3900 Swap? - Newbies Forum

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3900 Swap?
Friday, March 30, 2018 12:54 AM
I'm sure I missed the answer somewhere between the Newbies FAQ and the V6 Swap page, but will the 60-degree 3900 from the Malibu SS fit in my '98 GT? I know 240 shouldn't be too hard to get the 2.4 to make, especially with a turbo, but I'd rather the experience of doing a motor swap over the simplicity of a turbo install. I saw posts talking about the 3100, 3400, 3500, and 3800 engines, but nothing about the 3900. I also saw on the Newbies forum that my trans is an Isuzu, not either Getrag. How can I verify that, because somewhere else I thought I saw that it had the same Getrag F23 that the Olds Alero and Pontiac Grand Am have paired to their LD9? If the 3900 won't fit, then my next choice will be either the 3500 or the 3400. Do the 4t40 and 4t45 (the autos paired with the 4-cylinder vs v6 engines in said Olds & Pontiac) have different bolt patterns?

Now that my Sunfire is running and I've had time to drive it more, I hope to be more certain with what I want it to become than while it was out of commission and I was him-hawing around. I have upgrade ideas for the interior, including a pioneer radio w/ speakers, seat covers, and floor mats. I have some ideas for the exterior, including a (Saleen) spoiler, window blinds, and some HIDs. As I get the parts and either need advice installing them or want to show off the progress, I'll pop in and post.

Re: 3900 Swap?
Friday, March 30, 2018 12:30 PM
No idea about the swap, sorry.
However, I do know that the 4 cyl and 6 cyl transmissions are different and will not interchange. If you plan to put a 6 cyl engine in the car, you will need a transmission from a 6 cylinder, be it a manual or an automatic.
Re: 3900 Swap?
Friday, March 30, 2018 1:00 PM
It has been said many times on this forum that the LN2 and the 60* V-6s share the same bellhousing.





Re: 3900 Swap?
Friday, March 30, 2018 9:15 PM
Ok. Were the LN2 and the LD9 paired to the same manual trans? Sorry, the difference between the 3rd-gen Isuzu J's and the 3rd-gen Getrag J's is confusing me. One spot says all manuals in certain model years were one or the other, another says it varied by which 4-cylinder.
Re: 3900 Swap?
Saturday, March 31, 2018 2:14 AM
I was mistaken about the bolt patterns for the 4 cyl engines. I think that it is the transmission for the quad 4 that will not bolt up to a v6, where as I suppose the other 4 cyl ones will (?). Anyway, as I understand it, you really wouldn't want a quad 4 trans on a v6 anyway, since 1st gear would be nearly useless, unless you were wanting to pull tree stumps out of the ground.

Another thing to take into consideration would be the strength of the trans. Some of the 4 cyl trans were not as tough as others. Most guys putting in 3400 or turbo/superchargers are using the Getrag 5 speed. These were the toughest of the lot. The Isuzu trans is not recommended as it is a light duty design. Now I'm talking about what is common in a 2nd gen swap. I really don't know anything about the 3rd gen cars. I think I've only rode in 1 in my life. Anyway, I'd suggest using a Getrag HM282. The NVG T550 is also beefy enough for a lot of torque, so that would be another option.

Another thing to consider would be the final drive ratio. The v6 is a lower reving engine with a powerband that's also lower than that of the 4cyl engines. With a low final drive you'll be turning more rpm's in normal cruising and outside of the engines 'sweet spot' for highway mileage.
Re: 3900 Swap?
Saturday, March 31, 2018 9:25 AM
Ok. I don't understand as much about highway mileage 'sweet spots' as I should. I know MPG basically comes down to the lower the RPMs, the less fuel being burned. I'm not sure how it converts to a comparison with the LD9 powerband, but the LZ9 (High Value 3900) claims to have full power between 1500 and 5500 RPMs.

Which 3400 is usually the one being put in? The LA1 (60-Degree 3400 V6) from the late-90s/early-00s GM minivans and Pontiac Grand Ams, right? As much as it's ~70 HP short of the LZ9, if the 3900 just is completely unreasonable, I can tell the 3400 is good candidate. Presumably the LX9 (High Value 3500) is as well, since that link leads me to believe it's a newer year version of the LA1.

The Getrag swap reads as relatively straightforward. Mounts and maybe (hopefully not) an adapter plate. Will a stand-alone ECU allow the gauges to still work correctly? I'm not too fond of the still tach in the youtube videos claiming to be a v6 sunfire.
Re: 3900 Swap?
Saturday, March 31, 2018 3:24 PM
I read a little about the LZ9. It has variable valve timing, and will disable a bank of cylinders. That will help compensate for the lower geared 4cyl transmissions. Not that it will really lower the rpm at a given speed, but should help to reduce fuel consumption.

As for the 3400, seems that whatever they find in good shape is used, not any certain one in particular, that I've noticed. However, the ones from vans have slightly more HP. Only like 5 or so, I think it is, but hey, why not.

No idea about a stand alone ECU working everything correctly. I'm sure it is possible, but no idea how involved it is to get everything working. I'll admit, I don't know much about OBD2.

Good luck with your project.
Re: 3900 Swap?
Monday, April 09, 2018 1:13 PM
Jeffrey Womack wrote:

Ok. I don't understand as much about highway mileage 'sweet spots' as I should. I know MPG basically comes down to the lower the RPMs, the less fuel being burned. I'm not sure how it converts to a comparison with the LD9 powerband, but the LZ9 (High Value 3900) claims to have full power between 1500 and 5500 RPMs.

Which 3400 is usually the one being put in? The LA1 (60-Degree 3400 V6) from the late-90s/early-00s GM minivans and Pontiac Grand Ams, right? As much as it's ~70 HP short of the LZ9, if the 3900 just is completely unreasonable, I can tell the 3400 is good candidate. Presumably the LX9 (High Value 3500) is as well, since that link leads me to believe it's a newer year version of the LA1.

The Getrag swap reads as relatively straightforward. Mounts and maybe (hopefully not) an adapter plate. Will a stand-alone ECU allow the gauges to still work correctly? I'm not too fond of the still tach in the youtube videos claiming to be a v6 sunfire.
Either the LZ4 or LZ9 could be made to work, but the question is, how much work do you want to do for it to work right? A stand-alone ECM will not make the gauges work correctly.

The LA1 and LX9 both work great with the 02-04 Impala ECM flash on a manual transmission in an 02-05 J-body (no adapter plate needed, just get the Getrag from the 2200). It's a very tried-and-true swap at this point. If you want the experience of doing a motor swap, but don't want to have to get deep into problem solving with it, I would go with one of those. They have a ton of potential, and you can easily hit the power number of the LZ9 with minimal mods and tuning. I also still sell the upper motor mount that will make a 3400 pretty much bolt-in, and you can use the RK Sport urethane insert with it.





Re: 3900 Swap?
Monday, April 09, 2018 1:20 PM
I just reazlized that you're doing the swap into a 98. I would recommend converting your wiring and dash over to 00+ for this swap.





Re: 3900 Swap?
Thursday, May 03, 2018 3:33 PM
Ok. I'll look at the wiring/dash conversion. The LX9 was the engine in my first car, an '05 Malibu LS V6, so that's probably the one I'll go with between the LA1 and LX9. Out of curiosity, how is best for finding F23s online? I'm only finding parts when I just google its product code. Is one of the host vehicles easier to find the transmission from than the others? In case I have as much trouble finding the 3.5 as I've had looking for the 3.9, how have you guys found is the easiest way to find good condition components?
Re: 3900 Swap?
Friday, June 08, 2018 9:01 PM
If I'm going to want to swap to the '00+ wiring harness anyways, I may as well go with the more tried-and-true power increase of just boosting the LD9. I'll be back when I run into problems I can't find an answer to elsewhere.

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