new member needs big help

[livingthemudlife]

i got a 1987 comanche that i just got for a hundred bucks. it has a v6 in it. from what i no the motor is a gm but the rear is blown i think the gears are 411s but the plate on the rear is gone someone took it off so i got two question where can i find a rear for it? and i also got a 1995 firebird with a lt1 how hard would it be 2 drop the motor in the comanche and do all the wiring......... I'm making a dirt race truck

[offroader461]

its gotta be an 86 if it has the 2.8 in it....Jeep discontinued that and the 4.0 was introduced in 87...as far as the 5.7...won't be hard just time consuming..

[jtdesigns]

i got a 1987 comanche that i just got for a hundred bucks. it has a v6 in it. from what i no the motor is a gm but the rear is blown i think the gears are 411s but the plate on the rear is gone someone took it off so i got two question where can i find a rear for it? and i also got a 1995 firebird with a lt1 how hard would it be 2 drop the motor in the comanche and do all the wiring......... I'm making a dirt race truck

 

I've worked with the lt-1 before. You can find a wiring harness at a few different places. http://www.tpis.com/

http://www.lt1swap.com/

http://www.lt1350.com/

Mine was a 97 and out of a burnt firebird. your lucky your working with a 95!! The wireing harness is way easier to find.

[JOMJ87]

Whats your location and we can try to find a rear for you. Several members have extra laying around. Oh and if your going to a V-8 you have alot to look into and the rear axle will need to be upgraded instead of replaced with another stocker.

 

Cole

[JeepcoMJ]

I put the Lt1's little bro in my 1986 jeep comanche, which had the same motor as your 86 comanche does. it wasn't that hard.

 

the lt1 will require that you use the camaro tranny with divorced t-case (if you want 4wd) as the lt1 WILL NOT bolt up to any jeep bellhousing.

 

as far as wiring for the lt1, you can use the stock wiring from the car. all you need is the wiring from the engine bay. I can get you all the diagrams you need in order to remove what you don't need, and splice into the factory harness where you need to (will only be spliced into for the tachometer feed, which you'll need a signal adapter for anyways). the engine will run completely seperate of the jeep factory harness, with the only things intertwined being the tach, the starter wire (really just connected to the relay), and the fusibles to power the sensors.

 

IIRC you have a positive output on the Lt1 engine computer for the fuel pump...meaning you install a relay near the engine computer, and run the wire to YOUR fuel pump. I highly recommend installing an in-line adjustable PSI fuel pump, in order to get the pressure where you need it. you will not be able to use any stock jeep fuel pump with the project, as even the 4.0 pump will not be enough PSI and your 86 doesn't have an electric fuel pump...it's mechanical on the block.

 

the only other thing you need is a VATS (Vehical Anti-Theft System) bypass module, supplied by bakerelectronix for $30 plus approx $5 in shipping when I got mine. without that to produce the 48hz (I think it's hz) signal that gives the OK to ground your injectors, your engine will run for approx. 3 seconds before the injectors turn off. that is pin 55 on your ECU the dark blue wire.

 

any more tech you'd need, I can help. you may need slight front uni-frame mods, probably a few hammer-taps to the firewall, custom motor mounts and headers and downpipe (unless you run true duals by removing the tank and throwing your fuel cell in the back of the bed).

 

more info on the 3800 install, which is basically the same wiring system etc., see Project 3800 Powered by camaro in the MJ projects thread.

 

we expect pics of the vehicles to be combined.

[livingthemudlife]

i live in delaware. the whole thing about the lt1... how much do you think it would cost me for the whole swap 2 get it running

 

thanks everyone

[JeepcoMJ]

i live in delaware. the whole thing about the lt1... how much do you think it would cost me for the whole swap 2 get it running

 

thanks everyone

 

are you doing the swap, or paying to do it.

 

you'll spend at least 1500 to have it installed, and probably up towards 3000.

 

I would do it myself if I had any mechanical ability and access to cutting tools and welders etc, because it's really not that hard of a project.

 

the one other thing you will need to do is either switch to a 4.0 radiator and rad. support system, or find a custom radiator that will fit in the comanche frame (the camaro one is too wide...already tried that one).

 

to swap the 3800 into my truck took me 1 month of working on the truck 3 to 4 days a week over winter break from school. I wasn't working too hard obviously, and now that I've done it once, I think I could prefab the parts and have one installed in my truck in less than 2 weeks of 3 days a week.

