3.4L swap (edited)

[slow'n'steady]

i am fairly new to the fiero world, i have an 87 2.5L 5 speed notchy. i am debating doing an engine swap because the 4 banger just aint cuttin it.
people say to jus swap in a 2.8L but i figure if im gonna do all that work why not jus go 3800SC. i dont plan to do much else to the car except a fastback conversion and some integrated side scoops along with some other minor body mods.


stuff i know i need to change:
engine
wiring harness
ECM
motor mounts
exhaust
fuel pump
im guessin some fuel line needs to be added

theres a lil i thought of right off hand, i KNOW there is more to it than that, so what all else is involved?? hoping to get it all said and done for roughly $2K???

[Aaron]

i am fairly new to the fiero world, i have an 87 2.5L 5 speed notchy. i am debating doing an engine swap because the 4 banger just aint cuttin it.
people say to jus swap in a 2.8L but i figure if im gonna do all that work why not jus go 3800SC. i dont plan to do much else to the car except a fastback conversion and some integrated side scoops along with some other minor body mods.

theres a lil i thought of right off hand, i KNOW there is more to it than that, so what all else is involved?? hoping to get it all said and done for roughly $2K???

FINALLY someone with a fucking brain!

If 93hp pisses you off enough to want to do an entire engine swap, you think 135 is going to be any better? GODDAMN that is what I hate about Pfiffle, they suggest the Boat Anchor over the Dukeee, when the swap is just as expensive as a 3.4 OHV, even a 3.4 DOHC. Its about time someone realized that 135hp isn't going to be much better, and that there is a reason people swap OUT the 2.8l. Yes, I agree with you 100%.

You ought to look into the 3.4 DOHC as well as the L67. They can be found for a lot cheaper, are easier to swap, and provide similar performance, yet a limited aftermarket.

As for the 3800 II SC, I'd say about $2000 minus the cost of the motor. The L67 has a very high resale consider its popularity and reliability. Even junkyard motors get installed and run PERFECTLY. But they aren't cheap, considering its every 1st gen W-body owner's dream motor (*rolleseyes*), J body guys liek to swap it, as do a lot of other owners. So my uneducated guess would be around $5000 with a motor.

[Series8217]

Aaron's just about on the money there, literally. However, manual or automatic is gonna make a beeeeg difference. I realize you have a 5 speed now, but do you still want one with the 3800SC or whatever else you decide to do? It's going to be more expensive. Keep in mind need a $300 clutch setup minimum.
My 3.4 TDC swap cost $1300 without the motor. I fabricated everything myself, including the exhaust. I spent over $1500 on the motor (including the used "core") freshening it up and installing a reground crank and new bearings, timing chain, timing belt, spark plugs, wires, gaskets, etc. The intermediate shaft bearings failed soon after I installed it and fucked everything up. I have to completely rebuild it.
The moral of this story is: don't buy a used motor unless it has a great warranty and you'll have the swap done in time to actually use the warranty. It's worth an extra $500+ in my opinion.

[Aaron]

I am all about the money. Don't do it if you can't afford to do it to the best it can be done.

You can find a decent DOHC motor for $500, and if you get it off a forum, not Ebay, chances are it will be well taken care of with synthetics and such.

Then get a harness from Erik, and the rest of the install is all but identical to that of a 2.8l.

But, I am biased, bigtime. I feel that the DOHC is the BEST motor for the Fiero, period...And that can be argued easily...

Edit-I misread your post, I thought you were dissing me, saying I was all about spending money, not worrying about price. Which is slightly untrue, there is a reason I have a $1000 V6 and not a $5000 N*...

[Series8217]

I was saying that your post was accurate.

Another thing I forgot to mention to the swapper. I dont think there is an off-the-shelf flywheel that works with the 3800 and a manual transmission. You have to have one modified. More $$$$.
The 3.4 DOHC swap is also much better documented.
If I could do either one with a manual transmission I would pick the 3800SC. I can't do the 3800SC with a manual transmission in California, so I picked the best motor that could be done legally with the 5 speed (the 3.4 DOHC).

[slow'n'steady]

OK ill prolly do with the 3.4 if it is easier to do, what cars and years can you get the 3.4L from? what would be the best way to go about the 3.4 swap? do i need to get a GT cradle or will my 2.5L cradle get the job done? also not including the engine, wiring harness, exhaust, ECM, what extra expenses will i have to spend.
can you'all put together a list of what i need, so i know i have all the basis covered, i will do some more research when i have time, but ive benn workin 60 hour weeks, which prolly dont sound that bad to some of you, but im only 19 and this is my first "real" job, so i think it SUX.. ne ways thanx for the help so far, and any additional info would be greatly appreciated!

[slow'n'steady]

heres the car ive found so far with the 3.4L i need (i think) are there any more?


