Replacing Intake Manafold gaskets

[1988GTU]

Def replace the LIMG and no you dont need a PCM reflash. And if you even wanted to reflash your 95 PCM, you're SOL since it isn't supported.

[IsaacHayes]

You will need to do some things though to make it run and mate up correctly. But your computer will run it. Use your existing 3100 fuel injectors and fuel pressure regulator and it will run with those and the stock computer just fine.

Yes replacing the LIM gaskets is a good idea and good insurance so the motor doesn't fail in the future. I suggest getting the metal felpro ones so you don't have to worry about it ever again. P/N MS98003T it comes with upper gaskets, coolant o-ring and valve cover gaskets, and egr gaskets. Everything you need basically.

Read hthrough this tread it's basically the same. Only difference is you have the older EGR which is a different kind and you'll need the 2000+ EGR adapter in the store here. (looks out of stock at the moment).

EDIT: I'm not sure if the intake gasket you just put on the 3100 will fit the 3400. You can try it. I know the upper won't fit for sure, but the lower might fit or be modified to fit??? I forget what the consensus was on this...

[techgeek27]

EDIT: I'm not sure if the intake gasket you just put on the 3100 will fit the 3400. You can try it. I know the upper won't fit for sure, but the lower might fit or be modified to fit??? I forget what the consensus was on this...

were you reading my mind.. i was going to post this LOL..


Wel the thing that sucks is if i take off the upper, which i need to do to get to the lower, then I will definantly need to replace the upper because it will be crap.. And i doubt i could buy just the upper.. soooo 80 bucks down the drain...

[techgeek27]

Here is one that i found, they Looks like plastic to me...

Dorman Intake Manifold Gasket
Part Number: 615200

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=DOR&MfrPartNumber=615200&PartType=102&PTSet=A

There does seem to be a felpro for this but i don't think they are metal? Any Help here?

[techgeek27]

I made a pdf of that link you gave me for the engine swap if you want it.

[Baldeagle242]

I made a pdf of that link you gave me for the engine swap if you want it.

I HAVE COPY RIGHTS ON THAT LINK. Just kidding.
I have not been following this thread from the start but just read through it today. I do agree that it is a good idea to raplace the LIM gasket but it does not have to be done. I did not do it on the 3400 I just put in. May come back to bite me in the A$$ but we will see.
It sounds like you are just trying to get your car back on the road as cheap as you can. The swap to the 3400 is not that difficult. You can swap all the mounts and the fuel rail with injectors in less than 2 hours.(I also changed the oil pan but you may not need to.) Other than that it is just like dropping another 3100 back in. I am glad I decided to go with a 3400 and not another 3100. You will be able to find a newer low mileage 3400 for about the same price you will find an older 3100 for.

[techgeek27]

Ahhh the bald eagle... You have inspired me.. I keep getting that.. should i do it... i don't know should i .. feelings.. and this makes me happy happy happy to here this. Like i said. I have found a 3400 from a 2003 Impalla with like 50 something k miles on it and sounds like a good doner for $700. It is coming with wire harness and almost all the sensors.

the only thing that really got me worried was the puter and that sounds like a no deal soooo.

[Baldeagle242]

I have found a 3400 from a 2003 Impalla with like 50 something k miles on it and sounds like a good doner for $700. It is coming with wire harness and almost all the sensors.

the only thing that really got me worried was the puter and that sounds like a no deal soooo.

As long as you change the injectors and the fuel presure regulator and any sensors that may look different your computer will not be any problem. The 3400 block, heads and timing cover have all of the same bolt holes as your 3100. I was apprehensive about swapping to a 3400 myself but in the end I am glad I did. The Malibu has since become my daily driver and it runs great.

[IsaacHayes]

You can get new uppers all day long. It's a cheap paper gasket. In fact I've re-used my old 3100 small port paper upper gasket like 3-4 times hahha with no leaks. Although it's not recommended because the paper compresses thinner and can tear when removing. They are cheap anyways. Like $6 for uppers or something.

I gave you the part # for the felpro metal large port kit. That doorman kit is plastic... If you are going to replace the gasket and plan on keeping the car for more than 2 years I wouldn't mess with anything other than the metal gasket.

The 3400 will give you roughly an increase of power somewhere 15-20hp more. I say those #'s because the 3100/3400 were rated different numbers depending on the vehicles they were in (some had better exhausts). So that's just a conservative guess taking the middle ground...

Yeah the computer will run it fine as long as you re-use the injectors and FPR (3400 runs higher pressure and larger injectors, which your computer isn't calibrated for). The computer will be able to adjust enough to run it. If you could tune/edit the computer I'm sure you could squeak out some more HP but it's nothing to worry about. (now if you had headers, cam, etc etc you'd really have strayed far from the computers ability, and would need a tune).

The 3400 and 3100 are very similar. Only difference you will have is the 3400 is .3l more (duh) and has better flowing larger port intakes. The heads are *slightly* better too with a tiny bit bigger intake valve, but the design is more or less the same. I'm running small port 94 3100 heads with a 97 3400 lower intake manifold and 05 3500 upper intake manifold. hehe.

The cam sensor you can use from either the 3400 or 3100. It does not matter as long as you can plug it in. Not sure if the knock sensor changed in the later years or is still the same. Everything else should be the same other than the things you gotta adapt/swap connectors like the coolant sensor. Check Baldeagles's thread for the link to the 3400swap.com pdf file (since the site is down) it shows the coolant sensor plugs and how to fix them up.

[techgeek27]

you guys freakin rule sooo much thank you.. as the eagle noted this is my daily driver and i an just trying to get a car running.. As for the extra few horsepower no I am not going to complain

From what you just wrote i will now take the time to take out the old gasket and use it, the metal one, and go buy a cheap felt one for the UIM.

[IsaacHayes]

Just make sure the metal one will fit the ports and coolant passages of the 3400 heads and intake for sure. I think it won't hold the push rods in place is the main difference, but they don't use guides anyways on the new style roller rockers, the guides in the gasket on the 3400 is more or less to help you assemble it before you tighten them down.

[techgeek27]

Is there any other way of finding out other than just putting it up to it an checking?

[IsaacHayes]

Unless someone chimes in, yeah, put it up to the heads and intake, and also compare it with the old 3400 gasket you take out....

[techgeek27]

hey guys new is here and the old is out.

The main problem is guess what... egr valve .. the 2003 is vertical not my 1995 horizontal... soo till the time being can i put a plate on my erg area and block it and run it that way till your wonderful adapter become available again?

That is really my only question right now.... let me know.. If this is true.. i might have it up and running tomorrow...


oh yeah this engine is cherry and no leaks at all... i am not going to change the LIMG...

[bszopi]

Yes, you can just block it off. You will get an SES light every now and then though.