[DirtyComanche]

If you go LT1... Plan on running a chevy tranny. I'd say built 700R4 for the money (spend $1000 on it at least, or it won't hold up to real world use). You can mate most common tcases to them (the 231 and 241 bing the typical choice) without spending big bucks.

 

 

A friend of mine has one in his YJ. Well, had. It's actually still physically in the YJ, but it had an issue with a rod bearing, so it doesn't exactly run... Anyways, it's a good engine and the wiring harness is easy to work with. If you have the stock harness, it's pretty easy to wire into any other vehicle. Espeically a jeep as they run a GM colum. The opti-spark will commit suicide if exposed to water. MSD makes an upgraded dist. for it that solves MOST of that, IIRC it's about $600. You'll probably want some block-hugger headers, or the oldschool vett cast headers - or you will have clearance issues. You'll want a fuel pump out of a GM truck with a vortec V8 to provide enough fuel for it (the camaro ones are over-priced but the exact same part). You'll also need some serious radiator as they make a lot of heat. The stock camaro one is hard to work with as it has to be mounted at a layed back angle or it won't flow right (or so it seems). However, a large enough aftermarket radiator should be found. Make sure you do this right - heat will kill these engines. You'll want it to be aluminum, and 3-core. Also, the P/S pump on these engines sucks (it's not for a truck...) and you can't really change it (other than PSC's pump).

 

Dunno what else to say. They're tough engines. His had sucked mud and water a bunch of times, and been run at over 280* at least 7 times, and it had about 100K on it when he got it. Not to mention being run on its side without oil pressure more than once... Which was what finially did it in, well, along with a pegged temperature gauge.

 

 

Edit... You might consider a rear mount rad. If you're racing it, that shouldn't be a problem. I run one and am happy with it. It's an easy enough thing to do if you have sorces for the needed parts.

[livingthemudlife]

so what motor is this?

 

here's the rad

 

[JeepcoMJ]

so what motor is this?

 

here's the rad

 

 

 

hahaha wow.

 

it's a 2.8 v6

 

and that looks to be about an 88 that HAD a 4 cylinder in it, converted to a 2.8 v6. in 88 they had the same header panel as the 4.0 cherokee, just and adapter that bolted to that in order to fit the2.5 rad in it. but the 4.0 would bolt right in.

 

anywho, you do NOT want a 2.8 v6. let's just say that if the 2.8 were some sort of food, you'd probably find a bucket of $#!& more appealing to your pallette.

[JeepcoMJ]

looking at the pic further, in the first one I see a 2.5 coolant reservoir and washer fluid reservoir on the driver's side, and the passenger side you can see the relay control center for the 2.5.

 

it's also a manual tranny, and had a/c with the old engine. the builder of it decided upon an open system heavy duty radiator from a 4.0 (good choice).

 

in the second pic, note next to the cooling fan (to the right of it) the two small holes in the upper rad. support and you can see that it used to have something bolted there. that used to be where one of the 2.5 radiator supports bolted to.

 

quite the interesting combination...I wish the guy had taken the time to swap a camaro 3.4 in it at least, but still interesting.

[87manche]

well, at least you've got a good start with all the radiator stuff you need.

 

 

I'd drop in the LT1 with a built chevy trans and t case from a chevy truck. Shouldn't be hard to find one in the yard with a blown up motor.

 

of course, if you're racing it, are you going to keep it 4WD?

 

I'd also plan on doing front and rear axle swaps, as the D35 and D30 aren't gonna live terribly long behind that drivetrain.

 

D44's at the minimum, and I'd seriously consider 3/4 ton or larger running gear.

 

an LT1 is a stout motor, and it will break parts if you get happy with the skinn y pedal.

[FxRacing282]

dirtymanche... nice tranny thinking but 700r4 is a terrible tranny! if its going to be a racing truck either get a turbo350 turbo400 or a 2spd powerglide (may be harder to find but well worth it! my friends dad runs one in the circle and its an amazing tanny)

living the mud life... if a 700r4 is free go with it but expect problems down the road, especially if you plan on racing with it. the tranny off your firebird should work... might take some tlc

[DirtyComanche]

The early 700R4s really sucked... The later ones weren't much better.

 

If built decently, they'll hold 300HP without issues. And the gearing on them is FAR better than a th-350 or 400.

 

I personally don't care much for th-350s. And the 400 is IMHO only marginally better in stock form. A LT1 with an agressive driver could destroy any of them...

[FxRacing282]

its true... but i would just use the tranny he has on the motor now