Update on my motor vibration on my newly purchased fastback (pulled trans)

DarkoStoj

Founding Member
Sep 4, 2002
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39
Detroit
So I just got done pulling the trans to check everything out. The pressure plate looked good, it was the 3 finger style type, and it looked almost new.

The flywheel had three numbers cast into it.

D7TE-6380-GA
6J6
and 12

The flywheel also seems like it is in great shape. Here are some pics

351c%20front.JPG

351c%20back.JPG

351c%20%20number.JPG


Can anybody identify this flywheel whether it is the right one to be using with this motor? My motor is a 1970, and the date code on the flywheel is a 1977. I think the flywheel I pulled is a 28oz, because when I compared it to a 50oz flywheel I had sitting around (out of a fox) I could tell the imbalance cast into the 50oz flywheel was much larger then the one I pulled.

Here is a picture I took of a 50oz flywheel I had laying around.

50oz%20flywheel.JPG


Here is a picture of the clutch disc and pressure plate. They seem pretty stout. Does anyone know if I should have problems with the clutch slipping with this pressure plate and disc?

clutch%20disk.JPG

pressure%20plate%20back.JPG

pressure%20plate%20front.JPG


Now the throwout bearing was absolutely TRASHED. I mean there is about a 1/2" of slop in it. Would this have caused the vibration I felt, or was the throwout bearing wearing down a byproduct of the vibration from the motor?



and stangnet, i'm lost without you :)
 
krash kendall said:
I can't answer all your other questions, but by any chance is the pilot bearing installed? Is there any play on the input shaft of the tranny?
Yes, there is a pilot bearing in the crank (not bushing)

and I measured the play at the tip of the input shaft with a dial indicator and it was at ~.05
 
I don't know what the tolerances are for that trans, but in my line of work (I run a CNC machine shop) 0.050 is huge! I wouldn't want to see any of my equipment spinning at two to four grand with that kind of play.

Does the pilot bearing fit nicely on the end of the shaft or is it way oversized now? Can you get it out?
 
krash kendall said:
I don't know what the tolerances are for that trans, but in my line of work (I run a CNC machine shop) 0.050 is huge! I wouldn't want to see any of my equipment spinning at two to four grand with that kind of play.

Does the pilot bearing fit nicely on the end of the shaft or is it way oversized now? Can you get it out?
well thats the play I get while measuring at the tip of the input shaft. Its about 12" away from the bearing...if I put the dial indicator closer I would have got a smaller reading.

I'm not sure if that makes a difference or not though.

I havent checked the condition of the pilot bearing, how do I pull it without damaging it? Do I use the grease and a peice of wood?(never had luck with that before)
 
If it's a bearing I don't really think the grease will work, but it is worth a shot. For the price of them and the fact that you have everthing out anyway, changing it may be a good idea so I wouldn't worry about damaging it. I've changed piles of bushings, but the only vehicle I had with bearing (jeep Renegade) I didn't change because I was pulling the tranny out for a different reason than vibration.

I think since your throwout bearing is shot you may be best to get a clutch kit with everything in it and get the flywheel surfaced.

Either the balancer went and damaged the clutch assembly, resulting in vibration after replacing the balancer, or the clutch went first and cooked your balancer....one would hope that's all.
 
also I've been talking to ronstang, and he thinks that the lakewood bellhousing could be out of misalignment. I'm going to make a jig tommorow and measure how the bellhousing is centered, call the ford dealership to check what the flywheel came out of, and get a new throwout bearing.

is 28oz the right imbalance for a 351 cleveland?
 
From what I understand 302s from 81 to present used 50oz 157 tooth flywheels. Before that its 164 tooth and 28oz. You can get 157 tooth 28oz flywheels though, as that is what I have for my t-5 conversion. This is all 302s though. I have no idea on the cleveland. Do a google search and see what you come up with.
 
The throwout bearing shouldn't have anything to do with the vibration but, of course, it needs to be replaced. Since you have the bellhousing off, check the crank for endplay. You'll have to put the flywheel back on for something to grab on to but worth a try.

Even though you have a 28oz harmonic balancer and 28 oz flywheel, don't they have to match the crank? Is it possible for the crank to be from a later 302/5.0 and 'balanced' for 50oz? Experts? Will have to pull the pan to check that one, I guess.
 
