Paranoid

ok im doing a 2.8 to 3.4l swap in 89 firebird, i got i think pretty much everything that is bolted to the 3.4 (from a 1994 firebird ) for i should have everything i need, but the 3.4l came out of a manual so im not sure. but anyway what im wondering is

1. do i need the computer/chip from 3.4l or do i just leave it as the 2.8l computer?

2. can i use the flywheel from the 2.8 to replace the clutch assambly on the 3.4?

3. Is there anyway to use the 3.4 oil pan because my 2.8L one has a crack in it?

4. do i use the distributer out of the 2.8 or am i suppost to modify the car to use the coil assambly on the 3.4?

5. and do i need to change the water pump from the 2.8 to the 3.4 or leave the 3.4's?

Paranoid

oh also,

5. do i use the exhause manifolds from the 3.4 or the 2.8 and if the 2.8 do i use the heat shields off the 3.4 ones?

Parrydise7

iTrader: (1)

Since you are a newb, the first thing to do is always check the search function. Second of all, check the technical articles, because there is a technical article called the 2.8 to 3.4 swap boogie, or something like that.

Since the 3.4 is a bored and stroked version of the 2.8 (IIRC), there is a great deal of commonality of parts. But, since it has been so long since I swapped the 2.8 out for a 3.4, check the tech article. I don't want to steer you wrong.

BTW, that 3.4 is a much better engine than the 2.8 and should make for a very nice car.

One other thing, somebody used to make an adapter to bolt to a f.i. base manifold to adapt 3x2 Weber carbs. I haven't seen one of those in a long time and don't count on passing smog.

Good luck.

Project: 85 2.8 bird

yes, read teh 2.8~ 3.4 swap boogie by KED85. Also, Dale has done up an article on his swap also. Pics of mine are in my cardomain link.


1. 2.8 computer

2. get a 3.4 flywheel

3. yes, I ran w/the 3.4 oil pan when I had mine in however *

4. 2.8 dizzy

5. well *

* oil pan use will be determined by the oil pan gasket/front cover. Swap over the 2.8 cover & get a new oil pan for swap.

5. Keep teh exhaust manifolds on the 3.4 heads, & keep teh o2 sensors there as plugs.

Paranoid

i have read article, but i didnt seem some of this stuff or i missed it. but with your answer i have one or 2 more questions.

1. the 02 sensors on the 3.4 manifolds if im not mistaken theirs not a plugin for them anywhere that i know of.

(screwed up my numbering)
2. and do i need to change the water pump from the 2.8 to the 3.4 or leave the 3.4's?

3. and did you have to do anything special to use the 3.4 oil pan or did you bolt it in. becuase im kinda on a very limited budget here.

4. and this one is from my dad, do we need to change over the harmonic balance since the 3.4 has a knock sensor and the 2.8 doesnt?

(im sorry if these are answered int he tech articles the section doesnt seem to be working right now so please bear with me)

Parrydise7

iTrader: (1)

IIRC the water pump are identical.

Compare those oils pans. I had to re-use my original 2.8 pan because the 3.4 wouldn't clear the suspension (but then I was replacing a 2.8 in a Jeep, so you might not have the same problem).

Can't help with the other questions. Good luck.

Paranoid

i was just wondering will i need the pipe and the air pump on the exhause manifolds or can i just plug the hole?

Parrydise7

iTrader: (1)

Is that a smog control device (it sounds like it, I just want to make sure)? If so, if you have to go through a smog check (like here in California), then yes.

You might also want to try posting on the V6 board. You might get individuals that are more familiar with the V6.

Paranoid

yes i do have to pass emissions. but thats like the one thing the motor didnt come with was the air pump.

Parrydise7

iTrader: (1)

There might be some exception if the part is no longer available. Check with a local smog shop and see what they say.

Paranoid

ok thanks

Project: 85 2.8 bird

I had absolutley NO clearance issues using the 3.4 oil pan for my swap.

Water pump on the 3.4 rotates CCW, if your yr 2.8 doesw also, then you're golden. Otherwise put the 2.8 front cover on the 3.4 and bring over your 2.8 water pump.
The waterpump on my 85 2.8 rotated CW, you must check on this for the car to cool right/at all.

For the 3.4 o2 sensors.... don't worry about a plug, as they are the same as teh 1wire i the exhaust pipe. Now you have 2 spares. Keep teh one in the y-pipe hooked up.

Reuse the 3.4 balancer alog w/a 3.4 flywheel.

Transferr your air pump & bracket from the 2.8 to teh 2.4. You mayend up haveing to swap front covers anyway.

Also, check the timing chain for stretch while you're at it.

Paranoid

im hoping this is ok but we decided to go with the 2.8 exhaust manifolds since their the same size, and we cant find and air pump for the smog system.

redbird8628

iTrader: (1)

its up to you, but since the water pumps are the same, leave the cover on, and transfer that timing mark over from the 2.8 timing cover over to the 3.4 cover, you can bolt it to the cover by removing the cranks sensor and using one of the bolts from the crank sensor to hold it on, it WILL work, just find #1 tdc to get it about right, saves alot of time, but if that cover is leaking might as well do it and have new seals and be leak free. also, all the AIR pump does is inject air to heat the exhaust to burn what feul is left in the exhaust, it wont really effect emmisions, i made it through fine with a high flow cat on there too., just cut the wires off the 3.4 oxygen sensors and be done with the manifolds

redbird8628

iTrader: (1)

oh, and the 2.8 was offered with and without an air pump, sooo, get a belt that is meant for no air pump, you'll be ok

Paranoid

so umm im about 2 days away from starting my motor, and my dad seems to think that i need a 3.4 chip for the 2.8 computer, is that true?

Paranoid

also, theres 3 wires going into the front of the 3.4 block, right infront of the intake, and i cant seem to figure out what it is?

Project: 85 2.8 bird

pics would be good of teh wires in question. Are they coming out of the block? as it might be the cam/crank sensor which is not needed to be hooked up in the swap.

Paranoid

its right at the front of the block looks like it goes to the cam so i guess cam sensor.

Project: 85 2.8 bird

I just cut the wires o mine as close to teh sensor as possible. no need to remove the sensor.

Paranoid

ok the car is ready to be started but i dont want it running lean, will i need the chip from the 3.4 in the 2.8 computer or just leave the 2.8 computer completely as is

Parrydise7

iTrader: (1)

I think they are the same, but to be sure, check with your dealer. If the part numbers are the same you are good to go.

Project: 85 2.8 bird

no need for new chip unless you;ll burn one/have one burned for that "custom" thing.

Paranoid

well i got it in and their seems to be a few issues, it runs really rough and sometimes when i try and start it it just clicks and does nothing.

Paranoid

ok solved the rough running problem, but it has no *****, and i cant seem to find what the timing should be set to

Project: 85 2.8 bird

I've read that the best timing is between 10* & 12*

Paranoid

wow for some reason the timing dropped back to 0 after we tightened the distributer. put it up to 12 and has so muhc more power