1991-1994 Lumina Z34 and Euro 3.4
1995-1997 Monte Carlo Z34
1995-1997 Lumina LTZ and SE 3.4
1991-1997 cutlass
1991-1996 Grand Prix GTP and SE 3.4

[Aaron]

That is pretty much all of em, I can't think of any others.

I don't know much else about the swap itself, but search over at pfiffle, there are numerous build threads with hundreds of pictures.

Also, check out http://www.dohcfiero.com

That site alone is priceless.

[Blue Shift]

A thing that people seldom mention or ask, is how long are you willing to have the car down and out of service for? How much money can you realistically spend? Is going past your budget something you can handle? Pulling a stock 2.8 and replacing it (or putting in a prepared 3.4L OHV) could be done in one or two highly motivated weekends, maybe a month tops. Going up from a 2.5 is going to require a bit of extra work replacing all the supporting hoses and wiring with V6 stuff and changing engine mounts.

The 3.4L Pushrod motor is without a doubt the simplest non-stock motor to install. Going up from a 4banger is more difficult, but all the required "swap" parts are easily found in the junkyard on ANY V6 Fiero. Cheap, simple. Don't expect more than 140 RWHP though, unless you go with one of those Truelo intakes, a cam, and headwork. People have dynoed at 200 HP, finally matching carbed 3.4 numbers now that the intake exists to help with the airflow, but that costs quite a bit to do. Unless you get radical, the 3.4 OHV is by no means a screaming demon, and should be thought of as a slightly warmed over 2.8. Going from a 2.5, you will without a doubt notice the difference. Out to kill Rustangs? You'll need a bigger motor, budget, and timeslot.

That's why I went 3.4L DOHC - it's the biggest engine I could legally pass the BAR exam here in CA with a 5 speed, and had a lot of great features like a 7 grand redline and 200+ HP fresh from the donor. But has several people have found out - you better be prepared to rebuild that bad boy - so far, several people who used a JY motor has had to rebuild, so be ready for that. When I decided to do my 3.4L DOHC swap, I figured I'd have my car down for a month, perhaps 3 and it'd all cost me a couple thousand bucks. It's been 8 months and over 6 grand so far. All I can say is that you have to embrace the possibility of setbacks, accidents, and things you can't predict going wrong and be ready to handle it.

Never jump into an engine swap thinking it'll be a simple weekend project. Take what you expect to spend, and double it, they say. Good luck.

[slow'n'steady]

maybe i should jus sell my fiero and finish my srt4 swap into my 95 neon, that will put down atleast 350WHP i can put it into my car and into the 400+HP range for under $1500.

i like the way the fieros look and handle, but if its gonna cost that much and be that much of a pain and im still gonna be slow, whats the point?

[Aaron]

maybe i should jus sell my fiero and finish my srt4 swap into my 95 neon, that will put down atleast 350WHP i can put it into my car and into the 400+HP range for under $1500.

i like the way the fieros look and handle, but if its gonna cost that much and be that much of a pain and im still gonna be slow, whats the point?

You typically won't run $6000 into a motor, he just had really really bad luck.

Assuming you find a good DOHC, under 100k, that has been taken care of, the swap can be done for under $2000, even lower.

Engine: $500-$800
Clutch: $400
Mounts and Misc: $500
Gaskets and exhaust: $300

That doesn't cover every little thing, but it leaves $500 for misc things liek fuel lines and such. So I think it can be done for under $2000, and it will be perfect without any problems assuming the motor you get was taken care of.

[Shaun41178(2)]

I say finish your neon.

Even with a 3.4 dohc it will get stiomped by your neon. And pretty much anyting else worth racing.

[eHoward]

Put the SRT-4 drivetrain into the Fiero.

maybe i should jus sell my fiero and finish my srt4 swap into my 95 neon, that will put down atleast 350WHP i can put it into my car and into the 400+HP range for under $1500.

i like the way the fieros look and handle, but if its gonna cost that much and be that much of a pain and im still gonna be slow, whats the point?

[BigRedDeckSpoiler]

heres the car ive found so far with the 3.4L i need (i think) are there any more?


1991-1994 Lumina Z34 and Euro 3.4
1995-1997 Monte Carlo Z34
1995-1997 Lumina LTZ and SE 3.4
1991-1997 cutlass
1991-1996 Grand Prix GTP and SE 3.4

If you want to retain the stock Fiero ECM, distributor and intake and exhaust plumbing, you will need the iron head 3.4 that came only in the 93-95 Camaro. You'll have to drill holes in the block to relocate the starter. Not a big deal, though.

There are lots of variations on the 3.4. This one is the easiest.
It probably also makes the least power of any 3.4 swap, but the aftermarket has gotten a bit better over the past few months. (Trueleo intake). The gap has narrowed considerably.

