L28 EFI Conversion to SU's

[viparz]

I have a 1972 240 with a L28 from a 1983 280ZX. The guy who owned the car before me made the swap and it has given me nothing but trouble, it all ended with an engine bay fire.

This car is not to be a daily driver so efficiency is not a concern. I am no mechanical genius and even less so an electrical genius. Am I right in believing that swapping to SU's would make everything much simpler? As I am teaching myself as I go an advantage of this would be being able to use stock wiring diagrams. Has anyone had any major issues that I need to look out for. What effect will this have on the compression ratio?

A list of things I will have to change, if there is anything I should add please tel me.

1. Intake manifold

2. Carbs

3. Low Pressure Fuel Pump

4. Throttle cables, linkages, choke (I am not clear on these, any clarification would be appreciated)

What can I get rid of from the EFI (Carbon canister?, Air Flow Meter etc)

[240Zdragon72]

Nope, not really. The only issue I have had was with the carb tuning. Once I figured it out the car ran fine. I would also get a electric fuel pump (around 7 psi) and a "prefilter". One that goes right after the gas tank, before the pump. This will help keep the pump clear of any unwanted debies. I have a lot of parts for the conversion if you don't already have them. As for the emmissions stuff and the canister, you can get rid of it. All you need are the carbs, fuel delivery, and maybe the studs to connect the intakes to the head. If I have left anything out, I'm sorry. You will want to look into getting the ZTherapy "Just SU's video". I did not have it, but it would have done away with a lot of hair pulling. :tapemouth Good luck with the conversion. If you need any help, I'm readily available.

P.S. Might want to get an adjustable fuel pressure regulator, too.

[ChrisA]

Has anyone had any major issues that I need to look out for.

When I did this swap I installed everything intake and fuel related from the carbed engine to the FI engine except the mechanical fuel pump. I completely stripped the L28 down on the drivers side so I could bolt up every piece off the carbed engine a piece at a time and slowly so everything went on smoothly. It's a simple conversion for a 240Z. You'll have to decide if you want the 240Z fuel rail or if you will fab up your own. In my case it was easier to use the 240Z fuel rail as it kept all the plumbing simple. The L28 head on my motor was double drilled. For FI and for carbs. Again, it was very simple.

Good luck and have fun. The L28 makes more power and torque and it really makes driving a lightweight 240Z that much more fun.

Chris

[Fun_in_my_z]

You can say that again!

Do you have to change the head as well?

[ChrisA]

Do you have to change the head as well?

I'm not sure what you mean here Bill.

Chris

[240ZX]

You can say that again!

Do you have to change the head as well?

Negative on that Bill! The NA intake will bolt right up to the EFI head. You may notice little cut-outs on the intake ports for injector clearance, but the int/exh gasket will cover them up. Note: Be sure to use a really good gasket.

[240Zdragon72]

Buy Nissan Gaskets, Not Fail-Prone. (Fel-Pro). I have had too many of them get torn or leak with in a month. I have to pull apart my turbo engine and get the fel-pro head gasket changed to a Nismo one. Don't want to chance blowing it.

[viparz]

Thanks guys, your information has been really helpful. I now have a much clearer idea of what I have to do. I am sure I will be asking many more questions once I get underway.

[Arne]

The '71 240Z I just bought has an L28 in it, complete with injection. I too will be going back to carbs, and have two questions.

1. What manifold gasket? I've seen posts saying to just use a carb-type manifold gasket to cover the notch in the intake port. But I haven't seen any carb gaskets that have the later exhaust port shape for my P79 head. Am I not looking to the right suppliers? Is there a special gasket for this? Or am I just mistaken?
   
2. The fuel pump in my car is probably not going to be able to be regulated down to a low enough pressure for the SUs. What do you folks recommend for an affordable low-pressure electric pump?