LV3 Engine Swap (Page 2/2)
DimeMachine DEC 30, 08:28 PM

quote
Originally posted by fieroguru:

If I was going to do a V6, it would be the LV3.

I swapped a 1992 4.3 CPI engine with the 4T60 in an 88 back in 2007ish and drove it daily until about 2011. I really liked the engine, hated the auto. It had plenty of power and torque to be fun, but not so far over the top where I couldn't drive it in the snow. As for why I didn't just do a SBC... I already had a SBC fiero and really didn't need two of them. The shorter length really made the swap easier than doing a SBC.

I have had a LS4/F40 with 382 whp since 2013 and 55K miles and really love the LS platform, but GM never made a 3/4 LS and stuck with the SBC variant until the LT/Ecotec3 series engines were developed. If I ever get to having a 2nd FIero, I would love to swap in the LV3 with the F40. Back in 2015, there was a link to GM offering the LV3 as a crate engine for marine application and it also had the controller package, so I doubt there will be any unsurmountable issues, but it will definately be some uncharted territory.

You will have to:
Cut the starter mount pad off the engine to clear the 4T60/440-T4
Use an adapter plate to bolt the engine to the transmission (Street Dreams SBC one would be good to start with, but will need modified).
Use 142 tooth flex plate to fit inside the bellhousing (Lt engines only come with 168 tooth flex plates, and I think they all run the 8 bolt pattern on the crankshaft so you can't use the LS4 flex plate).
Create some spacers and crank support for the torque converter to take up the extra space from the adapter plate.
Figure out a starter solution - my LS4 starter solution could likely be adapted to work.
The rear exhaust manifold probably won't clear the auto, but you might be able to use two front (or driver side) manifolds (that is what I did for my 4.3 CPI swap).
The oil pan will likely need to be trimmed down to let the engine sit nice and low in the engine bay.
A/C compressor is right where the passenger axle needs to be, so it will have to be removed or relocated - so some accessory rework will be needed.
The 4T60/440-T4 can use stock GM mounts (probably wouldn't want to based on your power goals) and stock GM axles.

From there it is just a matter of plumbing, wiring, and ecm. The water pump is nice for the FIero layout




Good Solid info. I appreciate your posts!
cvxjet DEC 30, 09:48 PM
That engine is (Approx') 70 lbs lighter than the 2.8 V6.....Which will actually improve the handling a bit (You want 45/55 to 47/53 weight distribution for best handling (Like the original Boxster/Cayman- They compensate for worse distribution on later versions (And 911s) by having extremely fancy suspension geometry)

Since that engine came out I have thought it would be the perfect engine for the Fiero- Light with high power over a very broad power band. Also, I have heard a 4.3 in a Fiero (But have no idea how the exhaust was set up) and it sounded just like a 2.8 V6 (Which I consider to be the best sounding V6)
Reborn756 DEC 31, 01:09 AM
Hey guys, thanks for the responses!

FieroGuru: Glad you responded, as I had seen several posts of yours regarding your 4.3L. I figured that if you showed up, you'd have some good information. And indeed you did! Now I do have a question for you: obviously the 440-T4 is going to create a lot of extra work that could possibly be avoided. Do you know of any other transverse transmission that will hold up to my power goals, that could cut down on some of the necessary block modifications? Especially that AC delete, in my 10 years of project cars, I have NEVER had one with working AC (even my daily driver, an M1028 CUCV, did not have AC from the factory). Would be nice to keep it, but I can live without it if not possible. Obviously any information you can provide is a huge help.

CVXJet: I agree with you on both accounts there: the more I look into this LV3, the better it looks. If it's really 70 pounds lighter, as you state, that's even more icing on the cake: I assumed the two to be equal weight from some previous reading I had done. Also, as I V8 guy, I can say, without shame, that whenever I step on the throttle the sound from that little 2.8 puts a smile on my face! Quiet when you want it to be, loud when you want it to be.

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- Darryl

fieroguru DEC 31, 12:08 PM
Here is one going into a toyota truck. https://ls1tech.com/forums/...yota-4x4-pickup.html
Swap Time made his harness: http://www.swaptimeusa.com/...ication_service.html

The only auto that would allow you to keep from cutting the starter pad is the 6 speed auto 6T70/75. The entire transmission case stays on the transmission side of the bellhousing, so it doesn't interfere with the starter pad. Using this transmission just adds to the complexity as you will now need non-stock mounts, custom axles/intermediate shaft, and work through the controls for the transmission. This transmission shares the same 27 spline for the tripods, so none of the stock Fiero axles will work, and mixing/matching parts on the inboard side is virtually impossible (outboard CVs you can still swap the start to install Fiero outer CVs).