[Aaron]

heres the car ive found so far with the 3.4L i need (i think) are there any more?


1991-1994 Lumina Z34 and Euro 3.4
1995-1997 Monte Carlo Z34
1995-1997 Lumina LTZ and SE 3.4
1991-1997 cutlass
1991-1996 Grand Prix GTP and SE 3.4

If you want to retain the stock Fiero ECM, distributor and intake and exhaust plumbing, you will need the iron head 3.4 that came only in the 93-95 Camaro. You'll have to drill holes in the block to relocate the starter. Not a big deal, though.

There are lots of variations on the 3.4. This one is the easiest.
It probably also makes the least power of any 3.4 swap, but the aftermarket has gotten a bit better over the past few months. (Trueleo intake). The gap has narrowed considerably.

The gap hasn't narrowed at all, and we are talking the 3.4 DOHC.

Normally aspirated, I think the highest number for a 3.4l OHV Fiero is just over 200whp. Now considering the DOHC in a Lumina is the exact form as it is in the Fiero, the highest n/a we have seen is 257whp, and that is on stock cams, stock block, stock intakes, stock exhaust manifolds. It has ported/polished heads, and tuning.

The OHV aftermarket has been growing, but remember, so is the DOHC. And every mod done to the DOHC is going to add nearly double the power.

[Series8217]

Normally aspirated, I think the highest number for a 3.4l OHV Fiero is just over 200whp. Now considering the DOHC in a Lumina is the exact form as it is in the Fiero, the highest n/a we have seen is 257whp, and that is on stock cams, stock block, stock intakes, stock exhaust manifolds. It has ported/polished heads, and tuning.

The motor isnt in the same form. Factory cold air intake, and way shorter/better flowing exhaust in the Fiero. Don't forget the Fiero also doesnt use the power steering pump, so there is less drag from the accessories too.
I would not be surprised if that motor put down closer to 270 in a Fiero.


slow'n'steady, what makes you think none of these engine swap observations apply to your Neon swap? You already have every single piece you need including the motor and mods to be at at least 350whp and it was $1500? I doubt it.
If I had all that stuff I would just put it in the Fiero.

[Aaron]

Normally aspirated, I think the highest number for a 3.4l OHV Fiero is just over 200whp. Now considering the DOHC in a Lumina is the exact form as it is in the Fiero, the highest n/a we have seen is 257whp, and that is on stock cams, stock block, stock intakes, stock exhaust manifolds. It has ported/polished heads, and tuning.

The motor isnt in the same form. Factory cold air intake, and way shorter/better flowing exhaust in the Fiero. Don't forget the Fiero also doesnt use the power steering pump, so there is less drag from the accessories too.
I would not be surprised if that motor put down closer to 270 in a Fiero.

What I was trying to get at was that the motor in the Fiero isn't like it would be in the Camaro, you use the Fiero intakes, which may be more or elss restrictive than the Camaros. Basically, there is probably higher than 200rwhp in a Camaro N/A, but it is done with parts that connot be used on the Fiero easily, mainly, the intake manifold.

The DOHC, as far as all critical elements go, is in the exact same form, so theoretically the 257fwhp in the Z34 would drop RIGHT INTO any 3.4 DOHC Fiero, unlike the Camaro, which would need different intakes and headers, etc.

I agree the DOHC in that Z34 could do 260+ in a Fiero. But he has also faced a lot of criticism regarding his runs. I'll be the first to say that his runs are bullshit, and there is little doubt in my mind, even though he posted the dyno chart. With the 1/4mi he ran, and his stock numbers, there is no way he's at 257 with the amount of work he's done. But, fact remains, the DOHC has hit 218whp with the factory intake and exhaust manifolds, and would drop right into any Fiero so long as a stock 3.4 would.

[slow'n'steady]

i think ill jus finish buildin my 400+HP neon, leave the stock 2,5L in the fiero and jus make it look nice, heres a little im doin to it.

integrated rockers, hood scoop(front 4"cowl, rear mustang style scoop) put some nice WIDE wheels on the back, prolly like 17X10 rear and 15X8 front, dual exhaust outlets, ill leave the int. sense its MINT, but the body will be molested.

unless anyone is interested in buying a blue '87 DUKE, with around 100K, 5 speed, in GREAT condition (well everything but the engine( it has been sitting sense 1994 has VERY minimal rust, non running at the moment but soon to be a running car (couple 3 weeks or so)

when i get it running ill prolly say $2500 OBO

[p8ntman442]

when i get it running ill prolly say $2500 OBO

HAHAHAHAHAHAHA :knob:

[JamesCurtis]

to each his own, i know I bought my 88 gt 1 & 1/2 years ago for $2500. It had 83k miles on it and was in GREAT condition. You might look for a more realistic price if you actually plan on selling it :thumbleft: