3.5 engine swap question (Page 1/2)
Yorgle SEP 05, 10:29 AM
I have a chance to get a low-mile 3.5 and automatic transmission from a 2005 Impala for very little cash and was thinking about using it as a replacement for the Duke in my 86. It seems all of the3.5 swap info I've read relates to 3.5's sourced from Firebirds and Camaros. I assume that I'll need to modify axles, mounts and brackets and use the Impala ECU and probably a stand-alone controller for the transmission. But is there any deal breaker with this engine that I've overlooked?
Vintage-Nut SEP 05, 10:44 AM
Do You Search '3.5' or '3500' ?

http://www.fierosearch.com/...5%20&Action=DoSearch

http://www.fierosearch.com/...3500&Action=DoSearch

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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

Dennis LaGrua SEP 05, 10:52 AM
The GM high value engine swap has been done before but I don't know how many exist in Fiero's. If you look on You Tube you will find many swaps with this engine. While I have not done this swap it looks like many changes need to be done before this swap can be completed.( its a drive by wire engine). The good news is that some versions of this engine put out as much as 242 horsepower. If you use the engine with the GM auto transmission the OEM PCM should be able to handle the job but using it without the BCM and CANBUS inputs may prove tricky. The swaps that I have seen use aftermarket ECM's with cable operated throttle bodies.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 09-05-2024).]

Raydar SEP 05, 05:58 PM
Are you sure it's a 3.5? I don't see it listed for the Impala. If you have access to the RPO sticker (probably inside the glove box or console) look for LX9.
If there's a different "L" code, please let us know.

If it's an LX9, it's been done a bunch of times. You can use the donor PCM or a different one.

If it's an LZ4 (which didn't happen until 2006) then there's a whole 'nother can of worms to deal with. The LZ4/LZE/LZ9 motors were VVT.

None of these motors really have anything in common with the 3.4 Camarobird motors. Those motors had iron heads, and are fairly limited.

https://en.wikipedia.org/wiki/GM_High_Value_engine
https://en.wikipedia.org/wi...s_60%C2%B0_V6_engine

[This message has been edited by Raydar (edited 09-05-2024).]

82-T/A [At Work] SEP 06, 09:06 AM
I just wanted to add... if it's the 3500 we're talking about, it's a FANTASTIC engine. It will bolt up to your stock transmission, and will bolt up to the factory engine mount location (from what I understand). Everything else you'll need to use from the donor car... like all the accessories, exhaust manifolds, computer, etc. You'll need to fabricate a Y-pipe.

But if you can get it in there, the 3500 is one of the smoothest / nicest engines in my personal opinion. It's really an improved version of our old V6/60s.
Yorgle SEP 06, 12:36 PM
I talked to the seller and it's actually a 3.4 NOT 3.5. Here's a link to the facebook ad: https://www.facebook.com/ma...05a-73101d35b3e1With that being the case, would it nevertheless be a good candidate for a swap? My thinking is that it would be an inexpensive way to get a reliable runner, a 4 speed overdrive transmission AND nearly double the horsepower of the duke.

[This message has been edited by Yorgle (edited 09-06-2024).]

82-T/A [At Work] SEP 06, 01:41 PM

quote
Originally posted by Yorgle:

I talked to the seller and it's actually a 3.4 NOT 3.5. Here's a link to the facebook ad: https://www.facebook.com/ma...05a-73101d35b3e1With that being the case, would it nevertheless be a good candidate for a swap? My thinking is that it would be an inexpensive way to get a reliable runner, a 4 speed overdrive transmission AND nearly double the horsepower of the duke.




Ok, so that's the 3400 SFI, basically the exact same thing as the 3500, just .1 liters smaller (which is basically insignificant. The 3400 SFI motor was commonly found in the Pontiac Grand Am GT in the early 2000s, and it's a fantastic motor. Like, the ONLY reason why I'm not going this direction in my Fiero, is because I want my Fiero's engine bay to look as stock as possible... so I went the more expensive route of going with a 3.4 Camaro / Firebird block, and re-using all the factory Fiero components (which produce quite a bit less horsepower than what you have).

For the most part, everything you need is there. There's just a few things you're going to have to deal with:

1 - You don't have an ECM. So you'll want to get an orignial engine harness (the one on this motor seems to have been cut), and get an ECM from an appropriate year car. In my opinion, you'll want to keep the factory ECM because it will allow you to take advantage of Sequential Port Fuel Injection, rather than Multi-Port Fuel Injection, which produces better performance and efficiency in the lower rpms (no difference over MPFI in the upper rpms).

2 - You will need to remove the power steering pump, and either install a bypass or get a shorter belt. You will probably also want to relocate the alternator further down, and can probably re-use the Fiero's alternator brackets (maybe).

3 - You'll need to fabricate an exhaust Y-pipe

4 - If you plan to use the 4-Speed automatic that's in there (4T60E), you'll want to follow this: https://www.pontiacperforma...s/4_Speed_Swap.html. If you have an 85-87, then there is no modification necessary... just need new mounts / brackets.


Finally, with 102k miles, it's probably a solid engine; however, you already have the motor out, and in my opinion, it would be worthwhile giving it a once-over. Depending how comfortable you are in refreshing it, I would replace the crank and rod bearings since you'll have access to it, and replace the head gaskets and all the other gaskets as well... and probably even replace (or have cleaned) the injectors. But other than that, it's a really nice motor.

It's an LA1: https://en.wikipedia.org/wi...%C2%B0_V6_engine#LA1

Looks like it's the 175hp / 205ft-lbs version... which is nothing to sneeze at. The Camaro / Firebird motor is stock 160hp. In the Fiero, with a shorter exhaust, you're probably looking at 180hp without doing any modifications.


Honestly, there's a few people that have these blocks in their cars, and there's several modifications, including a better cam that you can install, which should easily get you up over 200hp. Part of me wishes I went this way, I just really want to keep my Fiero looking stock, which is why I went with the Firebird Gen-1 3.4 engine.

[This message has been edited by 82-T/A [At Work] (edited 09-06-2024).]

richard in nc SEP 06, 06:33 PM
[
4 - If you plan to use the 4-Speed automatic that's in there (4T60E), you'll want to follow this: https://www.pontiacperforma...s/4_Speed_Swap.html. If you have an 85-87, then there is no modification necessary... just need new mounts / brackets.


that link doesn't work for me,
82-T/A [At Work] SEP 06, 06:40 PM

quote
Originally posted by richard in nc:

that link doesn't work for me,




Thanks, fixed it. It "consumed" the period at the end, and made it part of the link, which then invalidated it. I corrected it up above... but here it is again:

https://www.pontiacperforma...es/4_Speed_Swap.html
Yorgle SEP 09, 10:54 AM
Again, thanks for all of the great info- I pulled the trigger and bought the motor and it's now sitting in my garage. Unless the forum moderator can fix the title to this thread, I think I'll start a new thread from here on out since this is actually a 3400 and not a 3.5.