3400 top end swap onto 3100?

[Major_Tom]

I have a 96 Grand Prix with the 3100.

 

I have a chance to have access to a 94 3400 out of a 94 Grand Prix.

 

I've heard you can do top end swaps, but I've never actually seen any pictures, or any write ups. How is it done? Are there any How to's? I would just need the intake manifold and Throttle Body, correct?

 

I'm assuming all I would need to do is take off the distributor box thingy where all the spark plugs plug into, then unbolt the intake manifold. Disconnect all of the lines to it for vaccuum and water, and then take it off.

 

Then just do the reverse for the 3400 manifold. I'm assuming it would just bolt right on, just have better airflow and a bigger throttle body. Will my throttle cable connect right up to it? And does it have connections for all of the vacuum hoses and water hoses like the 3100 one does?

 

Thanks

[THe_DeTAiL3R]

you might find some info here..

 

http://www.60degreev6.com/index.php?p=sections&sid=34

[DiscoStudd]

Wait a minute! RED FLAG! The 3.4 Liter engine in a 1994 Grand Prix is not a 3400. It's the Twin Dual Overhead Cam engine. You can't swap the top end of a 3.4 TDOHC onto a 3100. You need to find an actual pushrod 3400 (they were introduced in 96 on the minivans.) I was going to do this swap on my wife's Lumina, but going on cost alone, I've decided to replace the 3100 with an actual 3400 when the motor shits out. There are a few people who have swapped their 3100 for a 3400, and it's basically a direct drop in.

 

Check out 3400swap.com

[Major_Tom]

hmmm, ok, so if I found a minivan or something to swap from,

 

I could do what I described? swap the intakes?

[DiscoStudd]

60* V6 lost their instruction page due to a server crash last year, but I copied and pasted the instructions:

3100 to 3400 Top End Swap

 

 

 

 

One of the most popular modifications right now is the 3400 top end swap onto a 3100. The 3400 (along with the 2000+ 3100s) have much larger runners than the 94-99 3100, thus allowing for increased airflow into the engine. Stock 3400 plenum and manifolds also benefit little from increased PnPing, although gasket matching is recommended. Also, if you plan on installing a 62mm TB with this combo, you will need to port out the plenum opening to match the 62mm TB size. With that all said, let's get to the procedure!

 

 

 

Preliminary Steps

 

 

There are a few things that need to initally be done before attempting this swap. To save time (and possibly even money), do these steps first before tearing into the engine.

 

 

First of all, I recommend 97 3400 parts from the minivans (Venture, Silhouette, etc). This way, people with a 96-99 3100 won't have to worry about any EGR issues. Also, if you are buying new from GM, they are cheaper than the 00+ units. Why? Who knows... Here are the part numbers and prices for the units:

Upper Plenum : 10234990 [$126.08]

Lower Manifold : 24508396 [$61.04]

These prices are from GMPartsDirect.com. Dealership prices will most likely be higher.

 

 

 

Once you get the parts, you will need to make a couple modifications to the lower manifold. The first thing is the heater coil pipe fitting. The 3400s use a pressure fitting, whereas the 3100s use a screw in fitting. This is easily fixed though. You will need a 1/2"NPT pipe tap. Just tap out the coolant pipe hole. Be careful when doing this. You don't need to go all the way down either. I did this on my first manifold, and ended up getting the tap stuck inside the thermostat housing. I attempted to back the tap out, only to destroy all the threads that I had just created. If you get about 3/4 of the way down, you should be fine.

 

 

 

 

 

The next step is more of an observation step, although action may need to be taken. I found out the hard way that regular stamped rockers will fit the 3400 lower manifold. This is due to the larger runner size reducing the distance between the manifold and the rocker. I have included several pictures below which illustrate what to look for. If your lower manifold DOESN'T have the grindings from the factory as seen in the pictures, you will need to add them. So goto the next step... If your manifold has the stock grinding, you can skip the next modification.

 

 

 

Here is the manifold which the rockers hit (top) and a manifold with the area ground down from the factory (bottom).

 

 

This is a view of the area in question on an old style 3100. Compare with the next picture to see the clearance differences.

 

 

And here is the area (after some modification discussed in the next area) on a 3400 manifold. You should notice that the 3400 manifold runner extends deeper into the head.

 

 

 

If your manifold doesn't have the ground down areas from the factory, you will need to grind these areas down. NOTE: This should only be required for those people not having roller rocker heads. I will mention this again during the actual installation phase, but make sure you check clearances with a feeler gage before final assembly is done. Even after I ground down the manifold the first time, I had to go back and grind somemore becuase it was still touching. With that said and done, I used a die grinder to grind down the areas shown. You will most likely have to get down ~1/16" to 1/8" in order for everything to clear. Take your time while doing this and don't try to do too much at once. I have already talked with 1 person that sent the grinder bit through the runner . There should be 4 areas to grind down. And here is what it should look like when done:

 

 

Here is a view of what mine looked like when I was done grinding.

 

Here is what the back side looks like from the factory.

 

 

And here is what the front side looks like from the factory. Notice how the front side actually requires more grinding than the back side. I noticed this with the one I modified in that I needed to take more material off the front side after checking clearances, whereas the back side cleared fine.

 

 

 

The final step in the preliminary phase is the EGR adapter plate. It is once again only for those having a 94-95 3100 initially. For more info on the EGR adapter, check out the EGR Adapter Procedure.

