Replacing 7M-GE with 2JZ-GE

[Chambers]

My suggestion for wiring is to buy a EWD book for the MK4 Supra, and one for the MK3 Supra you have. That’s how I made the adapter harness for my 1UZ swap. If your car is pre-89 then I can bet the wiring will be similar to the 1UZ wiring link in my sig below, both the Lexus SC3/400 share connectors from the MK4 Supra.


I get my books from here:

http://www.faxonautoliterature.com/

 

[Roger UK]

I would have thought cut and splice is a far easier and quicker way of sorting the electrics - surely it should only be a max of about 12 wires anyway? I am into electronics and would solder them together and insulate with heatshrink (after all, once its done that's it . . and its all out of sight anyway)

That way I can come up with a table in advance of what wires to cut and connect, eg

Supra Mk3 - goes to - Supra Mk4

red/green - goes to - blue/yellow
white/blue - goes to - pink/black

etc etc

Actually doing it should then only take an hour max

What I find strange is that NOBODY seems to have written up what wires need connecting, given how many similar swaps there has been. It seems ridiculous that everybody should have to work it out from scratch - certainly if I get this done I will be publishing an easy install list !!!

 

[Chambers]

Yes, it is easier to just cut and splice connectors onto other harnesses. I personally would just rather keep the looms in one piece with an adapter between them.

It really doesn’t take to many wires to make these engines run, and as for gauge cluster, If you use the 7M sending units like water temp and oil pressure the gauges should work just fine. Being as the 2JZ-GE is a distributor based ignition system I almost think the tach will work without to much of a hiccup.

I'm into wiring/electronics too, I will surely be looking forward for a write up from you! It is a strange thing that no one really has put definitive information for this swap, but since most want a turbo its just not popular and doesnt get the support it could use.

Good luck!

 

[Kai]

Roger - if you want to cut and splice, go ahead, ignore my recommendation. You'll find out it's more hassle than just de-pinning. Yes, a table like that would work, but add a third column as to what the wire is FOR, because there are going to be at least two wires that have the same colour code, for different things.

In the FAQ's, there was a link to the wiring for the 2JZ-GTE, but that probably doesn't help you, as when most people replace a 7M, they dont bother with the 2JZ-GE. Mechanically a GE and a GTE are similar, in terms of swaps, but the wiring is totally different.

 

[Roger UK]

I appreciate your method would be more professional Kai . . . but to be honest I'm just after simple & quick ! (and I think soldering the joined wires will be just as reliable)

If I was ever likely to put a 7M back in, it would be different . . but why would I?! Especially with a ready supply of good 2JZ-GE engines here in England, even if it blew up I'd fit another one!

But yes, a third column listing the wire's purpose would be sensible.

For all that a lot of people want turbochargers, many in the USA seem to fit the 2JZ-GE engine and then put a turbocharger on it . . . so I'm hoping I can get the info I need from people that have done it!

And Chambers, yes I'm planning to use the senders from the 7M for Temp and Oil Pressure . . . and as you say the ignition circuit on both N/A engines is similar, so the Rev Counter MAY work as it is.

If not, I know that the turbo Rev Counters on the 7M just have different resistors in them, so it may just mean changing them. But once again, I'm hoping I can find this out in advance from someone that's done it!!

 

[Roger UK]

I'm still finding it hard to get definitive answers to the questions I still have about this potential engine swap! I'm sure there are people who have done this, so if YOU know, please tell me!!

Just to re-cap, I'm hoping to fit a 2JZ-GE from a Mk4 Supra to replace the 7M-GE in my Mk3 Supra (and NOT looking to ever turbocharge it)

Here's the current question I'm trying to get confirmed: Am I right in thinking that as long as I fit the bellhousing from the Mk4's W58 to MY W58 gearbox it will all mate up correctly, and line up too? (been offered one for $50)

And should I use the clutch and release bearing etc from my 7M-GE or the 2JZ-GE?

 

[Kai]

Roger - other than you, there are very few people who would bother with 'upgrading' to a 2JZ-GE for a measly 30hp. Considering the expense and the work involved - 99.9% of people would go for the GTE option, which is precisely WHY you're finding a lack of information on it.

 

[Roger UK]

I do appreciate that Kai . . the reason I'm hoping to do it it is NOT for increased power, but for a more modern engine that is more efficient and is MUCH more reliable! (as I've said before, my Supra is my daily driver, and I very rarely find I have the opportunity to use all the power I have now, so seeking MORE power seems pointless to me)

However, I'm aware that there ARE several people on here who have done it (even if some of them have LATER added a turbo to their 2JZ-GE) . . . that's why I'm hoping to get the info I need

 

[Chambers]

Your MK3 W58 will bolt up to the 2JZ-GE W58 bellhousing, there are few differences between the MK4 W58 and the MK3, shifter tower being the only major one.

 

[Roger UK]

there are few differences between the MK4 W58 and the MK3, shifter tower being the only major one.

Yes I appreciate that . . that's why I'm keeping my Mk3 W58 and just using the Bellhousing from the Mk4 . . but presume it will fit otherwise? And do I need to use the clutch from the 7M-GE or the 2JZ-GE?

 

[Chambers]

Use a clutch for the 2JZ-GE, along with the throwout bearing/ slave cylinder for the 2JZ-GE as well.

 

[Roger UK]

Use a clutch for the 2JZ-GE, along with the throwout bearing/ slave cylinder for the 2JZ-GE as well

Thank you for that . . . Is the Clutch Slave Cylinder different then? (if so, shame as I recently fitted a brand new one!)