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dbtk2
06-28-2003, 12:05 AM
What is the difference between the 3100 and the 3400? The engines basically look identical. I have heard that they are the same block only the 3400 have a bigger bore and stroke. If the blocks are the same, are the heads or intake manifolds different.

The reason I am wondering this is because I am going to take on the project of putting 3100 heads, lower & upper intake manifolds, and throttle body on my '90 TGP (obviously a 3.1 not a 3100), and I am wondering if 3400 parts are going to flow better if they are the same block.

Also, if I were to change the cam in my 3.1 to a roller cam instead of a flat tappet cam what other valvetrain components would I have to change?

Thanks,

Shawn

Robby1870
06-28-2003, 05:46 PM
The 3400 heads flow better than the 3100 heads, so definitely go with the 3400 heads. The motors are basically the same as you mentioned. If you went to the roller cam, you would have to change lifters for sure, and maybe some stuff under the timing cover, not for sure on that though. If I were you, while I had all this stuff apart, I would get a valve job, and do whatever you can to the heads to make them even better. Since you would be going with a stock 3100 (or I guess 3400) cam, you arent really going to need any stuff like rockers or pushrods. I think you can pretty much just take the heads off of the 3400 with the valve still in, and then swap the cams and tighten it all down and youre pretty much done, with the mechanical stuff.

Robby

dbtk2
06-28-2003, 07:38 PM
Well, the 3100 & 3400 ported heads I am looking at are identical, so it doesn't matter which I go with. What I want to know now is are the intake manifolds any different? If so is the 3400 intake manifold bigger or smaller than the 3100. Thanks.

Redfox340
06-28-2003, 08:02 PM
It shouldn't be, the only difference would be the casted letters on it for the literage.
But for choice, go with the 3400 intake.

- Erik

Brian P
06-29-2003, 01:02 AM
The 3400 is only bored not stroked. mkay, well you have a couple issues:

the roller lifters need more oil pressure than the flat tappet, so you cant simply throw them onto a 3.1 block without starving them to death. The oil goes to the lifters before the rockers on the 3x00. Second off, your rear exhaust manifold will still need to be used since it's unique for the turbo, unfortunately the 3100/3400 heads have D shaped exhaust ports whereas the 2.8/3.1 have oval ports. Next you have to deal with the EGR valve, as you will need to make an adaptor plate to get the 88-95 EGR to mount correctly. This is assuming you get an upper intake off a 2000 3100 OR a 96-99 3400. The egr used on current cars mounts WAY different.
Also the 3100/3400 heads generally flow the same except the 3400's have an ever so slight larger intake valve.

TurboSedan
06-29-2003, 04:47 AM
accoridng to Mick the GEN-3 motor also has better 'quench' so the combustion chamber design (or CR) is less prone to detonation even tho the higher CR that the 3100/3400 has. alot of info was gone over this on the http://www.60v6.com and i think Brian89GP mentioned someting about this last week. good luck
josua

dbtk2
06-29-2003, 09:10 AM
the roller lifters need more oil pressure than the flat tappet, so you cant simply throw them onto a 3.1 block without starving them to death. The oil goes to the lifters before the rockers on the 3x00. Second off, your rear exhaust manifold will still need to be used since it's unique for the turbo, unfortunately the 3100/3400 heads have D shaped exhaust ports whereas the 2.8/3.1 have oval ports. Next you have to deal with the EGR valve, as you will need to make an adaptor plate to get the 88-95 EGR to mount correctly. This is assuming you get an upper intake off a 2000 3100 OR a 96-99 3400. The egr used on current cars mounts WAY different.
Also the 3100/3400 heads generally flow the same except the 3400's have an ever so slight larger intake valve.


Can I use the stock 3.1 lifters / pushrods / rockers with the 3100 heads? As I said in my other posts about this, I am kind of unfamiliar with these engines and don't know the difference. This is the first time this has come up. It may become an issue, but I can probably figure something out. (Hopefully)

I know the exhaust is shaped different. This is going to be a big job, and I am planning on porting the exhaust manifolds to fit the 3100 heads. The EGR is probably going to be removed, all it does is make things dirty, and I am in Michigan so emissions don't matter, but if I do end up leaving it on (very unlikely) I will figure something out.

How the heads flow don't really matter, because I am going to be purchasing ported heads that are made for both the 3100 & 3400, they are ported identical for both engines. I will probably still stick with all 3100 parts, like I was planning on, but the thought ran through my mind that the 3400 stuff may flow better, but even if it does it can't be much, and I don't reallly want the top of my 3.1 to say 3400 on it anyways. I would MUCH rather have it say 3100 than 3400.

Robby1870
06-29-2003, 09:56 AM
Yeah, I had forgot about the roller lifters needing more oil psi. I think your best bet is to use the 3.1L cam and lifters. Plus, they do make performance cams for the 2.8/3.1L, IIRC. And yeah, I would get rid of that stupid EGR. Remember if you do, you will need a chip that is programmed to NOT have an EGR. Im sure Jeff M. can do that, cuz you said you were going to be looking into his chip. I wish you the best with the project.

Robby

Brian P
06-29-2003, 10:21 AM
Can I use the stock 3.1 lifters / pushrods / rockers with the 3100 heads? As I said in my other posts about this, I am kind of unfamiliar with these engines and don't know the difference. This is the first time this has come up. It may become an issue, but I can probably figure something out. (Hopefully)



Yes, as a matter of fact you can use the entire gen-2 setup with those heads. Install the pushrod guides, rocker studs and rockers like you would on the original heads. HOWEVER there is a little issue to be aware of, check it out here http://www.60degreev6.com/index.php?p=pages&pid=12 also this will help for a general idea of what's involved, cause there is a little bit more than meets the eye http://www.60degreev6.com/index.php?p=sections&sid=85 I am almost completely ready to do the top end swap, even more so because friday my car blew the head gasket and compression is getting into the cooling system.