L28 in 240Z

[Mountain Gote]

What do you guys think? can someone give me the run down with instalation. Fabrication? Specs. Thanks very much

[zguitar71]

No fabrication just take out the L24 block and put in the L28.

[Arne]

It's done all the time. My '71 has one in it now. Simplest is to use the carbs and such from the L24. The largest "difficulty" is in the exhaust manifold, most of the L28s have round exhaust ports and so you'll need a different manifold or header. Pretty much everything else is the same. (unless you want to use the injection, which takes a lot more work.)

[Mountain Gote]

I want to use the fuel Injection, instead of carbs.

[spdkilz02]

get the wiring and ecu from the car as well, to make the install alot easier. also you will have to run a return line to the fuel tank as well.

[Arne]

I want to use the fuel Injection, instead of carbs.

That makes it considerably more difficult to make work well. My car had the injection from an '83 280ZX on it when I bought it. I found that trying to get it all to work well with the early car's wiring and fuel plumbing was hard to do, it seemed like one cobbled-up system connecting to another cobbled-up sub-system connected to...

Unlike carbs, the factory injection system is not typically a stand-alone unit. The entire fuel system has to be matched and compatible. Certainly the best way to do it would be to use the entire system from a single car, but the hidden stuff is what bites you in the end. As an example, the entire engine/injection in my car was from an '83 280ZX. They plopped the engine in, welded the stock exhaust up to the ZX downpipe, connected some of the wires, installed the ZX fuel pump and thought it was done.

But the temperature gauge didn't work, because the ZX sender was different to send temperature data to the injection computer as well. There were left-over wires hanging here and there with nothing on the early harness to connect them to. Other places the wires on the injection harness were just snipped off. ("Were those wires important? What did they do?") They kept the factory fuel piping for both the feed and the return - the feed was a bit small and caused the pump to work harder than it should, and the return line dumps into the tank in a different place than the injection return and made horrible noises in the tank from the returned fuel spraying back into the tank under pressure. And the oxygen sensor didn't work well, apparently due to the flutuations in the voltage supplied through the early car's wiring. The injector flow rates were unstable, apparently due to the pump working so hard.

All in all, my car is SO much better with the carbs back on it again. I'm a fairly experienced mechanic, and I don't think I'd want to try to do that swap myself due to the work it would take to do it right. The 240Z SU carbs are simple in comparison, and perform just as well if they are properly tuned.

In summary, I went back to the carbs and couldn't be happier. The wiring and fuel piping in the early cars is just not quite up to the injection, in my opinion. I'm certain that there are plenty of people who will tell you they've done it, but I have seen the result in my car and would never try again. If you really want a Z with injection, I'd recommend buying a 280Z instead.

[zeiss150]

the other option is (instead of carbs or stock FI) to use a stand alone ECU for your FI system(haltech or megasquirt). The stock Z and ZX FI ECU suck. If you get a stand alone model you don't need to tie into much of the 240 wireing harnes. You just need to get an engine temp sensor, map sensor, wide band O2 sensor, I think you can get an EGT sensor too, tie into the RPM loop on the dizzy,custom fuel rail and larger injectors, new fuel lines and a better fuel pump, and a 60mm throttle body. If you put that stuff on, none of it (as far as I know)will effect the 240 harness.

now if you wanna go through all that trouble go ahead.... OR.... you could just put the SU's back on and get the same performance as the custome FI system or maybe even a little better.

If you have the round top SU's Thats the way to go. The only reason I can see to use FI is if you live in a cold climate and you dont want to have a hard time starting your car in the winter OR you are going to go turbo.

Good luck and let us know what you do!

[jmortensen]

The original Datsun fuel injection sucks (sorry guys, but it is true). It has a lot of limitations and doesn't take well to modifications like camshafts, plus you have to bring all the air into the motor through the restrictive flapper AFM. If you just want it to do what it was designed for and make mediocre power and have mediocre throttle response then I guess it's OK, although by now most systems have started to get buggy and will be requiring some maintenance.

I would agree with Arne's suggestion to use roundtop SU carburetors, or if you just have to have fuel injection I'd suggest something like megasquirt or megasquirt n spark. That way you could keep the intake manifold and set up the rest to suit your particular needs. At least you could optimize it for a bigger cam, exhaust, freer flowing intake, etc.