720 4x4 EFI and Differentials

[SLO720]

Hello everyone, I will be adding efi eventually to my 86 720 pickup. To begin, I have a complete z22e, engine harness, and ecm that are from an 1983 200sx. I pieced this assemblage together purchasing the motor locally and the harness and ecu out of Louisiana (I also have a 1980 federal harness coming from Portugal).  The z22e set up I plan to run will be N/A and eventually end up in a 2WD truck but will be a good start for the 4x4. The harness I think I have figured out pretty well. AFAIK the 1983 harness does not have an external dropping resistor but will require me to add in a tach resistor for the ecu to function. I was wondering if there was an in depth how to on where to add the tach resistor and whether I'm right about the dropping resistor. I will get to diffs later. Will have some pictures up in a couple days hopefully.

 

Good things to note:

* When switching the pan from a front sump and pickup tube to a 4x4 pickup and sump you also want to switch the dipstick tube location to the rear or you won't be able to read you oil level "fail"

*Old connectors are fragile and its a good idea to order new injector pigtails 

*Replace old brittle hoses before they're hard to get to.

*Engine mounts on the motor need to be swapped to the z24 mounts 

*Buy your motor complete with accessories or good luck trying to find them, still need an z22e alternator bracket.

**If you aren't running any power steering you can run a lower alternator mount and non power steering alt bracket from a z24. 

[datzenmike]

The dropping resistor is only for use when there is an optional tachometer. The ECU works just fine without it.

 

There are metal engine brackets on either side of the block that bolt to the rubber isolators on the frame. These are often generically called engine mounts but here are 2 parts. The Z24 is 2cm or 3/4" taller so the Z24 mounts (brackets) may position the Z22 slightly lower, or not. I would try the Z24 brackets and rubber mounts first but christ don't mix them up side to side or between Z22 and Z24. 

 

All Z series engines have the dip stick in the left rear of the engine block. No need to move it anywhere but put the Z24 tube and dip stick in to reach the oil properly.

 

Z24 alternator mountings are all the same but the belt tension adjustment bracket is different if you have power steering.

 

 

 

29 minutes ago, datzenmike said:

 I think for a couple of months when the Z24 came out there was a 3.9 gear set in the 4x4 but quickly changed to 4.11. 720s are heavy!!  I would keep the 4.11s. Turbos only add power when the engine is revved up. No use for rock crawling or around town.

 

80 MPH in 5th with 4.11s and a 29" tall tire is only 3,100 RPMs..... that's nothing!!! It may sound like it's screaming but it's hardly working at all. Don't go to 3.545s or you engine will only be doing 2,700 RPMs and the turbo isn't spooled up yet. Usually with turbos the gears are switched the other way, like a 4.375 set, to get them spinning earlier and making power. 

[SLO720]

The front sump car z motors do have a front dipstick tube. I ran into that with my motor and the old location caused my dipstick to scrape the bottom of the shallow part of the pan. 

 

Also factory z22e motor accessory brackets shift everything down below the intake close to 2" to clear the inlet. It's been a lot of figuring put with this thing and it hasn't been mounted in the truck yet lol. In order to run ps I need factory brackets for a z22e. I was under the assumption that the dropping resistor was for low impedance injectors. Just trying to learn and figure this stuff out.

 

 

Also now that I'm no longer using pb it looks like I can post through mobile now 🙂

Edited November 3, 2019 by SLO720

[SLO720]

I used to drive my 4x4 up a mountain to school everyday and my truck tacked way higher than that but I guess I didnt think about it being in 4th (to keep from blowing out 5th). The trip was 300 miles a day 3 days a week. I went through one motor and put a in my third transmission.

 

Is there a good upgrade long tail or short? I think the hardbody c trans is short enough but uses a different yoke? What about a long tail maybe a 200sx early c trans? Truck currently has a long tail swapped in it and beebani disc brakes on a c200 rear. 

 

I have thought about the use of a cd009 with ka24de trans. Would need a very short intermediate shaft though lol.

Edited November 3, 2019 by SLO720

[datzenmike]

The 71C is much stronger but about 30" long so the driveshaft length will need mods. They have the same output spline as the 71B. The gearing is more towards mid range with the first 3 gears closer to 4th where yours is wide ratio with 1,2,3 more spread out and having a lower crawl speed.

