I have searched... sorry...

[Mars]

Alright, some of you know of my Camaro, some don't.

Basically has a complete LX9, 65mm turbo, cam, yadda, yadda...

I want to know something, I plan on running this setup for a bit, but am always looking into the future.

Seems that the 3900V6, LZ9 engines are way down in price these days and would appear to be the next logical step for me...

What is different from an LZ9 to an LX9 ?

Correct me if I'm wrong here, but I'll need :

1. returnless fuel rail / system.
2. VVT disabled somehow. / gettin a cam anyways.
3. variable intake runner disabled / maybe make a new box plenum with LSX TB. (OR LZ4/LZE UIM works I read)

Questions :

-Is the crank to flexplate/flyweel the same distance / bolt pattern? I need to be able to use my current 3500 flexplate.
-Are the motor mount bosses the same on the block ?
-Do 3500 headers fit a 3900 ? same exh. flange ?
-Does a RWD timing cover / crank pulley setup bolt on as it did with the LX9 ?


I was going to pick up a motor and just find out everything myself, but if there are any MAJOR snags, I'd like to know now...

so far ^ if all these items check out, it wouldn't be THAT difficult of a swap, or am I missing something.

I actually tried searching a while, alot ofthe threads that likely have my answer are 30 pages long and the information is scattered all over the place.

Thanks !!

[Superdave]

I believe the flywheel pattern is the same, maybe Marc can confirm that.

The exhaust flange pattern is different, but there are flanges available for the gen 4 pattern.

Motor mount bosses are different

Timing cover, I don't think the old RWD one will fit it but maybe Marc can confirm that as well. I know the VVT actuator would be in the way stock.. but with it eliminated and a regular cam in place it'll come down to the coolant ports and the bolt pattern.

[CNCguy]

Personally, I would love to see you work with a 3900 but hope you can get the current setup on a dyno before moving on.

There are many differences both good and bad.
Good
Bigger valves
Larger ports
Oil squirters on every cylinder
1.7:1 powdered metal rockers
Improved oiling system
Rear of block and crank are the same
Timing cover bolt pattern the same
Standard size valve seals
LS size valve springs

Bad
Side mounting holes changed
Exhaust bolt pattern changed
Cam journals are larger than previous engines
U-flow coolant system -coolant exits front of heads creating a problem for mounting accessories and the stock return system prohibits turning the UIM around.

The bad can be overcome but does takes some work. I do believe that the engine has huge potential. Switching to the LZ4 UIM is a step in the right direction.

[Mars]

U-flow coolant system -coolant exits front of heads creating a problem for mounting accessories and the stock return system prohibits turning the UIM around.

The bad can be overcome but does takes some work. I do believe that the engine has huge potential. Switching to the LZ4 UIM is a step in the right direction.

OK, well this isn't THAT bad. I can always ditch the pwr. steering on my Camaro. Motor mounts look easy enough, by every pic I can see of the 3900 the bosses for motor mounts look identicle to a 3500. ?

Does anyone have pics of the front of a 3900 with the timing cover removed, and this whole coolant setup ?? That's what I want to see.

I've seen some occurances where the LZ4 manifold (I bought one today BTW) I've see in some pictures where it's facing towards the front of the motor and it seems OK. Not sure what's up there.

And it seems that there are spacers to allow a 3X00 cam swap ?? Whare do I get these ?

There's a motor local with 50,000 miles they want 300$. Pretty cheap..

[SappySE107]

I wouldn't take a free 3900 other than to scrap it for beer money.

[ericjon262]

I wouldn't take a free 3900 other than to scrap it for beer money.

if you don't mind, please explain?

[90BlueZ]

MS3 support VVT man, don't ditch it, put it to good use instead

[SappySE107]

VVT pushrod is almost pointless for power. If you want VVT, get a DOHC so you can change the LSA. I know that from the 3.4 DOHC and changing the timing on it The 3900 is just a big 3500 with no aftermarket support. I wouldn't want it for a DD because the MPG sucks and for performance, all you can do is boost it. Mars will love that, but for me, I would rather boost something I can throw parts at to improve it, not just add fuel, and more boost. Maybe that will change, but I would bet money it won't.

[Mars]

Yeah from what I read the VVT is pointless and if I go ahead with this it will 100% be disabled and the motor will run on a 7730 at first. Why ? Because 7730's are free and they are everywhere. MS3 built is like 700$+ by the time it gets to Canada...

I can honestly see this setup making some OK power. The 3900 makes 15% more HP, stock for stock. It will spool more turbo cause it's a bigger motor. weight is likely the same or close. The little things it needs to get it to run aren't too major.

We shall see what happens, I think I'll go buy that 300$ engine and see what happens.... Sidenote, I have a 6pt. rollcage on order for the camaro.. I don't need a 3900 to justify that cage though, the LX9 justifies it quite well.

Build thread imminent.

[Weatheralls Auto]

......
Bad
.............
->Cam journals are larger than previous engines
->U-flow coolant system -coolant exits front of heads creating a problem for mounting accessories and the stock return system prohibits turning the UIM around.
.......................

These are the two that would concern me.

Cam --> After removing all VVT guess would still need a Custom cam made? or over sized bearings?
Coolant system ---> Currently running a 3400 timing cover from a U Van, not sure if this would still be possible.


Seeing as how I do not use the side mounting holes, and can make another set of custom log manis these two items are no prob for me.

[ericjon262]

These are the two that would concern me.

Cam --> After removing all VVT guess would still need a Custom cam made? or over sized bearings?
Coolant system ---> Currently running a 3400 timing cover from a U Van, not sure if this would still be possible.


Seeing as how I do not use the side mounting holes, and can make another set of custom log manis these two items are no prob for me.

roller cam bearing are bigger than standard cam bearings...

[Superdave]

IIRC the ID is smaller, OD is the same unless you can find one that has the OD of the 3900..


Not worth it for something that's not full race, i looked into them quite a bit for my build and just settled on the good teflon coated SBC bearings.

[ericjon262]

IIRC the ID is smaller, OD is the same unless you can find one that has the OD of the 3900..


Not worth it for something that's not full race, i looked into them quite a bit for my build and just settled on the good teflon coated SBC bearings.

I know, I was joking.

[Mars]

These fit ?

Yes or no...

http://www.ebay.com/itm/Siemens-Deka-60lb-EV1-SHORT-High-Imp-Fuel-Injectors-6-/390213457860?pt=Motors_Car_Truck_Parts_Accessories&hash=item5ada88d7c4&vxp=mtr

They sure do look like them.

[Mars]

Started getting parts...



Got an intake manifold and looks like my TB fits perfect, no porting required !! Well, of course an adapter of some sort is required...



Now, onto the million other issues that I gotta deal with.