Top end swap on a 3100 from a 95 se

[garagesurgeon]

I was thinking of swapping out the heads, manifold, and throttle body on my 3100 to those from a 3400 or late model 3100. I had a couple questions about this and I know some of you guys have done it so maybe you can help.

The question is which year vehicle's top end parts are best and which engine, the 94-98 3400's or the 00+ 3100's.

Both have been suggested and i'm leaning toward the 3400. If I do choose the 3400 heads tho will I have to replace my rods, rockers, and cams? I need to know what all I'll have to replace to maake the heads work. I know they came with roller rockers instead of ball type. And I also know it came with a larger fuel delivery rail which will have to be swapped in.

Either way it would be combined with a WAI cone or a CAI. Down the road I want to see about a CSC. I can't find headers but a friend of mine will lend me his tig welder so I can fab up a 2.5" exhaust from the cat back. Unless I find out more about Hi-flow cats I dont wanna remove mine, but I will get a higher flow muffler.

Christ I wish someone would make an affordable header.

[Big Joe]

Originally posted by garagesurgeon

Christ I wish someone would make an affordable header.

:agree:

[Azrael]

The 3400's heads, manifolds, and throttlebodies are identicle to the ones on 2000+ 3100's. The only difference is the lettering on the upper intake plenum. They should all pretty much bolt right on to the older 3100's without any modifications other than the EGR port. And there's even an adapter for it available at www.60degreev6.com/store

If you want headers check out Milzy's website (www.milzymotorsports.com) and email him about the header project that's underway.

[garagesurgeon]

Sweet. looks like a good mod for the cost, thanks for the info.

[voyager]

if you get the 3400 heads ( or '00+ 3100 heads ), get the rockers and pushrods too. use new headbolts. get the exhaust manifolds as well, they're bigger and will match the ports. those newer heads have roller rockers, and they aren't compatable with your old rockers, plus they're better. you don't have to replace the cam.. don't know that your ECM would like it much if you did lol. you don't have to swap fuel rails, i didn't. i don't know that i would have if i had had the parts either.. something i never really thought about because i wasn't changing injectors or anything else fuel-related.

use 3100 headgaskets and 3400 everything-else gaskets.
everything-else would be:
LIM gaskets
UIM gaskets
TB gasket
valve cover gaskets
EGR gaskets ( you need a 3100 one and a 3400 one, and the adapter azrael linked to )

[garagesurgeon]

Thanks for the gasket and parts info. The swapped fuel rail was because I was planning on using the larger injectors from the 3400. I should be able to "procure" the rockers and rods in a boneyard if I'm lucky. (jacket pocket sized parts :rofl: ) I didn't know about the exhaust manifolds but my friend and I are designing a custom header setup for this application so I won't have to buy one (hopefully). The only question I really have left is whether there's any difference between SE, and GT model 3400 motors from the 96-98 cars.
I don't know the part numbers for the 3400 heads and the upper and lower intakes and all the current parts I'm finding say they're for 3x00 and don't specify origin so I've just been looking for 96+ GA V6 parts cause they should be 3400. If you have the part numbers for these older parts please let me know. I don't want to take them off a 00+ cause I'll end up payin way more to GM for the same parts I could get on EBay or in a boneyard. In total I'm thinkin I may end up spendin less than 500 on this project if I play it right which is more or less what I'm goin for. One of the nice things about GA's is that Pontiac sold so many of 'em that even though it's a decent quality vehicle, junkyards are still full of accident cars and junked fixer uppers, so parts shouldn't be hard to come by.

[Azrael]

3400's were identicle in all the vehicles they were used in with the exception of minivans, which came with slightly bigger exhaust manifolds and a slight change to the upper intake plenum for the EGR I think.

[mikem220153]

Here is something no one has mentioned. You will need to take the Center shaft from the 3100's throttle body and install it in the 3400's throttle body WITH the 3400's throttle plate. Otherwise you won't be able to connect your throttle cable and cruise control cable from the car. Also the heater pipe fitting at the thermostat housing on the lower manifold will have to be threaded to accept the quick disconnect fitting for the heater pipe. The one on a 3400 equipped car is press fit affair while the one on the pre 2000 3100 LIM uses a quick disconnect.

[garagesurgeon]

It's little stuff like that that I was afraid would keep the car laid up while I looked for a solution, thanks for letting me know. It's a daily driver and my only car so I've gotta keep the downtime low if I can help it.

[voyager]

swapping the linkage on the TB is no big deal, it's just a couple of bolts and voila. it is necc. though. the TB itself will bolt up directly to a ny 3100/3400.

i swapped heads & manifolds last week - to work around the heater core line coming out of the thermostat, i sawed off the pipe from the 3100, sawed off the press-in fitting from the 3400, and shunted them together with a bit of hose and some clamps.

i had an issue with the metal coolant return line from the thermostat to reservoir too - my 3400 LIM just had a cap, not a fitting for a hose, and i had to take the fitting out of my old 3100 LIM to reinstall the pipe. i had it capped off at the reservoir for a day or three, but the engine was running too hot.

if you use the 3400 manifolds, and not the heads, you'll have to grind down the LIM for the rockers to clear. if you do use new heads, use a brand new set of headbolts.

depending on the year plenum you use, you might have a problem with the EGR - i think it's pre-2001 manifolds that have the horizontal EGR..? not sure on the year. anyway, you need one with a vertical EGR, to use the adapter from the 60*v6 store. there isn't anyone producing adapters for the other type of EGR mount.

i spent ~ $250 for all the parts, gaskets, etc, and also a torque wrench, because i didn't have one. i got a very good deal on the parts themselves, but you shouldn't have any problem pulling this off for well under $400, under $300 depending on what you have to pay for the top end. i did the whole thing in a day; you could definately do it in one day so long as you plan ahead.

