I have seen several post regarding the 3.6 Chevy v6 swap. What I have not really seen is any post indicating that anyone has actually successfully completed this particular engine swap.

I am planning an engine swap in the near future and very interested in the 3.6 V6 engine as a swap candidate. I have noticed those engine are beginning to show up in numbers at the local Pull-a-Part.

Well here is the deal.

The old version of the engine has timing chain and carbon issues.

The later version they are fixed. It is a much different engine.


Even with it being a 60 degree engine odds are it would be a tight fit. They also are not light.

Another factor is they have power only under higher RPM. You really have to learn to drive them different vs a V8. You need to drive it harder for the power as it really starts at 3000 RPM.

I have three of these engines in other vehicles. I have been happy with them. The early one does use a little oil but nothing serious. The two later engines are totally problem free.

While it would look good in the engine compartment I would still go with an LS engine swap. Just more parts and more compact. They are cheap now too with so many trucks with them.

To do a 3.6 you are going to be left with mostly your own engineering and a lot of extra work. The later V6 has the exhaust manifolds cast to the heads. That is good for space but not if you want to route them else where if you have a need.

If you chose to do this I would love to see it. I love this engine in my Acadia and Canyon but it is not my first choice for the Fiero.

The LNF 2.0 would be my choice if I were to take on a swap challenge. That engine is just crazy powerful on the GM performance tune. It turned my HHR into a 13sec car. That is if you could get the tires to hook up. It really needed a RWD application. FWD hated 23 pounds of boost.

Thanks for the comments everyone.

I am still interested in this swap. So I guess additional research is needed!

quote Originally posted by Cajun: Thanks for the comments everyone. I am still interested in this swap. So I guess additional research is needed!

This may be of interest

http://www.fiero.nl/forum/Forum2/HTML/142132.html

[This message has been edited by Daryl M (edited 12-27-2020).]

I believe that you are talking about the GM LFX/LGX engines. They are high tech engines and put out up to 323 HP (LGX ) but as hyperv6 said you've got to get high up in the RPM range to develop that power. Actually the power ratings are at 6800 RPM. Those engines are big and bulky. They have been swapped but not in a driveable Fiero so far. This engine looks to be a tight difficult swap in a Fiero but with enough work and engineering I guess anything is possible.

Just to clarify the engine makes power on a steady line in the RPM range. Torque is more felt just below 3000 rpm to just over 5000 RPM.

You need to get the revs up to feel the pull unlike 2 valve V8 that has more low end torque.

The engine runs and drives well but you have to adjust to how it drives. The power is there you just drive it different.

I love my Canyon with the later version.

The key is to avoid the early models for the later. It is a much different and better engine.

I would still do the LS in all aluminum. Cleaner, simpler and more power. May even be cheaper since they are more common.

After some careful consideration I am inclined to favor the 3.6 v6 swap! I hear and understand the arguments suggesting doing the LS4 swap. In my mind both swaps are difficult, time consuming and even costly. The reason I am favoring the 3.6 v6 swap is simply due to the fact they are not common in the Fiero where as the LS4 is.

In my neck of the woods the 3.6 v6 engine is plentiful in the local Pull-a-Part where as not so much the LS4. Besides, I have several cradles so working on the swap will not impact driving my 86Gt. For test fitting I do have a donor 87Gt. Again work can progress while not impacting my 86.

I will be using Daryl M's thread and more than likely picking his brain to help me alone with the swap. Metal fabrication will not be an issue as my son owns a fabrication shop with both CNC Laser & Plasma cutters. A big plus!

Thank you all with your comments and specially to Daryl M for providing a link to his build.

As someone else who is swapping in a 3.6 variety engine, I went through many of the same questions you did.

If you go V6 go with the LFX 3.6, it has most all the mechanical bugs worked out but without DOD and other GM efficiency electronics of the LGX.

