So as i posted before i have a 3.4 SFI that i'm looking to swap into my 3.1 MPFI. I bought the engine complete, all it needs is a new headgasket. Can i just buy a rebuild kit with gaskets and seals and just reseal what i have attach the transmission i also bought and hook it up to my stock setup?

Specifically is there any sensors that need to be changed for the ECM to work properly? Will I run into any problems taking this way out?

I've read all the swap articles and they are for when you take one block and swap your existing parts on, but the engine i have is complete.

 

If the headgasket is trashed, you should be sure the mating surfaces are level (deck and head) before you just start changing gaskets. You can check the block with a straight edge, and its probably best to disassemble the head and have it resurfaced. If the deck/head have warped because it overheated, it'll keep blowing head gaskets until everything's flat again. It'd be best to call a machine shop and ask them what they think- even better if you bring the old head gasket because it will give a clue as to why it failed.

I'd think it'd be more work and $$ trying to adapt/measure/convert the 3.4 hardware rather than just put your 3.1 equipment on it. But it's your car, give it a try and let us know how it goes! You'll be making adapter harnesses, you should measure the values of each sensor to make sure they correspond to the values that your 3.1 computer expects, etc.

 

The sensors should be very similar. Make something to connect the fuel lines and some rewiring and it should work just fine after recalibrating the ve tables.

 

Just my 2 cents, but there is a very good reason that almost everyone does a hybrid build using their old intake setup, its better, and easier, to use the full 3.4....you will have some work on your hands....

 

your actually not gonna be able to be lazy by doing it that way, all you have to change are the accessories on the front of the motor and the intake stuff. not hard just do it that way, there is a reason why everyone else did

 

Oh ok, thanks guys.
So before i buy the rebuild kit, i.e. gaskets and bearings.
Just to be clear so i don't screw it up.

I'm building as if it was a 3.1L so it adapts to the sensors and everything. I've learned that i need to reuse my distributor and fuel rail. But buy a new water pump and sensors. So then i'll buy the 3.4 gasket and bearing set, but use 3.1L accessories?

The reason i'm confused is because all of the swap articles tell you how to do it, if you take your current engine and the new engine out at the same time and i'd rather just put new parts on the 3.4 and not take my car out of service for that long.

 

Before you start re-gasketing, don't forget to check the head and block as I mentioned above...

 

I definitely will i'm doing this in my power mechanic's class at high school so i'll definitely clean both the block and head.

I've already started disassembly but i still have a few questions:
What rebuild kit do I buy the 3.4 or the 3.1?
Since I want to keep my car in use during all of this what 3.1 components do i have to buy besides the distributor?
Are the only things that i have to replace with the 3.4 parts the water pump and the sensors?

 

bump

 

Oh, more questions. Buy the gasket kit for whichever induction you plan on using. You can use head gaskets for the 3.1 on the 3.4 despite the bore difference. I did on my motor. You need the distributor & coil for the 3.1 to use your stock ecm. You may need the fuel rail as well, I've been told they use different fittings but you may need to do some minor fabrication anyway, like hooking up the egr. Technically this would be an illegal combination because when you retrofit a motor you need to retrofit all the emissions components (including pcm and ignition components) respective to the newer motor to the recipient vehicle, but I doubt you'll ever get flagged for it at an emissions station. Which sensors you use depends on which induction you're using, they won't interchange between throttles but the CTS will. And the water pump you use also depends on the induction you use because you want the gasket kit you buy to match the pump you use. Clear?