 

 

With all that said and done, its time for the installation, right? Well, almost... at this time, you might want to do other modifications to the manifold and plenum. This could include gasket matching the runners, porting out the plenum for a larger throttle body, or possibly even painting or powercoating the pieces. All of that is up to you. For info on doing such items, check out the how-to areas. Not all of them are actually covered, but some basic PnP info is, which can then be applied to the manifold and plenum. If you still have some questions, I would prefer you bring it up on the 60DegreeV6 forums (located at GMForums.com), but I will also try to answer any emails I recieve.

 

3100 Intake Manifold Removal

 

 

 

 

 

 

Instructions

 

Removal of the Upper plenum

 

 

Relieve fuel system pressure

 

Remove your air cleaner assembly (stock, CAI, etc..)

 

Remove the EGR assembly from the plenum. Unplug the EGR plug and set the EGR aside.

 

Disconnect the following electrical connectors:

 

 

Spark plug wires

 

Throttle Position Sensor (TPS)

 

Idle Air Control (IAC) valve

 

Injector Harness

 

MAP Sensor

 

 

Disconnect the following vacuum lines:

 

 

Vacuum modulator

 

Fuel Pressure Regulator

 

Brake vaccum pipe

 

PCV

 

 

Undo the ICM from the upper plenum. If removing lower manifold as well:

 

 

Unplug 3 electrical connectors

 

Remove remaining bolts from ICM brakcet and remove from engine. You will also remove the EVAP canister purge solenoid at this time.

 

 

Remove the MAP sensor from the upper plenum

 

Undo electrical connections to the alternator (1 plug and 1 bolted wire) and remove alternator.

 

Remove 12 (6 for 3400) bolts from the upper plenum (7mm wrench)

 

Remove the upper plenum from the engine

 

 

Removal of the Lower Manifold

 

 

Drain and recover coolant

 

Remove the serpentine belt

 

At this time, it is necessary to support the engine in some way, either with a jack and block of wood under the oil pan or an engine hoist

 

Remove upper engine mount

 

Undo power steering pump (3 bolts accessible through the pulley) and set off to the side. It is not necessary to undo any of the fluid hoses from the pump.

 

Undo coolant bypass line from water pump

 

Remove radiator hose from thermostat housing

 

Undo thermostat housing (This can just be set of to the side with the bypass line still connected)

 

Remove valve covers

 

The fuel rail can be done 2 ways:

 

Ensure injector harness is unplugged

 

Remove fuel lines from fuel rail. Fuel will leak out of the rail, so be prepared to have a rag ready to keep the fuel spread to a minimum. OR

 

Remove fuel rail from lower manifold and set of to the side. To do this, undo the 2 bolts holding the rail to the lower manifold. Then carefully pry the injectors out of the lower manifold. This can be done with a screwdriver or small pry bar gently lifting up on the rail in the vicinity of each injector. Once all are undone, set the fuel rail off to the side (limited by the fuel lines)

 

 

Remove 8 lower manifold bolts

 

Remove lower manifold from engine

 

 

If replacing the lower manifold gaskets at this time:

 

 

Loosen rocker arm nuts

 

Remove pushrods. IMPORTANT!! Keep the pushrods organized. They must go back in the same position that they were removed from.

 

Remove lower intake manifold gasket

 

Clean off all of the gasket mating surfaces (including the gap between the heads on the block). Ensure all old RTV is removed from all of the surfaces.

 

Clean off any excess dirt, oil or other materials before reinstalling new gaskets and RTV

 

 

 

 

 

*60DegreeV6.com

 

You might have to change over your heads. Check if your rocker arms have roller fulcrums. If they don't, then you have to get the heads from the minivan also.

[Dannymik]

my question about the whole procedure is if its worth the time and money? Actually I would like to know if anyone knows how many hp's you gain from this? I know how the 3400's feel and like the torque they have. Thanks

[93CutlassSupreme]

off topic, but does anyone have a write up for swapping an upper 3100 onto a 3.1?

[slick]

off topic, but does anyone have a write up for swapping an upper 3100 onto a 3.1?

 

Yes, right here: http://www.domesticcrew.com/660/

 

I have pretty much a whole 3100 top end too, check out the for sale section, or PM me.

[93CutlassSupreme]

if i did decide to buy your parts, i'd be in a few weeks, when i'm out of school, working 40 hour weeks and actually making some money instead of the shit i bring home now weekly

 

thanks for the link

 

edit the link doesn't work

[slick]

Not a problem, and glad to help.

[93CutlassSupreme]

do you have a working link?

[slick]

do you have a working link?

 

Hmm... It was working the other day. I guess you'll have to check back later.

[93CutlassSupreme]

alright, i'll try it tomarrow

 

i'll pm you about those parts once i get a chance to check out that site

[DiscoStudd]

my question about the whole procedure is if its worth the time and money? Actually I would like to know if anyone knows how many hp's you gain from this? I know how the 3400's feel and like the torque they have. Thanks

 

Honestly, I don't think it's worth it. You only gain maybe 10 hp at the crank. It would be cheaper (and easier) to swap in a complete 3400 from a 2000 or newer GA, Alero, Impala, Monte, or minivan. The 2000+ 3400's cost less than the 96-99's for some reason. Since you have a 96, be sure to get an upper intake from a 96-98 minivan 3400 so the EGR valve bolts up.