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1978 280z to L28ET Swap


Beastlikethat1

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Hey guys! I've been doing a lot of research and buying enough parts that I might need to pickup another job 🤔😂😤. I have a 1978 Datsun 280z 5 speed that I just finished taking the EFI L28 out of and I have an 1982 L28ET that I am installing. I still have the factory harness which is setup for fuel injection so it has all the injector connectors, AFM connector and TPS there. Will this harness work with the L28ET, if I just swap over the ECU? I do have the correct turbo ECU for the L28ET. I do have an extra harness that came with the L28ET BUT it's from a 240z (this L28ET was already swapped into a 240z) and is spliced and butt connected to hell... I'd prefer to use my stock harness if it takes a little modification that is fine. 

 

I also have the everything I need for the turbo engine; EXCEPT it didn't come with a new AFM, will the one from my L28 engine work? Thanks for any advice/ info and keep on Datsuning. c6WhFuR.jpg0X7cbLp.jpgA3wDKHG.jpgTY5lCTP.jpgmdJJ8IP.jpg

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I'm going to say I doubt it. These are two different generations of Z car. There are probably a dozen other reasons but off the top of my head the '82 uses a crank angle sensor (CAS) for a distributor... that's just got to have a much different plug in than the 280z harness. The CAS is needed to accurately set the ignition advance, and retard while under boost to prevent pinging. The ZX turbo will also have a knock sensoor that the 280z harness will have no provision for.

 

 

BTW you have to remove that torque converter pilot on the end of the Turbo engine's crank. It just pries off. The 280z flywheel won't go on with it in place. The '78 5 speed is not the strongest transmission for a turbo engine.

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Thanks Datzenmike. I did buy a new flywheel and clutch for a 280zx turbo engine so should I still remove it? I may just run with my 280z's current harness and look over the 240z's modified harness and see if it has the corresponding connectors I need. 

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The turbo engine was an automatic ? correct? If so, this...

Ny2GWlQ.jpg

has to come off the end of the crankshaft before the new flywheel will go on.

 

You will need the correct release bearing collar for the larger clutch you bought. It's a 240mm and the old 280z was a 225mm and it's collar will be different. This thing...

zIWK7Hw.jpg

 

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This might be a stupid question, but going back on the 82 280zx distributor that has the CAS; could I use my 280z's distributor in its place? I upgraded it a while back to an early 280zx distributor so it's running electronic ignition and such already, I'm not sure if the lobes on the distributors are the same or not or if the pedetals are even the same. Have you ever heard of anyone back tracking rather than upgrading lol?

EDIT- well I suppose that was a stupid question as I have to upgrade the ECU to the turbo ZX's and this will need that CAS signal I'm sure.

Edited by Beastlikethat1
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The CAS is just more accurately timed and stable. The other L series distributors have too much slop built into them and rattle around causing the timing to 'rattle' around. It isn't much but has a big impact on emissions. The earlier ZX E12 93 EI module is also different. It has two extra contacts on the outside and a complex electronics inside. This is to allow the timing to be advanced and retarded for better efficiency and emissions.

 

I imagine a regular EI E12 80 module distributor could be used but the fine tuning and ignition retard under boost conditions would be defeated.

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You must use the turbo version of the ECU! The connections on the wiring harness for the ECU are very different. Use the hacked together turbo harness that was on the L28ET engine. Even though the engine was previously installed in the 240Z, it should have been set up to run in that 240Z. That is a good starting point.

 

The turbo ECU will need to use the turbo distributor and AFM. The non-turbo 280Z AFM is not the same.

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On 10/28/2019 at 10:59 AM, Bleach said:

You must use the turbo version of the ECU! The connections on the wiring harness for the ECU are very different. Use the hacked together turbo harness that was on the L28ET engine. Even though the engine was previously installed in the 240Z, it should have been set up to run in that 240Z. That is a good starting point.

 

The turbo ECU will need to use the turbo distributor and AFM. The non-turbo 280Z AFM is not the same.

 

I did just notice (and am quite happy if this is the case)! That the ZX engine came with two harnesses. One appears to be fuse box/ relays/ ignition/ battery terminals etc. 

The other appears to be the ECU connection and anything involving the fuel injection, AFM and sensors. Can I get away with just swapping out that portion of the harness so I don't need to take everything in the dash apart? 

(First image is ECU harness, second is Dash harness). 

WXLyIPx.jpg

FtXomPQ.jpg

Edited by Beastlikethat1
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Fuel Injection harness: I can see by the ECU plug that the harness is for a non-turbo L28. It will not work on the turbo version.

