New fiero owner, already doing a swap

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FieroAK

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Hello all. My name is Zach and I am new to the Fiero world. Man this feels like an AA meeting. Haha. However, I have an 1985 Fiero classic with the dinky 2.5L, purchased from some lame used car dealer last year. Needless to say... two weeks of driving and the engine over heated and knocks like crazy. So it's sat, since... August of 2010... I bought another Fiero, same engine, no title, for $200 with a bad transmission, and am currently swapping the two motors so it's driveable. But my real question is... well, one of them... is I have a 1991 Cavalier Z24 with a 3.1L V6, is that an easy engine to put into a Fiero? The Cavalier is sporty, and just sits in my driveway. It is fuel injected, which I know can cause some difficulty with an install, but would the effort be worth it. i know nothing of the car and research gives different answers. Second question is, if the 3.1 is not doable, what are some good ways to keep the 2.5 cool and are there cheap ways to up the performance?
 
Yes the 3.1L will swap in easily. Fieros came with 2.8L V-6's and the only difference between the 3.1L and the 2.8L is the crankshaft and pistons.
The only things you will need to do is to use the computer/engine harness with the 3.1L engine and change the fuel pump to the V-6 Fiero fuel pump.

FYI ~ Nearly any GM engine will fit in a Fiero and has been swapped. I have a Chevy 350 V-8 in mine. The 3800SC is another popular swap. Even Cadillac Nortstar engines have been swapped.
 
I'd love to do a 3800SC swap, but I have no money and locating one isn't that easy around here. But with the 3.1L, is the performance and mileage worth the work? I assume that is gets worse gas mileage than my 2.5L, and I'm not sure what performance the '91 Z24 Cavalier's had.
 
pull the engine from the cavalier and sell me the roller
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So for the 3.1L I'd need the fuel pump for a 2.8L Fiero. I read that the 3.1 and the 2.8 have the same HP, so is one better over the other in any way?. Alright. And the computer from the Cavalier. But will all the gauges and whatnot still work properly or how will that work out? The Fiero is currently my only working car so in and out of the swap the fastest would be best and I'd want to be prepared before-hand.
 
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FieroAK said:
So for the 3.1L I'd need the fuel pump for a 2.8L Fiero. I read that the 3.1 and the 2.8 have the same HP, so is one better over the other in any way?. Alright. And the computer from the Cavalier. But will all the gauges and whatnot still work properly or how will that work out? The Fiero is currently my only working car so in and out of the swap the fastest would be best and I'd want to be prepared before-hand.
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2.8L 140 hp
3.1L 150 hp

3.1L has larger oil galleys allowing oil to flow better.
The gauges and all other accessories will work fine. They are not controlled by the computer. I have a carb'd V-8 and removed the computer. All gauges/accessories still work fine.

If you have a parts car, Build up the spare cradle with the 3.1L and when you are ready to do the swap, Just swap the cradles. Takes about 6-8 hours to swap.
 
I do have a spare car, another 85 Fiero, but it has a bad transmission. I only have the one working Fiero transmission, and I'm not sure if the one in the Cavalier with the 3.1L will work in a Fiero chassis. 150HP would be nicer than the put-put speeds of the Iron Duke, but it's not a project I can start just yet. Information would still be nice.
 
If you are going to do the swap to the 3.1 and a later time, Why not take the trans in the 85 and get it rebuilt? What I would do is take the cradle and trans from the 85 and have them cleaned and repaired. Then take the 3.1L and modify it. Port the heads, toss in a bigger cam, a performance intake like the one here: www.trueleo.com
A nice set of headers, and a nice clean-up. Then when it is all done do the swap. It may cost $1000-$1500 to do the work, But if you do a little at a time over the course of a year, You could do the swap next spring and have a nice engine with more power (probably in the 180-200hp range) and know it will last many miles since it is all rebuilt like new.
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I will definitely keep that in mind about the 3.1, if I don't turn the Cavalier into a back-up car. For the time being, are there any good ways to keep the 2.5L temperatures lower? Have a low temp thermostat, and more vents on the decklid, but I don't want it to fail on me like the last 2.5L did, so anything that will help, would be appreciated.
 
FieroAK said:
I will definitely keep that in mind about the 3.1, if I don't turn the Cavalier into a back-up car. For the time being, are there any good ways to keep the 2.5L temperatures lower? Have a low temp thermostat, and more vents on the decklid, but I don't want it to fail on me like the last 2.5L did, so anything that will help, would be appreciated.
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To help keep the engine and cooling system running efficiently there are a few things that can help.
http://rodneydickman.com/catalog/product_info.php?cPath=21&products_id=95 sells low temp fan switches. The stock ones turn on around 235* Rodney sells a couple that turn on at 185*, 195*, 200* and 210*

http://www.v8archie.com/v8Archie/Prod7.htm sells a hood with a vent in it. This has two benefits. First, it allows the heat and airflow thru the radiator up front to flow out easily. Second, it removes air pressure from under the hood during highway speeds keeping the car very stable. (handles a lot better). He also sells a 4-core radiator. It is typically used in his V-8 swaps but it can be used in any Fiero. Fits into the stock location with no problem. To save a little money you can just get a V-6 Fiero radiator as well. Most auto parts stores sell them and you will eventually need it if you go to the 3.1L.

The last thing is to inspect the cooling tubes that run from front to back on each side of the car. If someone raised the car up on a lift or a jack they could have accidently crushed or deformed these tubes. This will restrict coolant flow. If yours are damaged, you can get replacements from www.fierostore.com

Hope this helps.
 
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Well for the venting of the engine compartment I have the decklid that came with the car, that has a few vent slots in it. But also the car that I got for parts had those two rectangular pieces to each side of the decklid that are vented, where as my car they are solid. So with all those I have a line of vents behind the entire rear window all the way across. I checked the coolant lines under the car and they all seem to be in good shape. Something I noticed today was that whoever had the car before me... put the thermostat in upside down... so I am fairly sure that contributed to the overheating in some manner. I will look into getting the radiator for the V6 Fieros to replace mine, as well as the lower temp fan switches, though currently I have it rigged to a toggle, an automatic one would be better. is the stock fan decent enough or should I get an after-market one, such as Hayden? Thank you for all the suggestions.
 
FieroAK said:
Well for the venting of the engine compartment I have the decklid that came with the car, that has a few vent slots in it. But also the car that I got for parts had those two rectangular pieces to each side of the decklid that are vented, where as my car they are solid. So with all those I have a line of vents behind the entire rear window all the way across.
Click to expand...

You misunderstood me. I said the hood. Meaning the one on the front of the car. If you vent it just above the radiator, You will increase cooling efficiency.
See the like for the hood I posted previously.
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Sorry, usually around the time I get to the computer I've been awake and busy all day. Comprehension usually gets to bed before I do. Lol. I see what you mean, that would help cooling a lot.
 
I have another question, this one being something that's been pissing me off the last few days... the wiring harnesses are different from the 2.5 that was mated with the 5-speed manual, and the 2.5 mated with the automatic. And the two engines use different distributors so the wiring is different there. Is anything splice-able?

Also I can't seem to find the torque specs for the flywheel bolts on the 2.5L. If anybody happens to know them, that would help me a lot.
 
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