91 Thunderbird 5.0L Sport manual T5 conversion, HELP! - TCCoA Forums
 
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post #1 of 18 (permalink) Old 07-28-2014, 07:38 AM Thread Starter
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91 Thunderbird 5.0L Sport manual T5 conversion, HELP!

Hello like minded individuals, thanks for having me!!

I'm going to try to keep the information grouped as nicely as I can, if there are any questions feel free to post them and I will get back with answers as soon as I can.

-History of the project so far

A number of years ago I found my first Bird on the side of the road for sale, long story short I always wanted a 5.0 and the Bird had everything I liked so I bought her. I believe they didn't make any 91 sports manual trans, only auto. I grabbed up a World Class T5 manual trans from an 89 3.8l super coupe along with the console to install into my 91. I got the pedal assembly and master cylinder from an early 90s ford ranger. I got the e brake from an 89 mustang and custom ran the brackets and cables. When the specs became available I had a custom drive shaft made.
After a few cases of beer and some hard work the bird was completed and ran great for the next few years without any problems (at least any pertaining to the drive train lol)

-Current problem with my Bird

(I am not an expert at all, everything I know is self taught, I am a great problem solver though and in the end I would put my money on the motor is out of balance, somehow)

Ok, so after years of driving it just fine after the conversion to manual, now when I go up to about 2.8k-3k RPMs to shift as I normally would (especially from 3rd to 4th, or 4th to 5th) as soon as I drop the clutch there is a !monsterous! vibration coming from under the hood. I do not feel this vibration at all in my steering wheel/column or in my pedals. The vibration is relative to speed I believe. So as I stated above I believe somehow the motor has become unbalanced. I understand that the 5.0 is externally balanced. Could someone go into more detail about what/how externally balanced consists of??

I have checked out my suspension just to be sure, nothing wrong there. I have also checked out my motor mounts and they are just fine as well. Just from opening the hood and looking at the motor while it is running, you can just tell that it is moving around too much, it even slowly rocks the car when you are just sitting in it idling.

Any help or insight would be awesome and thank you all in advance!!!

~Q~
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post #2 of 18 (permalink) Old 07-28-2014, 08:03 AM
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It might be time to change the Harmonic Balancer..

After so many miles when the Harmonic Balancer starts to fail..The rubber sandwiched between the insides of it starts separating..

If you're lucky enough to catch it before it breaks something..You could save yourself a lot of frustration, and $$$..

The symptoms you're exhibiting are what I'd expect from a Harmonic Balancer that's about to let loose..

Pioneer makes a quality Harmonic Balancer that won't break the bank..

Pioneer Harmonic Balancer 872010




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post #3 of 18 (permalink) Old 07-28-2014, 09:07 AM
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If you fabbed everything up using a pedal from a Ford Ranger, you certainly complicated your life! The SC pedal and master cylinder are a direct bolt-in swap. Also, the trans out of an SC is an M5R2, not a T5.

As far as your current problem, it sounds like either clutch chatter, or a bad motor mount. I would check the motor mounts first, as they are easier to change than the clutch. If they are good, next step would be to drop the trans and take a look at the clutch itself to see if it is worn out, or if there is glazing on the flywheel. Without knowing the specs on the ranger pedal and master cylinder, you may be having some kind of an issue with the clutch not disengaging fast enough causing chatter, so if it does wind up being an issue with the clutch, I would swap the pedal and master out for a tbird unit at the same time to avoid possibly burning up another clutch.

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post #4 of 18 (permalink) Old 07-28-2014, 04:21 PM
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I'm surprised you were able to get the Ranger stuff to work, I recently pulled the master out of one in order to get the clutch sensor for my SC pedal, and the thing of note was that that the pushrod between the pedal and master was VERY long(so long that the clutch sensor was actually mounted in between the arm and the master on the same pushrod). I have a hard time seeing how that would fit in a MN12

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post #5 of 18 (permalink) Old 07-28-2014, 05:17 PM
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Quote:
Originally Posted by QlovesHisTB View Post
... I understand that the 5.0 is externally balanced. Could someone go into more detail about what/how externally balanced consists of??...

~Q~
On older engines, the Harmonic Balancer would be the disk that has the timing marks on it. I don't remember if the timing marks were still on the Harmonic Balancer in 91 or not, but regardless, you'll find it behind the main pulley at the bottom center of the front of the engine, near where the oil pan meets the block, and behind the main pulley for your serpentine belt. Basically, it attaches to the end of your crankshaft and dampens the vibration in the engine, then the main pulley attaches to the front of it to drive your accessories.

