Where do I even start with an engine swap? (Page 1/1)
Additivewalnut AUG 23, 05:53 AM
It's all in the title, I've been looking around at some 3800 SC's around my area and figured I would build one up a little bit and throw it in my 86. I've been doing some reading around the forum and on west coast fieros' site but YEESH is it overwhelming. I guess what I'm asking is, where do I start?

All my reading has got my head spinning with flywheels, wire harnesses, motor mounts, whether or not to use a dogbone, building my own axles, alternator brackets, coil mounting spots, battery relocation, injectors, etc etc. It's just so much.

I've never done a swap if you can't tell.
Will AUG 23, 08:22 AM
Basics first: Do you have a place to do the swap? The process of powertrain R&R for a Fiero is more complicated and requires different equipment than front engine cars. The powertrain comes out the bottom, so you need the capability to lift the car up AND drop the engine out at the same time.
darbysan AUG 23, 10:29 AM
You are doing the right thing by studying. Get a 3 ring binder, section it off by the project areas needed to get you where you want to go, and start keeping notes / printouts as you go along. You will likely change direction more than once, but planning ahead makes the project so much easier. If you just jump in , it will take longer, and cost more money, than you thought it might. Do the same thing in your internet "Favorites" folder. See something you like, or that reminds you to do something- save it! You can also build a spreadsheet with projected parts and costs, as as you buy something, either flag it on the spreadsheet as bought, or add it if it wasn't there before. Finally, build a project plan ( a to-do list sort of). Do this on paper, where you can make changes / additions as yo go along. A spreadsheet or Word doc is a good idea. Estimate not only cost, but time. This might help you with space requirements as well as time / money budget. You can also do some of the projects early, like Cooling, better brakes / suspension, Battery move to front , while still driving the Fiero.

As far as the 3800 goes, good engine choice. Finding the right donor will help a lot. I like the GTP Grand Prix, as you can use the trans, some of the axles parts, the front accessories, and most importantly the engine wiring harness including the fuse box. Building one up- I would do that only if you are a very experienced engine builder. Lots of one-use only bolts in the 3800 engine, plus not that many available parts. Won't find many machine shops that will even do a rebuild on them. I guess a lot depends on what your goals are for the car- driver, show car, drag racer, etc., and what engine output you need to meet those goals. The trans you choose will be a factor as well. The 3800 swap is well documented, but you should still expect dozens of "engineering" problems to arise during your swap that you have to figure out a solution. It is a fun swap, but a lot more complicated than just swapping in a bigger SBC in a Camaro.

There are simpler swaps , the 3400 being probably the easiest ( almost a bolt in). It's not as much HP as a SC 3800, but it has gobs of low end torque, which makes the stoplight race nearly as much fun, and would be lot cheaper.

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'87 GT , '00 3800 Series II SC, 4t65e, Vue Power Steering. (SOLD)

fierosound AUG 23, 10:32 AM

quote
Originally posted by Additivewalnut:

YEESH is it overwhelming. I guess what I'm asking is, where do I start?




You have to break it down.
And write it down, don't try keep it all in your head.

ONE step at a time... the "big bits" first.

Decide what engine, what transmission...
Sounds like 3800 S/C with the manual transmission you have is how you're leaning.
Appropriate flywheel can be bought from Fierorog.
http://www.fiero.nl/forum/Forum4/HTML/067149.html

Clutch can be any clutch listed for Fiero transmission you have.
Transmission mounts locate powertrain on cradle.

That will help see what needs to be done for front engine mount.
Fierorog also makes swap parts for this to make things easier.
http://www.fiero.nl/forum/Forum4/HTML/068855.html

This gets your powertrain on the cradle.
Use the axles you have now.

Swap harness can be bought, or you can make your own once you have your ECM.
http://www.gmtuners.com/files/index.htm

After that point, all the other details can be worked out as you progress.
Lots of info on alternator mounts, exhaust etc. online.


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My World of Wheels Winners (Click on links below)

3.4L Supercharged 87 GT and Super Duty 4 Indy #163

[This message has been edited by fierosound (edited 08-23-2020).]

sourmash AUG 23, 12:35 PM
At your level of current understanding this specific swap, don't start by tearing the old car apart. Most times that's where the project stops and then you've got something almost nobody wants plus your parking area is now unusable. Maybe acquire another cradle to build the new swap on. Start from the bottom up. 1) Cradle 2) mounts 3) long block 4) clutch/trans 5) accessories layout [alt, idler, belt] 6) maybe now the wiring harness 7) then what's left to do? You have drive axles, exhaust, cooling, linkages, and (?).