 

One other option you have is to switch to a 300ZX turbo ECU and wiring. A turbo Z31 is often easier to find in a wrecking yard. 1984-89 There are many write-ups on how to use the Z31 ECU and MAS on the L28 turbo. You might be able to swap in the entire fuel injection wiring from a 300ZX since you say you are lacking a good injection wiring harness and turbo AFM.

 

Yes, you can and should just use the fuel injection harness by itself. Near the battery, make your own connection into main power. You might even want to run a couple relays that click on to send 12v power to the injection harness.

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For more context, the 280ZX turbo ECU upgraded to a new rectagle type of plug for the harness. The Z31 in both turbo and non-turbo form built on that same plug design. So, you can do a Z31 turbo ECU swap onto a 280ZX turbo fuel injection wiring harness. You can plug the ECU in, but will still need to do some splicing to get the Z31 MAS sensor connection installed in place of the 280ZX turbo AFM connection.

OR

you can possibly use the 300ZX injection harness with MAS and ECU. In that case you would still need to do some modifications when it comes to the fuel injector plugs. They will not be lined up the same for a V6 vs the inline 6 engine. Lengthen a few connections and other connections might be able to be used as-is.

 

I am personally going that route. L28 turbo engine. ECU and MAS from a Z31 turbo. Complete wiring harness from a 300ZX non-turbo. (I believe in the Z31 the wiring is the same or very similar in both NA and turbo) I haven't started putting this together though as I am still in the early phase of suspension and brake upgrades on my 280Z.

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20 minutes ago, Bleach said:

Fuel Injection harness: I can see by the ECU plug that the harness is for a non-turbo L28. It will not work on the turbo version.

 

One other option you have is to switch to a 300ZX turbo ECU and wiring. A turbo Z31 is often easier to find in a wrecking yard. 1984-89 There are many write-ups on how to use the Z31 ECU and MAS on the L28 turbo. You might be able to swap in the entire fuel injection wiring from a 300ZX since you say you are lacking a good injection wiring harness and turbo AFM.

 

Yes, you can and should just use the fuel injection harness by itself. Near the battery, make your own connection into main power. You might even want to run a couple relays that click on to send 12v power to the injection harness.

Interesting, that's a lot of good info thanks! So I did purchase a used turbo AFM so that's covered. You say the harnesses I posted aren't designed for the turbo engine/ turbo ECU? The guy who sold everything to me said the harness was for that engine but maybe he got everything mixed up (he had a lot of Datsun goodies). 

 

I also noticed that everything I needed was on that fuel injection harness EXCEPT the different style Dizzy connector that has the CAS built into it as well is actually on that other harness I pictured 😥

 

I guess I need to suck it up and just swap both harnesses out? I really didn't want to have to do any wire harness swapping as mine is all in great shape and everything electrical worked great LOL!

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The distributor that has the built-in crank angle sensor is unique to just the 1982-83 turbo 280ZX. 1981 turbo 280ZX has a very similar distributor but the CAS is externally mounted on one of the pullys up front and then runs wires to the distributor and also back to the ECU. As you can see, Nissan decided not to continue that design into the next two years of 280ZX turbo engine management. In the 280ZX turbo model, the ECU turns on the coil and controls the ignition advance. In the NA models, the coil just turns on with a relay (external of the ECU) and advance is done by vacuum / centrifugal. (traditional methods)

 

One more thing I forgot. The 280ZX turbo uses that CAS disc inside the distributor. That is a very similar design to the Z31 CAS that also goes inside the distributor. One other piece of doing a Z31 ECU swap is to take a CAS disc out of a Z31 distributor and install it into a 1982-83 turbo distributor. Those CAS are the same in Z31 for turbo or non-turbo. I also grabbed a couple of those for my swap and since my L28eT is from 1981, I also had to get the complete 1982/83 style turbo distributor with the matching oil pump drive spindle.

 

Sometimes I use chassis codes to describe a model. Just in case you were not familiar with them...

1970-78 z-car: S30

1979-83: S130

1984-89: Z31

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13 hours ago, Bleach said:

For more context, the 280ZX turbo ECU upgraded to a new rectagle type of plug for the harness. The Z31 in both turbo and non-turbo form built on that same plug design. So, you can do a Z31 turbo ECU swap onto a 280ZX turbo fuel injection wiring harness. You can plug the ECU in, but will still need to do some splicing to get the Z31 MAS sensor connection installed in place of the 280ZX turbo AFM connection.

OR

you can possibly use the 300ZX injection harness with MAS and ECU. In that case you would still need to do some modifications when it comes to the fuel injector plugs. They will not be lined up the same for a V6 vs the inline 6 engine. Lengthen a few connections and other connections might be able to be used as-is.