Is this the answer you were looking for?

Tom "Buster" Glosser
1997 Cougar XR-7
Stock 3.8L
No mods... Yet.
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post #6 of 18 (permalink) Old 07-28-2014, 07:25 PM
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I don't recall what that bell housing looks like but is there any way you can look at the clutch disc while rotating the engine with a wrench? A buddy of mine who liked GTOs a lot back in the days we cruised a lot ('70s) once had a clutch disc partially disintegrate and we knew it was the disc, or thought we did .... but he babied it a few days until weekend came and we could get a new one in.
Near abouts 1/3 of the disc friction material was just "gone" .... leaving imbalance and chatter.

Edited .... I meant to say about a third was gone, was maybe 2/3 left. Not missing all over either, was missing about 120 degrees worth. The thin wavy metal was still there though.

A fine pair ... ... and whatever you do, Have a Safe Trip!

Last edited by CrystalPistol; 07-29-2014 at 08:11 PM.
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post #7 of 18 (permalink) Old 07-28-2014, 07:31 PM
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Near abouts 2/3 of the disc friction material was just "gone" .... leaving imbalance and chatter.
Eww...

Tom "Buster" Glosser
1997 Cougar XR-7
Stock 3.8L
No mods... Yet.
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post #8 of 18 (permalink) Old 07-29-2014, 07:36 AM Thread Starter
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Thank you all for the answers, and for the correction on the trans.

What is the proper way to test the harmonic balancer to ensure that it is in proper working order?

I wanted to know everyones thoughts since the trans is actually a M5R2 instead of a T5, would the flywheel I chose for it (from the 3.8L) be the correct weight or could that be an issue? What weight/tooth flywheel should be on there?(The one from the 3.8l or a manual 5.0 one?)

Also, could anyone give me the flywheel weight/tooth that would be in a natural 89-92 3.8L SC 5 speed?

Last edited by QlovesHisTB; 07-29-2014 at 08:13 AM.
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post #9 of 18 (permalink) Old 07-29-2014, 08:39 AM
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Quote:
Originally Posted by QlovesHisTB
What is the proper way to test the harmonic balancer to ensure that it is in proper working order?
Well..You won't be able to tell if it's bad by looking at it from just opening up your hood..

If the rubber is separating in the Balancer..You're going to have to get on your back, and crawl under the car..

You'll have to lift the front end so you can get a good look..

Take a good look between the Oil Pan and Harmonic Balancer..If you see any rubber protruding from the Balancer you'll have to replace the Balancer..

Like this:
Harmonic Balancer Fail.jpg

Compare that to a new Balancer:
atp-102032_hc.jpg

It wouldn't hurt to use an inspection mirror to have a look at the backside of the Balancer as well...Just to see if there's any missing rubber in it..






Rayo..

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1991 Ford Thunderbird Sport

"If you don't know where you're going..Any road will take you there." – George Harrison

Last edited by Rayo; 07-17-2017 at 01:14 PM. Reason: update pics..
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post #10 of 18 (permalink) Old 07-29-2014, 09:24 AM
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Quote:
Originally Posted by QlovesHisTB View Post
Thank you all for the answers, and for the correction on the trans.

What is the proper way to test the harmonic balancer to ensure that it is in proper working order?

I wanted to know everyones thoughts since the trans is actually a M5R2 instead of a T5, would the flywheel I chose for it (from the 3.8L) be the correct weight or could that be an issue? What weight/tooth flywheel should be on there?(The one from the 3.8l or a manual 5.0 one?)

Also, could anyone give me the flywheel weight/tooth that would be in a natural 89-92 3.8L SC 5 speed?
This might be your problem: an imbalance mismatch.

Your 5.0, unless you downgraded it to a crank from <1982, will need a 50oz imbalance flywheel.


* 1997 to 2000 mustangs are externally balanced 28oz.
* the later Mustang V6s from 2001- ’04 have zero balance. All mustang flywheels are fitted with 164-tooth starter gear rings.
* The very first 3.8L SCs from 1989 had a 28oz imbalance (and cast cranks, etc).
* SCs from 89.5 or 90 through end of production (95) were neutrally balanced.

I did the research for my swap. See this thread
http://forums.tccoa.com/showthread.php?t=142716

Since it sounds like you have found a starter+clutch+flywheel combination that works for you, you COULD rebalance the flywheel you've got for 50oz.