[garagesurgeon]

So I'm gonna have to use the intake manifolds from a 2001+ 2400 to use the EGR adapter? I thought you could do the whole thing w/ parts from a 96-98. That probably would have been easier. The heads are the same for the two right? So is it better to pull the heads off an older engine to save money or are the new ones better? I'm thinkin I might save myself some cash by getting everything off the same motor, cause I can just strip the block and pull the TB UIM LIM exhaust, heads, valvetrain and pushrods all at the same time. I can find a complete 96-98 motor in a boneyard or at resale but a 2001+ is gonna be more difficult to find within my budget cause its a newer engine. Lastly I know you got a deal but just as a guestimate how much should the heads and intake manifolds from a 2001+ cost me If I have to buy them spiece by piece instead of off the whole motor. Thanks

[Azrael]

Parts from 96-98 3100's will be identicle to what you already have with a few minor exceptions. The 3400 wasn't introduced untill late 98-99 but the best flowing parts will only be found on 2000+ 3400/3100's. For a full list of the changes made to these engines throughout the years go here: http://60degreev6.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=17&page=1

[garagesurgeon]

That was really useful, thanks a lot.

[voyager]

as near as i can tell, it's the pre-2000 3400 upper intake you'd want; it's the later models that have a horizontal EGR mount. there are some adapters for the 2000+ style floating around out there but i haven't found a site that sells them outright..
the adapter at 60degreev6.com/store says it's for 96-99 style plenum.

i paid $150 for heads, manifolds, TB and some gaskets from a guy who was going to do the swap but decided to do something else. if you bought new parts it would probably cost around $400; if you stripped them from a salvage lot i'd expect to pay closer to $200 - it's hard to say. if you can find an engine that's been flooded or something but still has a useable top end, you'd probably get them cheaper than stripping an engine that would otherwise still run. gaskets and an adapter are going to cost around $100 or more.

[garagesurgeon]

OK thanks, that clears up my confusion about the manifold and stuff.

[rixGAphx]

Your '95 has the goofy PCM that was post-OBD-I and pre-OBD-II.

I'm pretty sure the new top-end, particularly the FI and ignition, will need the OBD-II from the donor car.
I don't know how well the two systems will interface. Maybe just fine, maybe not so well.

Somewhere along that timeline, '98-2002, the type of Camshaft Position Sensor changed.
The one in the '95 block may or may not provide the correct signal for the newer PCM.

The OBD-II controls the auto tranny, and interfaces with the ABS and Trac Control.
I don't know how this will interface with your '95's chassis.
Similar interface concerns with gages, I imagine.

I maybe full of it here, but one of my main fears with modern cars is mixing-and-matching electronics.
Gimme the old days when a carb had 2 bbls or 4, and a V-8 had single exhaust or duals. :D :D

Good luck.
-Rick

[Azrael]

Many have done complete swaps to newer 3100/3400's using the stock PCM. The only issue is that the PCM can't compensate for the higher flowing injectors. Easily fixed by using the injectors from the old engine. But you are right, only with a proper tuning can you get the most power out of a full engine/top-end swap. But there are other options than doing a complete computer swap. There's always aftermarket fuel management systems like Apexi's S-AFC2 or Greddy's E-Manage to help dial things in. Granted they can be limited and finicky.

[rixGAphx]

Originally posted by Azrael
Many have done complete swaps to newer 3100/3400's using the stock PCM. ....There's always aftermarket fuel management systems like Apexi's S-AFC2 or Greddy's E-Manage to help dial things in. Granted they can be limited and finicky.
Thanks for the info, I didn't know how well things might work.

It sounded like people much smarter than me were addressing all sorts of mechanical issues just fine, and I was way confused by the electronic side of it.

But then, I'm easily confused :D :D

-Rick

[garagesurgeon]

Originally posted by rixGAphx


Gimme the old days when a carb had 2 bbls or 4, and a V-8 had single exhaust or duals. :D :D



:agree:

First two cars I worked on were a 65 mustang restoration which was completed (forgive me GM gods for I knew not what I had done) and a 60 El Camino that's still in bodywork. The only modern vehicles I worked on were just for maintenence and repair, not performance. The only exception being some intake/exhaust work on my friend's civic. The lack of hands on experience w/ all the electronics is daunting, but I figure you've gotta start somewhere.

This was a concern I didn't address at all before and any more input would be helpful. I wanna go into this knowing for the most part what I'm doing so I dont run into any snags. It's great you brought it up. Thanks.

[garagesurgeon]

Ok so I am looking for heads now, can I use the higher flowing 2000+ heads If I'm using the 99 3400 manifolds? I think they should bolt up but I'm not sure. I know I'm gonna have to buy new exhausts cause my 95 3100 ones probably wont bolt up. I'm hopin to find heads w/ the roller valvetrain still in em if anyone knows a good place to get them for less $ than GM

[voyager]

yes, you can use the newer heads with the 3400 manifolds. the 95 exhaust manifolds will bolt up, but the port size won't match that of the new heads.

there aren't any problems with the electronics other than the injector issue.. just keep your old fuel rail and it'll work fine.

[garagesurgeon]

thanks