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My 90 Colt has a 4G15 8 valve motor in it. I priced everything and I'm pretty sure I want to upgrade the head while I changing the head gasket because it's almost gone. The water pump is starting to make bearing noise too. Alright, to the point. I'm porting and polishing my 12 valve head and putting on my 8 valve block. I still have my 12 valve throttle body and MAF. I don't believe that those are any different between the two engines. I don't have to use a 12 valve harness do I? Also, I can run the 8 valve ECU can't I? If not, is there anyone here who has the 4G37 swap parts? I am going to pick up the head gasket, intake manifold gasket, exhaust manifold gasket, thermostat, water pump, timing belt, and a few other things Friday. Would I need anything else that I haven't thought of? Any help is appreciated.

I know you'll run into problems w/ the location of the distributor cap..

As far as 1.8L goodies go, I know you have to find COLT VIsta?? stuff for the 8V as opposed to the typical DSM stuff for the 12V.

Regards,
-Shawn

Try Hyundai too. Pretty much everything they made during the CSM era were carbon copies of Mitsubishi. The only differences were minor and mostly cosmetic.
Hyundai Excels I believe had the 8 valve but never the 12 valve motor. Some of the later productions also had nice tubular triple "Y" exhaust manifolds. Better flow than the cast iron and much lighter.

I did some serious experimenting with the 12 valve. Dig into my old posts in this section. Like 3 or 4 years ago.

Tubular triple "Y" exhaust manifold huh? No difference from 8v to 12v motors? Maybe I might try to find one. What Hyundai's are they out of?

And as far as the distributor goes, the 12v has it on the left (passenger side) versus the 8v has it sticking out of the right (driver's side). And as far as I know, the 8v uses an older distributor design with an external coil, and the 12v motor has one built in... Which kinda sux because I was hoping to run a better coil when I got mine, then found out that it was built in, so I cant upgrade it. THEREFORE you might have to snag some wires or use an FSM to see how you can wire up the different dizzy.

Which has me thinking- there is a blocked off port on the head on the driver's side that looks like where the dizzy would go on an 8v, but its a 12v head... you think that it could be where the dizzy can go? so 12v guys can run a better ignition system by using the 8v setup... Just a thought.

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Although alot of work, I believe it could be worth it. If the 4G15 responds well to mods like everyone says it does, I think this would result in a better power band. I think its time for me to hunt down another distributor...

On a side note: The other club I belong to for S12 generation Nissan Silvia/ 200SX/ Gazelle (84-88), the 4cyl USDM motors came with a 8 plug "twin spark" system, mainly for emissions. They are 8v SOHC motors (2.0L NA about 100whp if it is in good shape, and a 1.8L Turbo about 120hp, but responds moderately to mods because the head flows for shit).

They have 2 plugs per cylinder opposing each other


If you look close you can see the spark plug holes on the bottom and top (top ones look like bumps cuz they stick in at a wicked angle.

I guess my point is that club members developed the "dual coil mod" (yea, the car has 2 external coils) because the exhaust side cuts off at 4000rpm, they spliced wires to keep it going, AND installed 2 high output coils with better plugs and wires. People said it gave a very noticeable increase in how the car felt.

Shit, I'm waaay off topic. sorry.[/hijack]