So my 2.8 blew, got a line on a 3400 from an 05 impala. i want to tear it down and install my fiero uppre end on top. how well do you think this will work?
In my opinion, the little bit of effort/cost required to keep the 3400 top end is well worth it. The heads and intakes flow much better and the engine runs much smoother and gets way better mileage.
There's about 5 or 6 people on the forum that I know of who maintained the Fiero top end and are quite happy. For a while I was using the Fiero ECM but had problems when I switched to the '7730 swap because my knock sensor wires and crank position sensor wires got too close to header and were resting against the block.
If you're running the Fiero ECM - it will work great. If you are also going to upgrade the ECM then you just got to take care and route everything properly.
You will definitely need new pistons (3.4 Camaro pistons or 3.4 TDC(DOHC) pistons) and 5.85" pushrods. You'll make at a minimum of 150 rwhp and up to 221 rwhp depending on your level of other mods you employ during the swap.
List of mods are as follows: Trueleo intake or stock ported TB to 57mm with upper intake DAWG mod and gasket matched porting and polishing ported and polished heads with exhaust ports opended up to 1 3/8" with Trueleo headers and a full 2.5" exhaust Or Sprint Manifolds with the stock Y pipe restriction removed on the crossover...
With Camaro pistons your compression ratio will be 9:1 ... with the DOHC pistons, depending on which gasket you choose you'll be at 9.8:1 or 9.965:1
GM rated 19# injectors will make it run slightly rich, 17# injectors will make it run slightly lean...without tuning. Ford 19# injectors act like GM 22# injectors and would need ECM tuning because that is way to rich without tuning as 18.2# injectors are just right...
I also recommend converting to the 88 alternator (if pre-88) and using Rodney's underdrive crank pulley which gained me 6hp and 8 ft*lbs on a dynojet dynometer.
There's about 5 or 6 people on the forum that I know of who maintained the Fiero top end and are quite happy. For a while I was using the Fiero ECM but had problems when I switched to the '7730 swap because my knock sensor wires and crank position sensor wires got too close to header and were resting against the block.
If you're running the Fiero ECM - it will work great. If you are also going to upgrade the ECM then you just got to take care and route everything properly.
You will definitely need new pistons (3.4 Camaro pistons or 3.4 TDC(DOHC) pistons) and 5.85" pushrods. You'll make at a minimum of 150 rwhp and up to 221 rwhp depending on your level of other mods you employ during the swap.
List of mods are as follows: Trueleo intake or stock ported TB to 57mm with upper intake DAWG mod and gasket matched porting and polishing ported and polished heads with exhaust ports opended up to 1 3/8" with Trueleo headers and a full 2.5" exhaust Or Sprint Manifolds with the stock Y pipe restriction removed on the crossover...
With Camaro pistons your compression ratio will be 9:1 ... with the DOHC pistons, depending on which gasket you choose you'll be at 9.8:1 or 9.965:1
GM rated 19# injectors will make it run slightly rich, 17# injectors will make it run slightly lean...without tuning. Ford 19# injectors act like GM 22# injectors and would need ECM tuning because that is way to rich without tuning as 18.2# injectors are just right...
I also recommend converting to the 88 alternator (if pre-88) and using Rodney's underdrive crank pulley which gained me 6hp and 8 ft*lbs on a dynojet dynometer.
Wow. My baby may be down for a while. where does one find the right pushrods?
[This message has been edited by Mr.Goodwrench (edited 03-25-2014).]
Trust me, they are quite familiar with the 5.85" length ($140).
Most of what you need to know is in the first few pages of my swap: https://www.fiero.nl/forum/Forum2/HTML/075502.html Includes links and part #'s. I chose to spend extra money on full roller rockers and the stud adapters to mount them but you can reuse the stock 1.6 roller rockers that come with the 3400...
[This message has been edited by lou_dias (edited 03-25-2014).]
Lou, how would the stock 3400 rockers work? How would they mount? This is the first time I've heard this.
I think someone posted in my thread that they did...I can't seem to find it in my inbox... I had to use adapters because my rockers were for a 3800 and used a 3/8" stud+nut... 3400 rockers are 1.6 ratio stock and roller fulcrum...
[This message has been edited by lou_dias (edited 03-26-2014).]
The 3400 as it was in the 05 Impala was 180HP... the F-body 3.4 was rated at 160. With just the stock Fiero intake setup and heads on top, and since it would then be so easy, the exhaust, you'll start towards the low end of that split due to the engine not being able to breathe enough to make use of it's better cam profile.
The 3400 is a cam, and maybe a 65mm LX5 throttlebody, away from 200bhp in its original configuration.
Really it's up to you how much you want to spend for how much power. Personally, I have a 3500 LX9 waiting to go into my car, mostly because all I really need to buy is a mild cam to get it to about 230 from it's stock 200bhp...
