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Technical => Engine Swapping => Topic started by: SR71TC on September 30, 2009, 02:47:36 PM

Title: 1991 3.8 mn12 tbird engine swap question
Post by: SR71TC on September 30, 2009, 02:47:36 PM
I have a 1991 3.8 tbird that has a blown engine and a slipping tranny.  Next, I have a complete 5.0 and T5 that I want to install in said tbird.  How big of a head ache is it to do this swap? Any leads to some good web sites would be very helpful. In the meantime I'll keep on searching, thanks in advance.

~Jason
Title: 1991 3.8 mn12 tbird engine swap question
Post by: DVP on September 30, 2009, 04:20:21 PM
Shouldnt be too much harder than a Fox swap since 5.0 was an option in the MN12.

But why a rot box?
Title: 1991 3.8 mn12 tbird engine swap question
Post by: SR71TC on September 30, 2009, 04:23:23 PM
Rot box? hahahaha....is that a term for a mn12? If it is, well there is no rust on this one, plus it was donated to me.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: DVP on September 30, 2009, 04:52:28 PM
Texas.... Lucky
Title: 1991 3.8 mn12 tbird engine swap question
Post by: RoyLPita on September 30, 2009, 07:44:48 PM
The 5.0 for the MN12 uses a lower intake manifold like the 94-95 Mustang GT.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: Sick88Tbird on September 30, 2009, 08:19:53 PM
MN-12 uses a shorter upper plenum...a standard HO upper will bolt on and you could make it work with the proper TB adapter available from almost every aftermarket company...however, hood clearance may very well be an issue.

-Don
Title: 1991 3.8 mn12 tbird engine swap question
Post by: TurboCoupe50 on September 30, 2009, 08:23:48 PM
The T-5 shifter will come up through the floor at the wrong place and there will be clutch cable(slave cyl?) issues to consider... No doubt doable, but you'll be scrounging a bunch of small pieces...
Title: 1991 3.8 mn12 tbird engine swap question
Post by: cougarcragar on September 30, 2009, 08:42:16 PM
Agreed. You will likely have issues with hood clearance and shifter location. From what I've read, the shifter will want to be somewhere inside the dash underneath the radio.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: jrad235 on September 30, 2009, 09:31:19 PM
I don't think a MN12 ever came with a T-5, Did it? The Mazda 5-speed was all they got, the M5R2.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: DVP on September 30, 2009, 10:31:36 PM
Quote from: jrad235;293297
I don't think a MN12 ever came with a T-5, Did it? The Mazda 5-speed was all they got, the M5R2.


Might want to check with some supercoupe guys.

ThunderbirdUnderground is a cool bunch of guys.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: Beau on October 01, 2009, 02:01:03 AM
Quote from: jrad235;293297
I don't think a MN12 ever came with a T-5, Did it? The Mazda 5-speed was all they got, the M5R2.

Correct you are.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: SR71TC on October 01, 2009, 09:25:38 PM
Well, after seeing my options, I'm just going to repair what needs fixed on the Tbird. I'll just use that as my daily driver and just find another fox body to donate my drivetrain. Thanks again for the input.

~Jason
Title: 1991 3.8 mn12 tbird engine swap question
Post by: V8Demon on October 01, 2009, 11:15:04 PM
Use the motor and an M5R2 get a 164 tooth flywheel.

An intake manifold from a 91-93 Cougar of Tbird should not be too hard to score.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: SR71TC on October 02, 2009, 04:11:52 PM
Nah, I'll just keep this one stock. I'm really not a hugh fan of the MN12 body style in the first place. I'll keep my eyes peeled for a fox body to put my 5.0 and T5 in.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: DVP on October 02, 2009, 09:43:24 PM
Quote from: SR71TC;293483
Nah, I'll just keep this one stock. I'm really not a hugh fan of the MN12 body style in the first place. I'll keep my eyes peeled for a fox body to put my 5.0 and T5 in.


Good plan.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: joker77_2005 on October 07, 2009, 01:26:39 PM
a mn12 cougar with a 5.0 5 speed is alot of fun,i converted my 89 cougar sc 5 spd over to the 5.0 and it is just a blast
mike
Title: 1991 3.8 mn12 tbird engine swap question
Post by: bhazard on October 07, 2009, 01:51:45 PM
Quote from: joker77_2005;293978
a mn12 cougar with a 5.0 5 speed is alot of fun,i converted my 89 cougar sc 5 spd over to the 5.0 and it is just a blast
mike


You know they only made like 2,200 of those, right?

Though they only made 800 in 1990. But still thats a rare car.
Title: 1991 3.8 mn12 tbird engine swap question
Post by: joker77_2005 on October 07, 2009, 01:55:26 PM
Quote from: bhazard;293979
You know they only made like 2,200 of those, right?

Though they only made 800 in 1990. But still thats a rare car.

yea when i bought it,it had a rod hanging out the block,i never was a fan of the supercharged 3.8
mike
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