MS vs. 260z injectors...

[240jz]

Ok guys I need some help here. I am collecting parts to Megasquirt my 240z. It's and early model with dual su's and an e31 head. Right now it is NA but turbocharging in not out of the question in the future. I am looking at getting a manifold from a later model car and I have a number of questions.

If I get a manifold off a n-42 car are the injectors compatiable with MS? (low vs high impedence and mecanical vs electronic fuel injection) Are they a standard shape that can be replaced with easily sourced junk yard vehicles. Do 280z and 280zx turbo manifolds have the same fuel injection boss hole diameters? Would it be better to get a later model manifold to eaise the loation of sutiable injectors. And finally, are the spacing of the injectors the same on diffrent manifolds enabling fuel rail interchangeability. Sorry for asking so many questions but I just want to be shure, and to clear some things up before I start throwing my money away.

Matt

[Tony D]

The first issue you will run into is that the manifold off a later vehicle will not fit on your E31 head without some machine work.

Namely, the four large bolts on the top of the manifold that bolt the intake manifold to the head. Those holes will need to be drilled and tapped, as well as your intake ports machined to accept the stock injector positions.

 

Others have constructed their own manifold, that is compatible with the stock carburetted manifold bolt pattern, and put the injectors up further on the intake runner (the only reason they are there stock is for emmissions).

 

But the easiest method to make something work on an early L24, is to find hte head off of a latemodel EFI L24. You will loose some compression, but not a lot.

 

Before worrying about your injectors (they are a standard Bosch Style, almost anything will fit), read the sticky that Moby has above about resistors on the stock injectors. The stock resistor block in any of the Nissan Z's from 75 to 81 will work to drop the power for the injection circuit.

But like I said, before worrying about injectors, you have to decide how you will attack the manifold issue. Once that is taken care of, THEN start worrying about injector compatibility.

 

I am in the process of converting some SU's over to a TBI setup for the stock 260 Manifold so it won't look "updated" (stealth conversion) but that project is on hold till I get some power back into the shop for the welder and Bridgeport now...

[240jz]

I was aware that the head must me modified for the n-42 type manifold. I was planning to notch the head for clearace for the injectors, so I wasn't too concerned with the head issue. Is there an issue with this approach?

As far as the bolts go I was under the impresson that the manifolds share a common pattern in respect to how they bolt to the head, apparently I am in error. Has anyone here modified their head to accept the late model manifold and can post some dimensions drilling depths. Otherwise it may be time to make my own.

[speeder]

On my '78 daily driver I run an E31 head with an N42 EFI Manifold.

 

All styles of 280Z/ZX efi manifolds use the same injector bosses and fuel rail mounting, although the stock fuel rails have had two different styles that I know of.

To get the top four large bolt holes located, I carefully mounted the manifold by the lower studs on the head so that the ports were aligned ( with a marked-up manifold gasket) and marked the new hole locations. I then drilled and tapped the required holes in the head. At least two of these penetrated the water jacket of the head. This was pretty scary but I installed 10MM X 1.25 studs using JB Weld and this has held up for 7 years and close to 100K miles with no problems.