Lou makes the iron head setup sound very appealing, but look at the time and amount of money spent to reach the point he's at...
Have fun with your project. Regardless of what you decide to do, a Fiero with 150HP at the wheels is going to be about 30-35HP over what the stock 2.8 offers, and that is definitely an increase you'll feel.
The 3400 as it was in the 05 Impala was 180HP... the F-body 3.4 was rated at 160. With just the stock Fiero intake setup and heads on top, and since it would then be so easy, the exhaust, you'll start towards the low end of that split due to the engine not being able to breathe enough to make use of it's better cam profile.
The 3400 is a cam, and maybe a 65mm LX5 throttlebody, away from 200bhp in its original configuration.
Really it's up to you how much you want to spend for how much power. Personally, I have a 3500 LX9 waiting to go into my car, mostly because all I really need to buy is a mild cam to get it to about 230 from it's stock 200bhp...
Lou makes the iron head setup sound very appealing, but look at the time and amount of money spent to reach the point he's at...
Have fun with your project. Regardless of what you decide to do, a Fiero with 150HP at the wheels is going to be about 30-35HP over what the stock 2.8 offers, and that is definitely an increase you'll feel.
How much time did I spend?
My original build was done in weeks using the stock Fiero ECM and distributor, most of the time was waiting for the engine rebuilder to rebuild the block. Removing the old engine and installing the new is the same as stock other than grinding the pan, using the larger bolt on the cover and plugging the hole. 3400/3500 swaps that don't even involve a rebuild go on for months because you can't just hand off a "conversion swap" of a totally different motor to "Joe's garage" down the street like I did.
I've done a Camaro 3.4 swap with an HT260 cam and made 150 rwhp using the stock Fiero exhaust with Sprint manifolds and minor head and intake porting...that's why I set that # as the lower limit for this the Fiero top-end/3400 bottom end swap... The stock 3400 cam is better than the HT260...
PS, @carbon, I don't know if you caught on but my power levels have gone up since finding the bad CPS wires...no time to dyno yet since I've been moving. This explains why moving to the '7730 caused me to lose power over my 187/249 dyno using the Fiero ECM... No longer. ;-)
[This message has been edited by lou_dias (edited 03-26-2014).]
I personally have put a fiero top end on a 3100 block and used the 3100 pistons only bc I wanted to keep the stock look. It ran great. Everybody says compression is too low it won't run but it did. And it ran like a raped ape. It ran rich...but ran damn good. I also wired it up for a 7730 .. but with that said.. I have built a few 3400s and I can definitly tell you you have alot more options keeping the 3400 topend on it.. if I were to do another swap I would most definitly keep the 3400 together. U can use the factory lower motor mount and modify the top mount. And put a front mount alternator setup on like I did on mine. And just wire the 7730 to It and just change the connectors for the throttle body. And injectors. You will have to add the dis wires which is extremly easy. And add the knock sensor easy aswell. You can keep the fiero oil pressure sensor and relocat it to the oil filter housing. It has a port there.if you have any questions I and many others here will be more than willing to help you out.
Originally posted by kikinz24: Everybody says compression is too low it won't run but it did. And it ran like a raped ape.
No... putting iron heads on an 87-94 Gen II 2.8MPFI or 3.1MPFI will get you compression around 6.9:1 and it won't run, the pistons have too much dish because of the smaller combustion chambers of the Gen 2 aluminum heads. Although it may run, 7.9:1 compression with the 3100 pistons and iron heads will hardly yield an engine that will run like a 'raped ape'.
Edit: Without a turbo.
[This message has been edited by carbon (edited 03-26-2014).]
Originally posted by lou_dias: 3400/3500 swaps that don't even involve a rebuild go on for months because you can't just hand off a "conversion swap" of a totally different motor to "Joe's garage" down the street like I did.
I know, I know... swaps are easy when you can just whip out the checkbook. You always dismiss how much time has passed and how much money you've spent to get to where you are with your swap. Using the 3400 block and '7730 with DIS nets you the same swap issues as a full Gen III short of a dog bone or some other 4th mount solution. Using the stock Fiero ECM isn't a truly viable option as you've demonstrated.
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I don't know if you caught on but my power levels have gone up since finding the bad CPS wires...no time to dyno yet since I've been moving. This explains why moving to the '7730 caused me to lose power over my 187/249 dyno using the Fiero ECM... No longer. ;-)
Looking forward to seeing the results!
[This message has been edited by carbon (edited 03-26-2014).]