As plentiful and powerful as the 3.6 is...and it is powerful.. they make almost full torque by 2000-2500rpms and maintain it out past the hp peak with the DI and VVT technologies......just overlay the Gen1.5 Acura NSX dyno with that of a tuned LFX... they are almost the same with the LFX making more horsepower and torque and without revving out to 8K. Having said that it "is" GM's disposable workhorse engine they throw into everything with little aftermarket support... much like the 2.8-3.4 60deg V6s of the 80s and 90s.

Your power will be limited in the 3.6 to tunes and expensive cams for not 'that' much more power. The 3.6 cannot take much boost as it was designed to be the 'most' you could pull out of a N/A engine with VVT and DI. Unless you go full rebuild or LP9/LF3/LF4/LAU but then $$$$$, I know.....

You are limited to the factory ECU due to the DI setup unless you pay big $$$$ for a Motec... but given the complexity and engineering GM put into the maps with VVT and DI no real reason to abandon them.

You will have to deal with 'two' fuel pumps, the in-tank one and the mechanical High Pressure one... your in tank fuel pump will have to support PWM plus greater output.

Be careful which 3.6 you grab... some have the Fuel Pressure Control Module integrated into the BCM and some separate. Go with the separate.

The miata and RX8 crowd have been swapping out LFX's for a few years and can be utilized for knowledge as well.

You have a quick axle solution with the cobalt axles but you have to offset the engine 2" toward the PS. If you are going to rail on the engine, the cobalt SS axles are probably not going to hold up... then its custom.

Your transmission is limited to the auto that comes with the 3.6 if transverse or running a Saab 9-3 F40 setup. Mender on the board here has adapted an F23 to the 3.6 with a fair amount of bracketry.

If you are dead set on a 3.6 but also will want more power, do take a gander at the LP9 out of the Saab 9-3 Aero or 2010-2011 Cadillac SRX. It is the same block as the 3.6's but 2.8L (can be bored / stroked) but with no DI or VVTi, 280hp stock with a vicious torque curve and you have all the go fast turbo bits internally and included for upgrading. The only downside is the bosch ecu in the earlier saab 9-3's but I 'think' this has been dealt with in the saab community. The cadillac SRX's aren't known to have this option by many so you can get a mildly driven 'caddy' driven one of these.

The LS4, although is a bastard child of the LS family, it still is a relative which has large amount of aftermarket support...LARGE.... so thereby inherits some of this...don't EVER underestimate aftermarket support..

The LS4 is compact height-wise but is still a V8 when it comes to width. The 3.6's are narrower but a fair amount taller due to the DOHC heads, not quite LQ1 large though. You will have a 'tight' fit between the towers with an LS4... The 3.6s being very tight against the firewalls.

The LS4 with cross GM LS modifications/parts, see FieroGuru, will give you ~340whp... that's NA wheel horsepower with only a mild cam and great torque curve.... that is damn impressive with the simplicity of no VVT or DI.. A valve train upgrade on the LS4 will allow it to rev to 7000. The 3.6 with all the NA goodies available.. i.e. $$$ can barely break into the 300whp range and you have to rev it out with those mods... ultimately an engine is an air-pump.... the LS4 will always win out as it simply has more displacement with just as solid engineering as the 3.6 V6s.

The LS4 has the same custom axle issues as the 3.6s more or less.

Factory GM ECU or any aftermarket ECU can drive the LS4.

Mounting-wise the 3.6 fits relatively well between the front and rear cradle rails while the LS4 can require modifications.

Both will require custom mounts throughout with pre-made LS4 ones available through WestCoastFiero.... ymmv though..

My personal thoughts....... if you enjoy winding out your engines a little more go with the LFX 3.6.. it's like a more complex more mature LQ1. If you enjoy the sound and early torque of a V8 go LS4. Both would be quite drivable and enjoyable in stock or mildly modified forms.

