powertrain swap questions

[robertg]

hi everyone, been a long time since i've posted here.

 

the chassis of my 1990 lumina has rotted away. the drivetrain is in good condition, and i had the back brakes replaced last year (rotors and loaded calipers) . i'd like to find a good donor body, and swap everything over.

 

i'm looking at a 91 or 92 lumina (unsure of the year) with a blown 3.1 engine. what i would like to know is if the engine electrical harnesses are the same amongst all three years. also if coolant hoses are routed the same.

 

i don't have access to alldata or the like, and i'm looking for some used shop manuals on ebay to help guide this swap along.

 

what i'm thinking of doing, is setting the cars side by side. then i would drop the front cradles after unhooking the wiring and coolant hoses (swap knuckles and all), and then swap the back brakes from my 90 over to the donor or hang on to them. also, i'm told my 90 model received an updated plastic fuel tank as part of a recall.

 

any ideas or suggestions?

 

i've replaced the lumina as a daily with a 2000 astro, but i'd like to have the 24 mpg city that i do not get from the van.

 

thanks!

[Robby1870]

Most things will be the same. The cruise control servo will be larger on your 90 lumina, as they changed to a smaller one in 91+, but the connector is the same, so no big deal there. The coolant overflow on the 91-92 might be on the passenger fenderwell as opposed to where I think it is on your 90, right up front. Some routing of hoses might be a touch different, but it should pretty much be a direct swap. Im guessing the trans in each car is the same?

[robertg]

robby: i *think* that they are the same. my 90 has the 4 speed automatic. if they're different, i'll get whatever parts i need to make my 4 speed work

 

yeah, the overflow tank is right up front on the 90.

 

i still work at a parts store, so i can use whatever hoses i need. i have an entire room full of hoses to work with.

[Robby1870]

robby: i *think* that they are the same. my 90 has the 4 speed automatic. if they're different, i'll get whatever parts i need to make my 4 speed work

 

yeah, the overflow tank is right up front on the 90.

 

i still work at a parts store, so i can use whatever hoses i need. i have an entire room full of hoses to work with.

 

If they are both 4spds, then is super easy. If one is a 3spd (I hope for your sake not), it will be a little more difficult. I think it uses different mounting and I know it will have different wiring. If the 91-92 one is a 3spd car, then just use the ECM and wiring harness from your 90. That'd be the easiest way to get around the 3spd. But, that requires pulling the ECM/wiring harness from the 91-92 and putting in your 90.

[robertg]

if it is a 3 speed, i'm probably going to pass, unless i get it for stupid cheap. it's supposed to be fully loaded, so i'm gonna presume that it's a 4 speed.

 

i'm going to strip the 90 completely and keep what parts are usable, then junk the rest. it rotted away where the lower control arm goes from the knuckle to the body (directly underneath the rear seat) not the lateral link that goes from the center of the car to the knuckle.

 

we'll see what happens.

[Robby1870]

Sounds like a fun time. Working on rusted cars is an experience.....where goggles. If its "fully loaded" it should have the 4spd. Good luck and keep posting if you have any other questions.

[robertg]

i farmed out the back brakes on the 90 last summer due to rust. they were also the originals with 156k miles on them.

 

thanks again!