My poor 95' Grand Prix

[Russell52]

Hello all I have been scanning these forms off and on,Now that I have aother grand prix,and it has taken a turn for the worse,I am looking to change a few things, while it is being rebuilt... I've read and read untill I am blue in the face,or have a headache atleast...

My engine is a 3100 sfi and from what I understand I can replace the intake,and plenum with the 3400 intake,and plenum I need verification of this,And I also understand that this gives a noticeable power increase.. I am also willing to replace the heads with the 3400 ones if I need to,but if not necessary I may not,and I hope it is a option..

I am also curios if I do swap the intake and plenum,will I need to reprogram the computer,or will the ecm be able to compensate for the added air flow,and lastly will I have to change injectors/fuel rail and fuel pump??

Thanks
sorry for the long post,These forums have gotten me all in a uproar about modding this little v6 now :P But thats a good thing..


I once hoped up a carburated 2.8 once,and that was fun little project..

[3100 MPFI]

yes you can, but you have the stamped steel rockers, and I think they interfer with the large port lower intake manifold that you will have to use. If you do a search, there is some people that have figured out how to grind off some of the material to keep the rockers from hitting. Another thing to check is if you have one of the later 1995 cars that you can swap on the roller rockers. If you swap those in, then the lower intake is not a problem.

When I did the intake swap to my 1996 Grand Prix (already had the roller rockers), the only issue I had was with one of the heater hoses. The older style was SCREWED IN, but the newer one was just PRESSED IN. I had to get the pipe from the dealer.

[Russell52]

Thanks for your reply... The search function is not functioning.. I wish it were,I am not afraid to grind a little material off the intake,if thats what its gonna take I assume that swapping the 3400 intake and plenum are worth doing? If the heads do turn out to be cracked after a die test,then I might as well get remaned 3400 heads as well..

Its looking like theres alot of info I need and not alot of time to get it,I need my car back up soon,as I have to appear in Oklahoma soon,I am a hvac tech and have no life thanks to work,long hours little pay..

Russ

[3100 MPFI]

If you have to replace the heads, get 1996 or newer. Not sure about what all would have to be done to use 3500 heads, so if you want quick repair, get like 2001~ish 3100 or 3400. They will be pretty much the same.

You can use any 1996+ 3400, or LATE 1999+ lower and upper intake manifolds, but you might need to get an EGR adapter. I can't remember what EGR the 1995 uses. 1996 got the LINEAR EGR (OBD2), but 1995 might be the DIGITAL. If you have the digital, you will want a 2000+ plenum so that you can use an EGR adatper.

[sil]

im pretty sure if you have the stamped factory roller fulcrum rockers you dont need to grind the intake
only with the after market full roller rockers

[bszopi]

95 engine had stamped stell NON-ROLLER rockers, just like the old 3.1Ls, except in 1.6 ratio. With those, the LIM has to be clearanced or the rockers will hit the runners.

BUT, there is a chance that the heads have the required notches in them for the 3x00 roller rocker pedestals. If so, then you'd just have to find a set of stock roller rockers, bolt them in and be good to go.

[IsaacHayes]

When I get some time I will put together an article on all the different intakes and what needs to be done to swap them etc.

Read this thread (both pages have images) and that will help you figure out what rockers you have.

http://www.bstuff.com/index.php?showtopic=48556&st=15

I have some pictures in the gallery of a LIM ground too.

[Russell52]

I do not have roller rockers for sure But do intend to keep the original rockers&push rods... They are all in order in a box.. So I will have to grind down the intake,Im not scared,Just need to know exactlly what to grind down,cant afford screw ups :P... What gaskets will I use with the new intake,the 3.1 or 3.4 ?? I would assume the 3.4 ones,as I am sure they have a different thickness to them..

Are the exaust manifolds larger on the 3.4 as well?? Might have to change those as well for more flow Thanks for all of your replies guys,cant wait to get my poor car back on the road...

Got the front head off today,and the walls look good,So bottom end will get left alone for now,as funds and time wont allow it to be done...

Russ

[3100 MPFI]

If you look at the pics he posted in his first thread, there are SEVERAL that show he has the stamped steel rockers. That is what I was basing a lot of what I said on.

Here is one of his pics with the stamped steel rockers:



and

[IsaacHayes]

You'll use the LIM for the heads you have. I suggest the metal felpro ones so you dont have to worry about it failing ever again.

3400 has a better rear manifold but then you'll need a new downpipe fabbed up.

Look at my pictures in the gallery and in that other link to bstuff for ideas on the LIM grind. Then you put it on and use a feeler gauge to check to see if there is enough space. Take the spark plugs out and manual turn the motor over with a socket and keep checking on all of them (4). When you are sure there is enough space, re-assemble.

[Russell52]

If you look at the pics he posted in his first thread, there are SEVERAL that show he has the stamped steel rockers. That is what I was basing a lot of what I said on.

Here is one of his pics with the stamped steel rockers:



and

For sure stamped

[IsaacHayes]

Don't have the notches in the heads do you?

[3100 MPFI]

if you use the 3400 rear exhaust manifold, you can get a downpipe from a 1999~ish LUMINA 3100. It will fit PERFECT for your car. That is what I am using in my 1988 Cutlass Supreme that I swapped a 3100 into.

Here is a pic. I can connect, and disconnect the exhaust downpipe from the top of the car instead of getting under it using the 1999 downpipe, and 3400 rear exhaust manifold. The crossover is the same.



Here you can see that the downpipe is right in the middle of the car instead of being off to one side.

[Russell52]

Don't have the notches in the heads do you?

Not sure what you mean,But here are a few photos

[bszopi]

Yes, you have the notches. Look in the 1st picture, and you will notice the grooves machined out of the heads where the rocker stud goes. It would be adventageous of you to try and find a set of roller rockers and just bolt them in. I have heard of people clearancing the LIM for the stamped rockers and grinding through the runner. Then your LIM is trashed. I'm sure someone around here has a set of rockers they'd be willing to get rid of.