4) they put the 28oz flywheel in there. So I had my 86 302 with a 28oz flywheel and the 50oz balancer.
5) my mechanic tried a new balancer, but I believe he tried a 28oz balancer. which means the 86 motor had the 28oz flywheel and then a 28 oz flywheel. But doesnt it have to match the crank? took the 28 oz balancer off and put on the original one.
7) got the original flywheel put back on. so now I have a 50oz wheel and 50oz balancer.

His theory was that my balancer went bad but when he changed it out he said there wasnt much of a difference. But the motor did have the wrong flywheel in, So I dont know if that means that I still need a new balancer.

PLEASE HELP!

 

You said the transmission shop noticed for and aft movement of the flywheel so they changed it, for and aft movement is crank thrust, is the thrust bearing worn out letting the crank rub on the block?

 

after the first torque converter they, put the car on a lift and pulled the driveshaft and tranny and ran the car. They pointed out that the engine was vibrating, by itself without the tranny hooked up. (trying to get the blame off of them and say hey look the engine still shakes without the tranny, so it cant be the tranny). thats when they looked at the flywheel and said it looks like it has some wobble, so they put a new one on but it was the 28oz. and didnt do anything to fix the vibration.

How would I know if its the thrust bearing?

 

how can I check to see if the thrust bearing failed? Because i did notice slight flywheel wobble. Also how do you fix this and how much will this cost?!

 

To check the thrust bearing you would need to put a dial indicator on the crank and pry it for and aft to check the movement, dont pry on the balancer outer ring it will destroy it.

 

Ok, i misunderstood what you were saying, wobble may not be the thrust bearing, if the crank moves for and aft that would be a loose thrust bearing. I think your problem lies in the flex plat and the balacer if it isa 86 302 you need 50 oz for both.

 

Well it has the original flywheel and balancer on it now. But I think the balancer may be wrong. But I feel I should check the thrust bearing as well. any other ideas? I hope its the balancer. the motor is like a year old, and they did install the torque converter in wrong the first time or whatever, I wouldnt be surprised if it is the thrust bearing

 

maybe the orginal balancer is bad? pics always help out.. if its the orginal balancer it very well could be... when i pu tin a 83 302 once i found the imbalance thing the same way as you. but it was the wrong flywheel.. a new one fixed the issue... have you tried a compresson test yet?? just because the engine is new doesnt mean anything.. i would say as long as your cyclinerds are within 10-15% of eachother and over 130 psi, you could rule that out...

 

Okay will do! And I will take some pics

 

Sorry to hear about your troubles. I had a similar issue in my first '67 coupe. The 302 motor was installed with the wrong flywheel and vibrated so bad it made your teeth chatter. I didn't figure out the problem until a year later when I had the motor out for a rebuild. Fortunately for me, the problem was obvious.

So, this has been bounced around a bit, so here's my comments/advice.

>Where did the motor come from? Was it rebuilt? Are you sure of what year the crank/rods are from?
>As said, before: make 100% sure that your balancer and flywheel(flex-plate) both batch the motor you have.
>Make sure the balance weight on your flex plates are intact. They are welded on and can break off.
>You replaced the motor and tranny mounts with new ones?
>Make sure you have the firing order correct. Some of the 302HO motors have a diferent firing order. (probably not your issue, but you never know)

 

Time out. Take it to a different shop. You're dealing with two shops that can't find the problem and are blaming the other shop while you fund their pissing war. You need a 50 oz balancer and flywheel period. Sure it'll run smoother when you have a 50 oz balancer and a 28 oz flywheel when compared to running a 28 balancer and flywheel but it will still vibrate, just less. I had a vibration that was driving me nuts. I thought for sure it was the engine because the engine was rebuilt by a shop that forgot to refill the crankcase with oil after a oil change with the PO. So I swappwd motors with a known smooth running but tired engine. It wasn't until I swapped in a 4 speed that I discoverwd the bushing in the front pump was shot as well as the snout on the converter was worn.

I'm an electrician and I know it's very, very easy to assume something is ok when it's not and go crazy looking for the problem. It's that time to step back and let some one who is not predujus take over.

 

I got the motor rebuilt a year ago from a very good machine shop in town. I had the motor tested and the mechanic told me it was very very healthy. This was of course like 6 months ago.

Yea the tranny shop has no idea what there doing, and I guess the motor shop might not want to take responsibility because that means that they need to fix it haha. I will say though, no problem till I got it back from the tranny shop.

I spoke to my mechanic and he looked at my balancer and told me that it wasn't the problem that it looks very good. he also said that it wasn't a crank thrust bearing. He said that if I had a thrust bearing causing that much vibration it would absolutly ruin the motor.

I'm thinking about taking it to someone fresh. My question is to I tell them the whole story? Or just say my car has a vibration, and I don't know why?

But yes it has new motor mounts I put in like a week ago and it got a new granny mount put in when the tranny got rebuilt.

 

I don't think you have stated clearly what type of balancer you have on there? Are you sure it is a 50oz part?

I know you said you had the motor rebuilt. Where did the motor come from? Is that the same balancer that 'came' with the motor?

 

The motor is out of an 86 Thunderbird. It was in the car when I bought it. When I got the motor rebuilt I'm pretty sure they put a new one on. When I spoke to the shop they knew about the 28oz to 50oz change that ford did. and they told me that they had 50oz flywheel and balancer on there. And as stated it was fine till the tranny shop got there hands on it, it has the fly wheel and balancer that I had on it when it was working fine till then. And I got off the phone with the motor shop and he said it is also not the thrust bearing.

I know when I was looking at the flywheel, it had a weight welded into it, so I doubt it fell off unless its suppose to have 2 weights on it.