I measured the bellhousing, and the center is off .025"

Could this have caused a lot of the vibration?

I'm gonna get a new throwout bearing and pilot bearing, and offset dowels for the bellhousing, put it all together, and pray I guess.

If none of this fixed the vibe I'm out of ideas.
 
DarkoStoj said:
I measured the bellhousing, and the center is off .025"

Could this have caused a lot of the vibration?

I'm gonna get a new throwout bearing and pilot bearing, and offset dowels for the bellhousing, put it all together, and pray I guess.

If none of this fixed the vibe I'm out of ideas.

Refer to my post in your previous thread, if you have an aftermarket bellhousing, it must be centered/aligned within 3thousands of an inch. Lakewood bellhousings are notoriously off center. The ones from Mcleod are much better. I had the bellhousing aligned, then had some "nuts"(for lack of a better word) tig welded on the housing to prevent any shift in the offset dowels should I ever take it off again. Good luck, I hope you find the problem, you have been working hard at it.
 
.025 is ALOT! If you're using a toploader, .014 is the most off center tolerable, per the Ford Shop manual. If running a Tremec of any sort, .005 is the most tolerable. As 4MM stated, .003 is what you can be looking for.

Keep us posted.
 
gjz30075 said:
Even though you have a 28oz harmonic balancer and 28 oz flywheel, don't they have to match the crank? Is it possible for the crank to be from a later 302/5.0 and 'balanced' for 50oz? Experts? Will have to pull the pan to check that one, I guess.

Not trying to be a jerk, its a 351C.

And to answer the question, 351C all came from the factory with 28oz imbalance. Unless it was rebuilt with a crank balanced to 50 or 0 from a shop it should be 28.
 
they make offset dowel pins to correct the allignment. It is in the literature that came with the bellhousing origionally. Lakewood also recommends checking for correct alignment on initial install.Too bad that didn't happen before you got the car. Good luck.
 
about the throw out bearing, it was probably not releasing completely, causing it to wear excessively. Look at the piviot point in the bellhousing and the clutch fork, making sure there are no signs of unusual wear. Just for info purposes, the pressure plate is known as the Long type, used in all of the earlier fords that I have seen, Chevy and the late model Fords use the diaphram type. Also make sure the return spring is pulling the Zbar all the way back to fully disengage the throwout bearing.Also...look at the bushing on the Motor and the framerail to make sure there is no play in these. The nylon inserts are cheep....about the only cheep thing in this fix except maybe the pilot bushing...
 
so I initially measured the run out wrong, and it was fine with the stock dowels

Now I got it all back together and getting that toploader up there myself was a HEAVY sob....good thing I'm a beefcake so it was easy.

almost ALL of the vibrations are gone. I changed the roller pilot bearing, and the throwout bearing, then i just reassembled everything

Now i have some vibes left, but they are a little different. Say I'm going 70mph I get the vibes at around 3500rpm, then if I let off the gas and let it slow down they get a lot worse.

I ended up changing the harmonic balancer, pilot bearing, and throwout bearing. I'm still not really sure what was causing the vibration, and still am not sure whats causing the little that I have left.
 
DarkoStoj said:
so I initially measured the run out wrong, and it was fine with the stock dowels

Now I got it all back together and getting that toploader up there myself was a HEAVY sob....good thing I'm a beefcake so it was easy.

almost ALL of the vibrations are gone. I changed the roller pilot bearing, and the throwout bearing, then i just reassembled everything

Now i have some vibes left, but they are a little different. Say I'm going 70mph I get the vibes at around 3500rpm, then if I let off the gas and let it slow down they get a lot worse.

I ended up changing the harmonic balancer, pilot bearing, and throwout bearing. I'm still not really sure what was causing the vibration, and still am not sure whats causing the little that I have left.

i'm still betting on a driveshaft balance issue. man dude just spend the money and get the shaft balanced it's well worth the 50 bucks or so they'll charge you for the balance job. i presonally will never change another u-joint myself after having the shaft in my cougar balanced, man what a world of difference even though i had never had a vibe problem before the balance job. i'm going to have to replace the u-joints in my DD cherokee soon and i'll be taking the shaft down to the local driveshaft shop for them to install the joints and balance the shaft afterwards.

just my 2 cents, bro, even if it doesn't fix all of your vibe problem you'll still be glad you did it and i'd still bet money that the shaft needs it anyway