The F40 6 speed manual would also support your power goals, has several final drives as well as individual gear ratios to play with to better match the engine power band any your driving style and would bypass the transmission controller complexity, but then you have the flywheel bolt pattern issue as well as spacer issue.

The downside with the LT/Ecotec3 engines is they all have an external vacuum pump added to the accessory drive, which just makes packaging in a Fiero even harder..
I haven't looked much at the accessory drive on the LT/Ecotec3 but just from pictures and knowing what I know about fitment of accessories on the LS engines, getting the alternator, vacuum pump and AC compressor to fit will be a significant challenge.

The high mount alternator should clear the strut tower, but you will want the engine as low as possible for it to clear the decklid on the top side of the engine. A notch will still likely be needed.
The AC compressor has to move - period. The normal location in a Fiero for it is occupied by the vacuum pump. Raising the AC compressor and moving it further away from the block to clear the axle will almost certainly make it interfere with the front exhaust manifold flipped to the rear. There is no room for it over the front valve cover, so the only other spot is where the vacuum pump is. You might be able to go low and place both the vacuum pump and AC pump down front, but plan on a lot of trial and error and fabrication.
The vacuum pump is for the vacuum assisted brakes (and possibly emissions... haven't fully researched). You could run an electric vacuum pump or you could run an electric power steering pump and use it for a GM hydroboost brake setup (and power steering).

The intake manifold is quite tall. The plenum/runners should fit within the frame work of the decklid, but you might need a power bulge for clearance as I don't really see a plethora of aftermarket intakes being developed for this engine. However, you might be able to cut up and modify and aluminum LT one. The swap looks cooler if you can swap the intake so the throttle body will facing the driver side, but no idea what potential road blocks that could have with all the

So I think there are options, to keep AC, but just about everything with this swap will have various levels of R&D.
Reborn756 DEC 31, 12:56 PM
Thanks for the additional information Guru!

Now in theory, couldn't the vacuum and power steering pumps be removed, and a different belt system used? Power steering isn't something I'm going to be using anyway, I much prefer the manual steering in the Fiero, find it to be part of the experience.

Is the external vacuum pump completely necessary, or is it just there for extra vacuum? If it is needed, it's not like setting up an electric pump is a difficult endeavor.

Removing these two items should give the potential to change the AC pump location, correct?

The 6T70/6T75/6T80 transmissions, do you know of anyone that can make a standalone controller for these units? I haven't found much. Also, do you think such a transmission built appropriately would be able to handle the power numbers I'm trying to achieve? It definitely sounds like using one of these could minimize necessary fabrication, as well as be lighter than the 440-T4. Both of those are excellent reasons to consider.

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- Darryl

fieroguru DEC 31, 02:05 PM
There is no power steering pump on any of the LT/Ecotec3 engines - they all run electric. The vacuum pump solution is the key to keeping A/C.

The vacuum pump is to ensure adequate vacuum for brakes. Some have deleted it, but with less vacuum, brake pedal effort as well as brake assist will be reduced, possibly a significant amount. The Vettes use an electric version.

The 6T70/75 in a fiero has been done a grand total of 1 time along side a LS2, not really sure whatever happened to the car or if the transmission lived. The guy who did it worked for an aftermarket transmission controller company.
http://www.fiero.nl/forum/Forum3/HTML/000136.html

This one says that is will control the 6T75;
http://www.zerogravityperfo...r-6l80e-6l90e-6l50e/

The 6T75 weighs about 230 lbs, so it will be a little heavier than the 195 lbs of the 440-T4 and 161 lbs of the 125C that is likely in your car today. So any weight savings from the engine choice would be offset with a heavier transmission. If you are looking for minimum weight, manual transmission is where it is at.

As for the upgrade options for the 6T70/75... no idea, I am a manual transmission person.
Daryl M JUN 13, 08:30 PM
Where are you at on this project?
Inquiring minds want to know?
R00N MAR 29, 06:14 PM
Considering this swap for a track car. Thanks to all who helped.