The only reason I see full 3400/3500 swaps taking a little longer then the 1/2 breed iron head swaps is that most of the full swaps go further then just a stock engine. if I had used a stock 4 speed and a stock 3500, the only hangup would have been the exhaust, and even that would have been easy enough to sort out. the aluminum heads are proven to perform, they can and will outperform the iron heads engines. don't just look at peak numbers, they're pretty much useless for anything more than bragging rights, look at the area under the curve and how flat the torque curve is, that's what makes a fast car, consistent, predictable car, with good street manners.
Cylinder head technology has come a long way over the past 30+years, ports, chambers, valvesprings, castings and materials ect. the only thing the iron heads offer that the aluminum heads can't currently do better is a stock appearance, but a well thought out aluminum head swap can look right at home under a fiero's decklid.
To get my 3400 in and running/drivable with changing out the intake gaskets took me a month. Working weekends and the odd evening. I did modifications to many other areas of the car at the time which took much longer. If I were to do a 3400 swap straight up, with just the intention of getting the engine in and running, I could probably do it in a weekend, two for sure.
To get my 3400 in and running/drivable with changing out the intake gaskets took me a month. Working weekends and the odd evening. I did modifications to many other areas of the car at the time which took much longer. If I were to do a 3400 swap straight up, with just the intention of getting the engine in and running, I could probably do it in a weekend, two for sure.
I agree 100%, and the intake leaks, 3800's had similar problems too, both are corrected with a new gasket design. with the engine out of the car, this job is easy as pie.
I agree 100%, and the intake leaks, 3800's had similar problems too, both are corrected with a new gasket design. with the engine out of the car, this job is easy as pie.
Agreed to that. I bought a valve spring tool allows you to lift the rocker to get the pushrods out . I can do a complete intake gasket set in a car in about 2.5 hrs. Out of a car a hour.
People bash 3400s but honestly theyre a good motor. I would definitly use one for a quick affordable swap. Beings you dont have much to modify on it to make it work.
Intake leaks... look up intake leaks over at LS1tech.com... no GM engine is immune to GM engineers.
I hate engineers, especially automotive engineers, between them and the bean counters they have this love hate relationship that turns my stomach.
don't get me wrong they have made some great strides in engine performance over the last decade, its a shame it took them 20 years but they have done great things over the last few years. I would love to rebuild Reba, Amanda my youngest who is the real owner of our Fiero, long story and she named the Fiero.
But I would rather it look stock under the hood, meaning the original Fiero intake on top, even if it meant porting and polishing the intake and exhaust. that I could do or have done by some friends I know local, one owns a machine shop and the other a repair shop who both owe me favors or would charge me minimal amounts for work they would do. Which is a good thing seeing I am on a fixed income now that I am disabled. but do have friends who are helpful when it comes to things like this, we help each other out when we can.
great thread by the way and don't let me derail it.
edit to add
I found this site on the idiot net that may be of some help, to me anyway
I found that site back when I first got my Fiero back in April of 2004... and it looks like they haven't updated it once since then, other than to remove all pricing information and add the 'contact us' links for everything.
Originally posted by carbon: Swaps are easy when you can just whip out the checkbook. You always dismiss how much time has passed and how much money you've spent to get to where you are with your swap.
Have to agree on this, for me a swap is about doing it myself, would defeat the purpose to have a shop perform the swap for me.
My aluminum head 3500 + 7730 swap took about 5 months to complete (although I am still working on the tune). But then again, this was my first engine swap of any kind, and I had limited fabrication experience.
I also took longer because I kept my Fiero timing cover and accessory drive. If done again, I would keep the FWD accessory drive. It's cleaner, less work, and more reliable.
Not to say that the iron head 3400 is a bad idea. Keeping the stock look is appealing. Likewise, it looks like you've chosen the 3.4 PR iron head swap from the Camaro which is probably the easiest engine swap you can do. I would probably replace the cam though - the 3.4 PR have a flat tappet cam like the 2.8 Fiero motor does and they do wear down with time. V6 Camaro owners aren't known for their maintenance practices either. The cam is probably well worn by now.
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Originally posted by Raydar:
I just bought a G6 with a 3.5. I love that engine. 220 HP right out of the box. My next Fiero swap will likely be a VVT 3.5. Or maybe a 3.9.
I'm curious how much harder the LZ4/LZ9 motors are compared to the LX9. Based on driving a 06 G6 and a 07 G6, the former with the LX9/3500 and the latter with the LZ4/ 3.5 VVT, the 3.5 VVT is much, MUCH smoother and sounds much more like a multi-valve engine.
[This message has been edited by masospaghetti (edited 03-28-2014).]
You always dismiss how much time has passed and how much money you've spent to get to where you are with your swap. 
Using the 3400 block and '7730 with DIS nets you the same swap issues as a full Gen III short of a dog bone or some other 4th mount solution. Using the stock Fiero ECM isn't a truly viable option as you've demonstrated.
