Hi guys, can the D-Jet fuel injection from a '74 2.0 work on a '74 1.8? As I understand it, the intake runners need to be drilled for 4 stud heads and the MPS has to be professionally adjusted (or replaced with a 1.7 MPS) but assuming the entire system is available can it be done? Would anything else other than the above need to be 'tweaked'?

Add head vents.
Change out the Oil filler for the Djet one.

Rich

Interesting thread. I've heard the question if L-jet could be fit on a 2.0 but never D-jet on a 1.8. If you could put 96mm pistons on the 1.8 you'd get 1911cc and the factory D-jet was for a 197X cc so they're so close in displacement that I would question if the MPS would have to be re-calibrated. Instead of drilling out the 2.0 intake runners, just buy 1.8 intake runners as they are the same size already drilled. (and you wouldn't have 5 mounting holes either).

MPS would still need to be calibrated.
Shorter stroke...different vacuum signature and fluxuation. Simple enough to do right, dont guess.

The 1.8 runners wont line up with the 2.0 liter plenum so you need the 2.0 liter runners and get them drilled for the extra bolt holes, or drill and tap the 1.8 head (there is a place for it you can see if its clean) and use the 2.0 liter setup.

With the 2.0 liter airbox, you need to get short plug wires for the drivers side rear plug...it hits the airbox.

Rich

I'm thinking it's easier to re-calibrate the MPS then to change pistons, good idea though! I was under the impression that while the inner runner diameters are the same between the 1.8 and the 2.0, the overall length is different?

Yep, I thought it was something along those lines.

How does one go about adding head vents? Can this be done with the engine in situ?

Drop the motor.
There is a casting that you need to drill out and tap...then install head vents. Search here for pics and procedure.

It could be done with motor in the car, but you would need a short drill bit of the right diameter.

Rich

The head vents absolutely need to be done? I'm thinking if it's coming out might as well put a 2.0 back in. You know, while I'm in there anyways...

I can pull a motor in under and hour.
Pull motor, tranny and HE all together.
Drill and tap two holes, install fittings.
Put motor back in car.
All that...3-4 hours...

Replace motor...then you got tranny, clutch, unknown motor issues, oil seals, all sorts of other stuff.

A used 1.8 and a used 2.0 liter probably put damn close to the same HP out for power.

Rich

2.0 and 1.8 intake manifolds are different, so my previous statement was wrong.
Click to view attachment

You don't have to have head vents. The late 2L didn't come with them. The oil filler is different. No more PCV valve. The opening is bigger and goes straight into the airbox instead of the intake plenum. I never had any overpressure or oil leakage problems with my 76.

The 1.8 runners are the same diameter but different lengths and shapes. The 2.0 runners have a smoother turn into the cylinder head. If you are redrilling the 2.0 runners you have to grind some material away so you can bolt them down correctly. I just trimmed down the 1.8 runners and used some longer rubber tubes to mate them up to the plenum.

Nothing special, use the 1.8 intakes. My 1.8 car ran fine with 75-76 D-Jet without any special mods. Didn't vent the heads and used the stock PCV valve. Just check Paul Anders site and make sure you have the all the correct versions of CHT, MPS and CPU make up the D-jet.

I ran a 1.7L D-Jet on a 1.8L motor without any mods or problems ...

Andy