 

I am personally going that route. L28 turbo engine. ECU and MAS from a Z31 turbo. Complete wiring harness from a 300ZX non-turbo. (I believe in the Z31 the wiring is the same or very similar in both NA and turbo) I haven't started putting this together though as I am still in the early phase of suspension and brake upgrades on my 280Z.

I just went out and took some pics/ did some comparison and it appeared to me that the ECU connectors were the same? The supposed 1982 harness did fit the "turbo" ECU that was included with the engine so hopefully that is the right harness for the job.

 

I pictured the CAS connector on the other harness (not the fuel injection harness but the ignition/ battery harness) or at least I believe this is the connector for the distributor.

 

Also the ECU pictured in the car is a REMAN one which is why it has no labeling on it. I had 2 originals go bad on me so REMAN it was and that's lasted over 5 years thankfully.

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so far every picture of an ECU or wiring harness that you have posted is a non-turbo version. I think the guy who sold you this car said a lot of the parts were for a turbo Z but were in fact for the non-turbo version. The L28 turbo engine you have there for sure IS a turbo engine. The intake manifold has the correct ports that are unique to the turbo version.

 

Have you considered buying a ready-built Megasquirt ECU? They are programmable with a computer and work on the L28 turbo. That may run you about $1000 but will save you a lot of time. That ECU will also give more horsepower over the factory turbo ECU and be much less of a headache. 

 

Here are the plugs on the 1981-83 280ZX turbo ECU

 

turboECU.jpg

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On 10/31/2019 at 12:00 PM, Bleach said:

 upgrades on my 280Z.

Wow you are totally right after I did a little research. Shouldn't have listened to the guy who sold me that engine 😥. If this was your swap what would you recommend? I'm okay with buying needed items for it, I was hoping for a pretty straight forwards swap lol! That's engine swapping for ya though.

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4 minutes ago, Bleach said:

sorry, I was editing my reply as you were replying. Reload this page and make sure you see all that I typed out.

I would be willing to go the Megasquirt route, but out of curiosity would this negate the need for me to swap out the OEM harness or would I need to install a new harness kit?

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20 hours ago, Bleach said:

My suggestion is to buy a complete Megasquirt kit with ECU and wiring. You would remove the factory wiring if it is on the engine. Then connect the Megasquirt wiring.

 

 

Well I'm thinking of buying this: https://www.godzillaraceworks.com/engine-management/bolt-in-megasquirt-2-v357-engine-management-system-w-base-tune-1970-1983

 

Does this seem like a good candidate for what I'm going for and is this the "cheapest" option as far as Megasquirt plug and play goes?

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You found the most popular one. I don't know if it is the cheapest, but it is a safe company to buy from. I hope your 1982 turbo engine is really from 1982 and still has the distributor.

 

 

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7 hours ago, Bleach said:

You found the most popular one. I don't know if it is the cheapest, but it is a safe company to buy from. I hope your 1982 turbo engine is really from 1982 and still has the distributor.

 

 

I don't have pics but it has a dizzy that has a much larger cap than the one my 1978 does. Instead of having two clips holding it on, it uses screws. Instead of using two dinky wires for the optical pickup the 1982 one has a big 4 pin connector, so I hope this is correct lol!

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All three years of the turbo distributor were a larger cap than the non-turbo. You probably have the correct one. If you don't, then all you'll need to do is find the 1982-83 distributor (turbo only) and also find the oil pump spindle that drives the distributor. That item is also unique to 1982-83 turbo.

 

I plan to go with the Z31 turbo ECU so it would also require the 1982-83 turbo distributor to be used along with the conversion. My L28ET is from 1981 so I had to keep my eye out for the appropriate parts. It took about 2 years before I had them. (cheaply) The spindle itself might be harder to find in the wild, but I heard that Nissan will still sell that part brand new for around $90. You probably don't need it though.

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12 minutes ago, Bleach said:

All three years of the turbo distributor were a larger cap than the non-turbo. You probably have the correct one. If you don't, then all you'll need to do is find the 1982-83 distributor (turbo only) and also find the oil pump spindle that drives the distributor. That item is also unique to 1982-83 turbo.

 

I plan to go with the Z31 turbo ECU so it would also require the 1982-83 turbo distributor to be used along with the conversion. My L28ET is from 1981 so I had to keep my eye out for the appropriate parts. It took about 2 years before I had them. (cheaply) The spindle itself might be harder to find in the wild, but I heard that Nissan will still sell that part brand new for around $90. You probably don't need it though.

I'm putting the engine in today and will be posting updates on one of my YouTube channels "ToastyDIY" so that anyone in the future may benefit from it lol. Once the engine is in I'm ordering that Megasquirt plug and play harness which will take 4-6 weeks to show up and then I'll have the car running hopefully!

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