Chevy 3.6 v6 engine swap (Page 1/3)
Cajun DEC 22, 09:21 AM
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.
hyperv6 DEC 22, 09:54 AM
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.

hyperv6 DEC 22, 09:57 AM
Might want to look at a Impala 3.6 FWD. it is the older model but closest to what you would be doing in a Fiero install.
Cajun DEC 25, 09:03 AM
Thanks for the comments everyone.

I am still interested in this swap. So I guess additional research is needed!
Daryl M DEC 27, 08:52 PM

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).]

Dennis LaGrua DEC 31, 09:13 AM
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.
hyperv6 DEC 31, 09:30 AM
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.
Cajun JAN 10, 09:43 AM
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.
msweldon JAN 10, 04:23 PM
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).]

Will JAN 10, 08:06 PM

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.