My aggregate research results in terms of hp goals vs cost between the LS4 and the 3.6 HPV6s:
250-300 - LFX (shear availability and generally lower mileage availability in yards)
300-400 - LS4
400-550 - LS4 or LF3/LF4
600+ - LS4 (this is where the LS aftermarket really comes into play)

Last thought... the 3.6's sound like crap..nothing like the 60deg V6's of the 80s and 90s and I don't know why yet... I've only heard a couple of decent sounding 3.6's a Camaro LFX with a Borla and an ATS-V with Borla... The LS4 well........because V8... if only they made a flat plane 4.8L destroked crank for it...

[This message has been edited by msweldon (edited 01-10-2021).]

quote Originally posted by Dennis LaGrua: I believe that you are talking about the GM LFX/LGX engines. They are high tech engines and put out up to 323 HP (LGX ) but as hyperv6 said you've got to get high up in the RPM range to develop that power. Actually the power ratings are at 6800 RPM. Those engines are big and bulky. They have been swapped but not in a driveable Fiero so far. This engine looks to be a tight difficult swap in a Fiero but with enough work and engineering I guess anything is possible.

They all have dual cam VVT, and the ones worth swapping have DI and high compression. They have plenty of low RPM torque.

They're a little more compact than the 3.4 TDC, so they fit the engine bay just fine.

msweldon & Will, thank you for your comments and feed back.

msweldon, not sure I full understand this comment...
You have a quick axle solution with the cobalt axles but you have to offset the engine 2" toward the PS. If you are going to rail on the engine, the cobalt SS axles are probably not going to hold up... then its custom

What is your suggestion on which engine would be the best candidate for a swap? Current I am considering either a 2011 or 2012 Chevy Impala 3.6. Oh, my transmission of choice would be an automatic.

Again, thanks for the comments.

quote Originally posted by Cajun: msweldon & Will, thank you for your comments and feed back. msweldon, not sure I full understand this comment... You have a quick axle solution with the cobalt axles but you have to offset the engine 2" toward the PS. If you are going to rail on the engine, the cobalt SS axles are probably not going to hold up... then its custom What is your suggestion on which engine would be the best candidate for a swap? Current I am considering either a 2011 or 2012 Chevy Impala 3.6. Oh, my transmission of choice would be an automatic. Again, thanks for the comments.

No problem... if you shift the engine transmission mating point 2" to the passenger side using the F40 Transmission the Cobalt SS axles will bolt right into a Fiero. The downside is that the cobalt axles are prone to failure under higher hp or high acceleration stresses. So much so Chevy redesigned the axles and used beefier hubs from the Pontiac G6 and equivalent platforms.

You're going auto, either 6T70 or 6T75 depending on what you choose as your donor, so I'm not sure 'if' those axles would work as I'm only familiar with the F40 thus far.

As far as a donor goes, the impala like Daryl went with is a good choice as the wiring harness lines up nicely with the fiero positioning-wise, but that's it. All the circa ~2012 LFX's are right around 300hp with the Camaro's having the most by about 10hp. Whether or not its due to the tune or intake or both, I don't know. You 'could' slap on the Camaro intake to an impala LFX to find out. The Impala is a fine choice with the 6T70 6spd auto but the Acadia/Enclave/Traverse/XTS w/ LFX have the 6T75 which is a bit more stout. If you ever decided to go crazy with the LFX i.e. turbo, supercharge, nitrous, what have you... you could upgrade to the 6T80 theoretically.

As far as fitment goes.. the alternator and power steering pump(if you even plan on running power steering) can be swapped to either side of the engine with the appropriate brackets... as a matter of fact, if you go impala I recommend getting the Camaro alternator bracket and relocating it to the left side of the engine where the fiero alternator sits.. that frees up a lot of firewall room near the decklid brackets...

Honestly whether or not it controls the in tank fuel pump via BCM or FPCM pull whatever is necessary including as much of the harness, TCU, battery charging monitor, all fuse/relay boxes, fuel pumps, sensors, emission components, engine, ecu... Even if you don't want the Impala gauges, for example, pull them and use them to get underway.. then figure out how you want to handle the canbus signals to run the fiero gauges, aftermarket gauges etc.. What units you don't use, you can ebay, what harnesses you don't use, you will use the wire and bulkhead connectors elsewhere... If I were you I'd find a pick and pull and spend several days gutting it or purchase a wreck delivered to your house and gut it there then have it hauled off.... tracking down all the bits, connectors, and sensors to make the ECU happy has given me my first gray hairs..

