LG5 to 3100SFI, Advice Please

[90tgpalex]

I have a 90 tgp with the stock LG5 in it and a 282 5 speed swap. After installing a new turbo the engine seized shortly after. I just picked up a 3100 SFI, i am pretty sure it is the l82 due to the SFI on the intake?
Soo my question is can i swap the bottom end from the l82 to the LG5 or would i be better off throwing the entire l82 motor in the car? and would my tgp wiring harness and pcm work? and i already planned to switch the injectors, oil pump, oil pan, and obviously the crossover with the turbo setup. Any insight on this would be greatly appreciated as i am in need of a daily driver and have limited funds. Thanks

[robertisaar]

long story short, you would be better off sticking in the entire 3100 instead of making a hybrid using the Gen2 top and Gen3 bottom. the T25 was undersized for the 3.1, and is even worse with the 3100s.

BTW: both 3100s (L82 and LG have 3100 SFI casted onto them. the LG8 has a MUCH smoother UIM and doesn't have any lines that run parallel to the cast letters/numbers.

[pocket-rocket]

BTW: both 3100s (L82 and LG have 3100 SFI casted onto them. the LG8 has a MUCH smoother UIM and doesn't have any lines that run parallel to the cast letters/numbers.

All smoothies are also large port 3100's (same as 3400), correct?

[robertisaar]

yep, the smooth top is also an indicator of being a large port manifold.

[90tgpalex]

long story short, you would be better off sticking in the entire 3100 instead of making a hybrid using the Gen2 top and Gen3 bottom. the T25 was undersized for the 3.1, and is even worse with the 3100s.

BTW: both 3100s (L82 and LG have 3100 SFI casted onto them. the LG8 has a MUCH smoother UIM and doesn't have any lines that run parallel to the cast letters/numbers.

I actually have a ebay turbo t28/25 and the compressor is actually larger than stock with the normal .80 turbine, i cant remember the specs.

If i can remember right when i went and picked it up today it had the rough casted UIM. Its got most of the accessories besides alternator and ignition which i would just use from the 3.1. The only thing that is making me timid is my lack of knowledge of both the 3.1 and the 3100 wiring harness. I was told i can use the 3.1 ecm but the crank position sensor would not work, that i am also wondering about.

[robertisaar]

the crank sensor WILL work. i can guarantee that. as long as you connect the 3X anyways, since the 24X is ignored when going to batch fire.

good L82/LG8 photos....

L82 (93-99 3100)


LG8 (late 99-05 3100)


as you can see, it's pretty noticeable.

[90tgpalex]

the crank sensor WILL work. i can guarantee that. as long as you connect the 3X anyways, since the 24X is ignored when going to batch fire.

Ok im guessing 3x and 24x are certain connectors on the wiring harness?
do you know where i could find a layout picture of both of these wiring harnesses?

[robertisaar]

sure. i uploaded the TGP wiring harness a while ago, but if you know what the 3100 came out of, i can post that one as well.

http://60degreev6.com/forum/local_links.php?action=jump&catid=10&id=141

EDIT: and 3X and 24X are refering to the two crank sensors installed on a 3100. the TGP ECM doesn't care or even know about the 24X, so you literally ignore it.

[90tgpalex]

sure. i uploaded the TGP wiring harness a while ago, but if you know what the 3100 came out of, i can post that one as well.

http://60degreev6.com/forum/local_links.php?action=jump&catid=10&id=141

EDIT: and 3X and 24X are refering to the two crank sensors installed on a 3100. the TGP ECM doesn't care or even know about the 24X, so you literally ignore it.

Alright thanks for the info. Im gunna start tearin down the tgp within the next week or so. ill make sure to take pictures and keep you guys posted. What kind of pointers would you have on engine swaps and bolt location and labeling things?

[bszopi]

You mentioned swapping the TGP oil pan over. Don't (can't?) do that. The 3x00 pan is a cast aluminum pan with side bolts going into the main caps, basically creating a 4-bolt main setup. Bottom end strength is not something you want to give up, especially on a turbo engine. Best bet is to tap the 3x00 oil pan for the oil return (which I'm guessing is the reason you wanted to swap it over in the first place).

[90tgpalex]

You mentioned swapping the TGP oil pan over. Don't (can't?) do that. The 3x00 pan is a cast aluminum pan with side bolts going into the main caps, basically creating a 4-bolt main setup. Bottom end strength is not something you want to give up, especially on a turbo engine. Best bet is to tap the 3x00 oil pan for the oil return (which I'm guessing is the reason you wanted to swap it over in the first place).

Ahh good call that makes perfect sense. Should the oil pumps be perfectly interchangeable in the two motors? And i was thinking of pulling apart the top end and checking the valve-train on the L82 do you have any suggestions on a good head gasket that would handle low boost, and do you recommend doubling them to lower the compression or keep the stock compression?

[90tgpalex]

I was hoping someone could give me some advice on the power steering pump between these two motors and also can i pull the motor out from the top even though it is a manual tranny setup. I heard things about an input shaft that will make it impossible or difficult.

[bszopi]

Separate the engine from the tranny prior to pulling it, and it will come out the top.

As far as the power steering pump, I'm pretty sure you have to use the one from the 3x00, but you need to swap out the lines. There used to be an article discussing this, but I can't find it right now.