im going to be starting my 5th motor for the buzzbomb this spring and the 3900 is what im aming for. now,has anyoen done a 3900 swap yet? what's still interchangeable beetween the 3400 and the 3900? heads? intake? timing cover? basicly how close is the block to the 3400? i looked at a few pics of the motor out the vehicle and it looks like the accessory belt system just wouldnt fit into a cav....info? educated guesses? pics?
I'd check v6z24.com and do search in the performance forum, you will probably find out any answers you might be looking for.
www.60degreev6.com has some in depth research on this motor.
its a 4th gen motor, common with the la 3500. heads are not interchangable with gen 3 motors due to large combustion chamber, although they will physicaly bolt on. as for a complete swap, well, engine mount locatons on both sides of the block are different. the bellhousing is still the same, and a 3.1l flywheel will bolt up. biggest issue is controlling it. its a vvt (variable valve timing) motor have has a variable intake. the stock g6 pcm will not work in a swap, and no other gm ecm controls both those. a conversion cam is in development, this will allow locking out the vvt. as for the intake, set it for one runner length and leave it, or use an rpm window switch to change it. as for ignition, gm now uses a 56x crank sensor instead of the old 7x. there is an aftermarket external crank trigger thats a gm 7x style, so with that and 3.1l coils and module, that will light it. other issues are the throttle by wire throttle body. its a big task, not easily done
*cue Mission Impossible theme music*
Someone up in french canadaland started the swap allready. He didn't know about any of the VVT stuff, VIR, the 58x CPS or any of the other differences before he bought his engine and sold his old 3400.
After we figure out a way to eliminate the VVT and controll the VIR the swap is very possible. With a very large cam you could make some really nice HP with one.
sharkey wrote:www.60degreev6.com has some in depth research on this motor.
its a 4th gen motor, common with the la 3500. heads are not interchangable with gen 3 motors due to large combustion chamber, although they will physicaly bolt on. as for a complete swap, well, engine mount locatons on both sides of the block are different. the bellhousing is still the same, and a 3.1l flywheel will bolt up. biggest issue is controlling it. its a vvt (variable valve timing) motor have has a variable intake. the stock g6 pcm will not work in a swap, and no other gm ecm controls both those. a conversion cam is in development, this will allow locking out the vvt. as for the intake, set it for one runner length and leave it, or use an rpm window switch to change it. as for ignition, gm now uses a 56x crank sensor instead of the old 7x. there is an aftermarket external crank trigger thats a gm 7x style, so with that and 3.1l coils and module, that will light it. other issues are the throttle by wire throttle body. its a big task, not easily done
how bout just using the 3900 block and rotating assembly and bolting on my 3400 heads, timing cover, lower int manifold and so on? modify my engine mounts and chage the crank sensor. as for the v v t could the 3400 cam just be put in place of the 3900?
demonik z24buzzbomb wrote:sharkey wrote:www.60degreev6.com has some in depth research on this motor.
its a 4th gen motor, common with the la 3500. heads are not interchangable with gen 3 motors due to large combustion chamber, although they will physicaly bolt on. as for a complete swap, well, engine mount locatons on both sides of the block are different. the bellhousing is still the same, and a 3.1l flywheel will bolt up. biggest issue is controlling it. its a vvt (variable valve timing) motor have has a variable intake. the stock g6 pcm will not work in a swap, and no other gm ecm controls both those. a conversion cam is in development, this will allow locking out the vvt. as for the intake, set it for one runner length and leave it, or use an rpm window switch to change it. as for ignition, gm now uses a 56x crank sensor instead of the old 7x. there is an aftermarket external crank trigger thats a gm 7x style, so with that and 3.1l coils and module, that will light it. other issues are the throttle by wire throttle body. its a big task, not easily done
how bout just using the 3900 block and rotating assembly and bolting on my 3400 heads, timing cover, lower int manifold and so on? modify my engine mounts and chage the crank sensor. as for the v v t could the 3400 cam just be put in place of the 3900?
the 3900 has larger cam journals than the 3400 so a cam swap w/o custom bearings isn't going to work very well...
and why would you put 3400 heads on a 3900? they wouldn't flow nearly enough. Hell, even stock 3500 heads flow more than heavially ported 3400 heads.
The key is going to be able to grind the 3900's cam to a useable spec and figuring out a way to hold it stationary with a standard 3x00 timing chain setup. the intake runner stuff could probably be eliminated by using the newer VVT3500's plenum. Atleast then you could keep the 3900 heads and LIM. (only a guess) but i have a feeling that the 3900's heads flow around 300 CFM on the intake side if not a little more...