Hope this helps...

Cobalt SS axles as well the HHR SS will take 315 ft lbs easily. The GM tune for the Turbo model was set to this level by GM.

I never had an axle issue in my SS.

msweldon,

Thanks for the feedback and information.

quote Originally posted by hyperv6: Cobalt SS axles as well the HHR SS will take 315 ft lbs easily. The GM tune for the Turbo model was set to this level by GM. I never had an axle issue in my SS.

Additional specificity needed on my part. The 1st Gen cv axles on the supercharged Cobalt SS with the LSJ have experienced numerous failures. This is from what I've read on multiple Cobalt threads, it may be due only to drag racing with wheel hop and engine mount positioning, I don't know which but realized that they were not going to be enough to hold the torque my installed setup will be putting down, especially chicom manufactured ones. The LSJ axles are the ones that can bolt directly into an F40/F35 on the inboard side and into the Fiero uprights on the outboard ends. The failures were so prevalent GM reconfigured the CVs and uprights from larger GM platforms for the LNF Cobalt SS.

The turbo LNF axles are a different beast altogether, different outboard stubs and much thicker axle shafts. I utilized the LNF axles in my swap by replining the outboard shaft to fit a G6 cage then put my fiero stubs onto them. Hindsight being 20/20 I would have played around with some saab 9-3 / 9-5 axles or had a custom axle shop recreate the LNF axle shafts, splined correctly for the fiero outboard and 2" shorter for one and 2" longer for the other. If these fail I'll head over to DSS for their beefed up LSJ axles.

This all may be moot for Cajun as he's going 6T70/6T75

[This message has been edited by msweldon (edited 01-11-2021).]

quote Originally posted by msweldon: The Impala is a fine choice with the 6T70 6spd auto but the Acadia/Enclave/Traverse/XTS w/ LFX have the 6T75 which is a bit more stout. If you ever decided to go crazy with the LFX i.e. turbo, supercharge, nitrous, what have you... you could upgrade to the 6T80 theoretically.

FYI, there is no 6T80E

quote Originally posted by Will: FYI, there is no 6T80E

https://gmauthority.com/blo...m-transmissions/mhm/

The 6T80 comes on the XTS-V

[This message has been edited by msweldon (edited 01-11-2021).]

I have no plans of boosting the engine of other mods to increase hp. All I am looking for is a reliable engine and transmission that will bring my GT newer technology and horsepower.

I am hoping this will be the last of the upgrades for the vehicle.

quote Originally posted by Cajun: I am hoping this will be the last of the upgrades for the vehicle.

Said every fiero owner ever.....

quote Originally posted by msweldon: https://gmauthority.com/blo...m-transmissions/mhm/ The 6T80 comes on the XTS-V

Interesting... I googled 6T80E, but I guess the E is no longer necessary

Don't know what else could be done to the car? I've had the GT since 1992 and have done the following mods:
1. Relocated battery to the front
2. Installed Lambo doors
3. 3.4 engine -95 Firebird
4. 4T60 auto transmission
5. Grand Am front brake upgrade
6. Big brake booster upgrade
7. 2001 Grand Prix digital HVAC controller & display
8. 2002 Firebird BCM, this gives me RAP, auto door locks, etc.
9. DIN 1 radio, GPS
10. LED lights all around
11. Custom rear light panel (Corvette style)
12. Currently working on installing a 92 Riviera digital instrument cluster
13. Mr. Mike's seat covers

Think I'm kinda maxed out!

Oh, planning on an engine swap, Chevy 3.6 plus 6-speed auto transmission

[This message has been edited by Cajun (edited 01-15-2021).]