I was wondering if i should swap a 3.1l out for a 3.4l or should i just rebuild the 3.1l cause it has a massive engine vibration and if i swap the 3.4l in do i need to change to obd2? or can i keep the gm1 conector?

 

Lots of things to consider here. How many miles do you have on your 3.1, how many are on the 3.4, how much $$ do you have to put into this project, what is your mechanical abilities, etc etc. Also, the 3.4 is OBDI as well as yours, so there is nothing different..... especially since youll be using the 3.1 ECM. Read up on the 3.4 swap boogie by KED85.

EDIT: May wanna find out whats causing the vibrations. it could be an engine mount or just a new balancer needed.

 

You can get a 3.4 from pick and pull for 250 bucks. I'm sure if you hit a jy or 2 around here you will see that they are full of 3.4s. Its not that bad of a swap I did a pull and drop in a day. I got the 3.4 from pick and pull with less that 50k on it for about $258 and didn't do anything to it. I put it in a lil over 2 yrs ago and still going strong.

 

i think im just going to do a swap because i dont have the money to do what i want to the 3.1l so ill throw a 3.4 P&P motor in it(live in va beach) cause the motor mounts are new and the balancer is new so with that..i have my dad thats helping me hes been a mechanic for about 25 years so he was around when the car was new so no mechanical issue..just he doesnt wanna tear the motor down and rebuild unless im gonna put what i want in the motor so we dont have to keep pulling it in and out..so im thinking the swap to a 3.4 is better then rebuilding the 3.1l cause the 3.1l that is in it i was told when i bought the car was already a junkyard motor with 160k on it so its kinda useless to rebuild a motor with its age

 

ok so i got the old motor out and found out it was a 2.8l and the car was supposed to come with a 3.1l so instead of swapping to a 3.4l cause we couldnt find one that was good in the junkyard we found a 3.1l 198k on it but it looked well maintained so were gonna drop that in there

 

with that kinda mileage, i hope youre at very least regasket and a new oil pump. when you say it "looked" well maintained, what are you basing that on? physical outer appearance or have you opened it up? You may be getting more problems than you had if you just drop it in.

 

That was your problem right there. Except for a few later models, MOST 2.8s were externally balanced, and if the swapper used a 3.1 flexplate on there (that didn't have the balance weight), the engine ended up with no balance weight at all, hence the unbalanced condition.

:edit: And I second the regasket with oil pump and screen, along with replacing the water pump.

 

no im not basing it off physical apperance looking at the lower end and valves it looks well maintained and yes i am doing gaskets and using the water pump i had in the 2.8 cause its the same and its brand new and the oil pump is also new

 

How do the crank and main bearings look, any scoring at all? Personally, if there was that kind of mileage I'd be very uneasy about an engine. What about the cylinder walls, can you see hash marks yet? Have you pulled the cam and looked at the cam bearings? Hopefully it wasn't an impulse buy, no offense to you.

 

yes i have been able to see it all and everything looks very good

 

Ive got the motor completely installed and this car will go for a stock car..now that it has the right motor in the car for the PROM

 

in 2-3 months drop in and give us an update of the swap and how the car is running...


198k - Wow.....thats all I gotta say on that note