Swapping DOHC for 3X00

[IsaacHayes]

From what I've heard with the L body cars, it's better to separate them in car. Probably drop the trans down, then pull the engine out the top.........

[jmgtp]

I had a 3.1 L-body years ago. I remember when I changed the clutch I dropped the trans out the bottom and I think i would agree that pulling the two out the top in that car would be a pain. I was hoping in a larger W car it was doable. I find installing the trans in a FWD car from the bottom to be such a pain, especially when the input shaft is just refusing to comply with the clutch! So taking it out shouldn't be too bad but I'm not looking forward to the install if that is the way it has to be. I've replaced clutches in AWD vehicles and that was worlds easier that FWD!

I think the brake booster and clutch master might be the only things in the way though, and those two items come off without too much hassle... anyone tried this in a W? Keep in mind this is a getrag 284 - not a bulky 4t60e.

[2.8 Grand Prix]

I'm in the same boat that you are. I have a 1988 Grand Prix and I'm putting in a 3100 out of a '00 Malibu. It only has 86,000 miles so I'm good to go. I'm also using the stock 2.8L ECM, injectors, and motor mounts. That way the ECM will think it's still running a 2.8L, and I think the 3100 gets pretty good fuel economy too.

Once I get the swap done, I'll let you know all the details, just keep an eye on the pushrod general forum and you'll be kept up to date on my progress.

[robertisaar]

[off topic]

why are you keeping the 2.8 injectors? IIRC they are 15lb/hr? compared to the 21-23 lb/hr on the 3100....

i really wouldn't drive it hard with them in there, or else you'll run into serious lean issues around 3600-up RPM...

[/off topic]

[2.8 Grand Prix]

[Off topic]

Robert, aren't you the one who told me that I could use the 2.8 injectors? Maybe you weren't the one, Idk.
Anyway, I am sure I was told by someone that it would work (for a while) to use the 2.8 injectors. Once I get the 2.8 ECM tuned, it won't be a problem.

[Off topic]

[robertisaar]

you CAN, but they are small.

discussion to be continued in the actual thread...

[pocket-rocket]

IIRC, the Helms manual said to drop a 284/LQ1 out the bottom and take a 4T60E/LQ1 out the top. Although, Ben and I did pull the engine out of the 91 out the top (auto) and put it back in (284 swap) through the top as well. I did not separate them in the car, though. I did get a brand new set of Helms manuals off ebay for $20 shipped since my dog is now grown up and I don't have to worry about him getting hungry now (for manuals at least...) Maybe I should crack them open and check it out.

[gpse3400]

That mounting plate in your pic is not correct. You need to get one from a first or second generation w body with a GEN 3 60V6. And you can pull the TDC with the manual transmission out the top, you will just need to give it as much angle as you can.

[jmgtp]

Ok... I was worried about giving the engine a lot of angle pulling it out the top since that changes how you are loading up the hoist hooks. It means lateral forces on them and since they bolt into aluminum can they break?

Picked up a engine mount and bracket from a 95 3100 Lumina on eBay a few mins ago. This should solve my motor mount/bracket problem.

One thing I am having trouble finding is the correct a/c bracket... if anyone has one they can let go let me know!

[pocket-rocket]

Ok... I was worried about giving the engine a lot of angle pulling it out the top since that changes how you are loading up the hoist hooks. It means lateral forces on them and since they bolt into aluminum can they break?

I can't see the manual GM had made for these cars giving bad advice. If you were doing something the book said to do that was written by the manufacturer, who are you going to go after in court when something goes wrong when you followed directions to the T? If it makes you feel better, the engine/4t60e came out of the 91 from the top, and that's heavier than the LQ1/284.

[jmgtp]

Well, I didnt know it was in a manual!

The reason I question it is because I seem to remember someone had the timing cover side hoist mount break (well the aluminum on the timing cover I think) on a DOHC and I think it was because it either hit something or there was too much lateral force on it. Like I said in an earlier post of this thread... I overthink everything!

My short list of things left to buy...
3X00 power steering pump
3.1 W car high pressure ps hose
dogbone brackets, mounts and dogbones
pushrod iron a/c bracket
I need to get a load leveler as well for my hoist

-If anyone has any of these things for sale let me know. I'm still doing some searching of my own but I don't have the time for a junkyard run lately and they tend to really charge far too much in my area for used parts. I suppose I'll have better luck posting in the buy/sell/trade area when the time comes.

Other than that I think I have the rest of the hardware. I'm sure I'm going to be custom tailoring some vacuum lines, water plumbing and electrical as well. I have a used 284 clutch that supposedly only has about 1k on it. I'm probably going to take my chances and use it. Or I can use my existing clutch which works perfectly but has about 60k on it.

[pocket-rocket]

Well, there is an awful lot of manual to go through, so I can see why you didn't know it was in there The only reason I know was when we started the 5 speed swap Ben read it out loud to me. I think I basically said screw that, it's going back in the same way it came out. Besides, I remember helping him get his DOHC out of his old 92 GPSE out the top with the 284 still on it. Just make sure the top bolt on that mount is in to help distribute some of the forces into the head instead of the timing cover deal.

[jmgtp]

I wish I had the garage space to get going on this now. This would have been a perfect winter project! The most I can do during the winter is prep the LX9.

The only question mark I really have left (well for now) is how to make the front 3500 exhaust manifold work. It exits downward and in a W car that isn't too feasible. Headers would be amazing but that is outside of my budget. I may have to make a quick 180* out of the manifold and then back over the trans like a stock crossover would. That or do some serious reworking of the manifold to make it a side exit. If it is anything like the metal in the DOHC manifolds at least it welds easy with stainless wire. I suppose I could always use 3400 manifolds for an easy fix but what fun is that. I like the shorty style LX9 pieces.

Once I have the parts I think I could knock it out in a few days if I really wanted.
My plans are a bit more thorough in that I want to remove, sandblast and coat the subframe and front suspension. Then I want to go over the wireharness, replace anything that looks nasty and re-loom where necessary. I'm really going through it and making the drivetrain new again. I think it will take a solid month or so, working on the weekends, to get it done the way I want. Then I can give the vette some needed attention! She needs 4:11s bad.

[IsaacHayes]

Exactly on the front. Have it go down and loop back up and over...

[CNCguy]

I think there is a '95 Lumina 3100 A/C bracket laying around the shop. If so, you can have it for shipping if you want it.