Or, you could go the 1995 F150 5.0 route.
In my situation, the only thing I needed to do was clearance the scattershield a little bit because there was a slight lip to the starter where it meets the shield that was a slightly different diameter on the F150 scattershield. The actual starter position is done with the mount bolts so the actual shape of the hole in the scattershield doesn't matter.

-g

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Last edited by S4gunn; 07-29-2014 at 09:37 AM.
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post #11 of 18 (permalink) Old 08-06-2014, 01:27 PM Thread Starter
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Originally Posted by Rayo View Post
Well..You won't be able to tell if it's bad by looking at it from just opening up your hood..

If the rubber is separating in the Balancer..You're going to have to get on your back, and crawl under the car..

You'll have to lift the front end so you can get a good look..

Take a good look between the Oil Pan and Harmonic Balancer..If you see any rubber protruding from the Balancer you'll have to replace the Balancer..

Like this:


Compare that to a new Balancer:


It wouldn't hurt to use an inspection mirror to have a look at the backside of the Balancer as well...Just to see if there's any missing rubber in it..





Rayo..

Thanks, it took me a number of days before I have had time to check it out. Sure enough, when I jacked it up and rolled under it to check out the Harmonic Balancer I instantly noticed that the rubber was protruding out everywhere. I'm going to fix it by the end of the week and I will let you all know if it took care of the problem or not, I'm sure it will. Thank you all so much for your answers!!!
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post #12 of 18 (permalink) Old 08-07-2014, 06:54 AM
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Quote:
Originally Posted by QlovesHisTB
Thanks, it took me a number of days before I have had time to check it out. Sure enough, when I jacked it up and rolled under it to check out the Harmonic Balancer I instantly noticed that the rubber was protruding out everywhere. I'm going to fix it by the end of the week and I will let you know if it took care of the problem or not, I'm sure it will. Thank you
No problemo..





Rayo..

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post #13 of 18 (permalink) Old 01-21-2019, 11:04 AM
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Note to self: Keep my sport an auto
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post #14 of 18 (permalink) Old 01-21-2019, 11:30 AM
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Note to self: Keep my sport an auto
Wrong, just get the right parts for the swap instead of trying to make ranger parts work, and know what trans you are working with before booting everything together. Done right, an M5R2 swap is the single best mod you can do to a 5.0 MN12.

-91 Cougar LS, coming soon, complete overhaul with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
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post #15 of 18 (permalink) Old 01-21-2019, 11:43 AM
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Wrong, just get the right parts for the swap instead of trying to make ranger parts work, and know what trans you are working with before booting everything together. Done right, an M5R2 swap is the single best mod you can do to a 5.0 MN12.
Tbh, that's something I've been wanting to do for a while, but idk if I'll have the time. There's a 93 sc manual sitting in a junkyard near my house that I want to rip the transmission out of.
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post #16 of 18 (permalink) Old 01-21-2019, 12:59 PM
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Tbh, that's something I've been wanting to do for a while, but idk if I'll have the time. There's a 93 sc manual sitting in a junkyard near my house that I want to rip the transmission out of.
Your profile says youre 18 years old … you have ALL the time in the world. LOL
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post #17 of 18 (permalink) Old 01-21-2019, 04:10 PM
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Your profile says youre 18 years old … you have ALL the time in the world. LOL
That is correct, but as of yesterday it looks like I'll be spending the rest of my life in another state, beginning this summer. I have 3 cars to my name and am about to get a 4th... Wherever I go, I can't take them all with me, and I think it's the sport that's gonna get cut. Maybe someday I'll have the time to do it, but it's already January and I still don't have the catalytic converters in my car that I've been meaning to do for like a month.
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post #18 of 18 (permalink) Old 01-21-2019, 04:27 PM
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That is correct, but as of yesterday it looks like I'll be spending the rest of my life in another state, beginning this summer. I have 3 cars to my name and am about to get a 4th... Wherever I go, I can't take them all with me, and I think it's the sport that's gonna get cut. Maybe someday I'll have the time to do it, but it's already January and I still don't have the catalytic converters in my car that I've been meaning to do for like a month.
When I was your age, I was working two jobs, going to college and still building cars in my spare time. With only about 5 hours of sleep - its no different than where I am now.

The only way youre spending the rest of your life in another state is if you are going away to a maximum security facility, or by choice. Id love to spend the rest of my life here in California, but I cant say that for certain. What else could you possibly own that would make a Tbird with only 55k miles an expendable vehicle ?
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