[bottomwatcher]

Not to be dick but you are spending a lot of time, effort, and expense to end up with a weak lackluster ride. The ka swap with trans gains major power, reliability and way more parts availability. The Z series is a reliable motor but sold when the speed limit and moto was 55 stay alive. Drive 55 today and get stink eye, the finger and if In LA shot at. The 1986 shares a lot of parts with the hardbody. The pool for hardbody parts is 3 times that of 720 if not more. My 2 cents!

[datzenmike]

God damn it you're right the 200sx engine does have a different dip stick position. I've had two of the Z20E engines and never noticed this. I stand corrected! Just checked the Z20E block I have and it looks like it's in the rear. (but getting dark, might be wrong) So you never know what Nissan is/was up to.

 

 

[wayno]

I have a Z20S with 2 places for the oil dip stick on the left side, I moved it to the rear because I put an L head on it, it was in the middle like SLO720s post with the yellow circle around it.

Edited November 4, 2019 by wayno

[datzenmike]

I have a Z24 and it's on the back opposite to the L series. Next time I'm out back during the day I'll have a better look at the Z20E engine. 

[SLO720]

The reasoning for keeping a z motor is I'm not looking for 200+ hp or trying to source a harness and all for a 240sx, then using a truck block with 240sx intake and modifying an oil pan. More work than I want to do (Drift missile stuff around me is obnoxiously overpriced). My final plan is a turboed z20e with fully balanced internals and a small cam and then tuned. Will probably end up running that one off a haltech system or something similar with a one-six distributor and ls coils. Reliability and mild power can be had out of these motors without doing too much. 

 

Also what about ca18et transmissions or the ca20e I can pick those up kinda cheap but iirc they're like a weird transition c trans with the top plate being slightly different. I can pull bell housings I've tried it on one of the core sd22 transmissions I have. 

[datzenmike]

Turbo engines don't need a lot of cam, it's counter productive to have too much valve overlap. Stock cams are usually the best compromise for good power. Stock Z series engines run out of steam above 4,500 RPM so slightly stiffer valve springs might be a good idea if expecting to rev higher.

 

Stock Nissan engines are very well balanced as they are. Stock redline for a 86mm stroke engine is 7,000 so spend some money on ARP rod bolts. Even with a turbo the Z series head will hold you back as it does not breath that well.

 

The stock distributor is also more than good enough, don't get carried away. You said less than 200 hp.

 

You can run 5-7 PSI on stock pistons all day. More and you should switch to forged but again expensive and if boost is kept at 5-7 PSI you can get away without them. Five to seven PSI should not cause head gasket failures either, but invest in a good set of ARP studs.This should give about a 50% increase so 150 HP?

[SLO720]

So, taking this thread off course again but this popped up in one of the fb forums. It's a l20b/z20 block with a ka24e head. Utilizes a ka headgasket, z timing components and timing cover. He welded one of the rear oil galleys as it would have been matched to a water galley in the block. This setup would negate the flow problem and allow me to keep the z bottom end. I'm curious to how well it will work and compression numbers. Also will need a modified thermostat neck and he modified the timing cover to accept a ka distributor. I'd assume a early 4 plug distributor would work too.

[datzenmike]

 It's an L20B block. Here's the problem... the KA24E combustion chambers are larger, a LOT larger.

 

If you put a KA head on an L20B the compression would be 6.69 which is dismally low.  

 

If you put Z20E flattop pistons and rods in the L20B, the compression is 7.5, still dismally low.

 

 

Some questions need to be asked about this engine. Were the pistons replaced with domed ones to up the compression? Or was the head milled down to raise the compression? Or both?

 

 

 

Just hacksaw 2 or 3" off the end to fit it and the lower rad hose.

 

You can also grind out the casting and mount an L series mechanical fuel pump...

 

 

All you need add is the pump eccentric.

 

I made an aluminum plug and hammered in then filled with JB weld.

 

 

It was going on a Z22 block with 89mm KA pistons and I milled the block and the head 1mm each to get the compression up around 9 to 1.

[SLO720]

That's really cool and I might just go this route using a ka head and all for better flow. There's several jy's around me that show 200sx motors 4 & 8 plug heads. When I get some cash up I've already planned to purchase a z20e or two if the guy wants to give me a deal to move them.

 

Idk how he built his I haven't had a chance to ask him anything else. I wanted to build something different and figured a z20et would be good enough but I'd love better flow and more options of components by using a kae head. 

 

Also just received an 1980 (federal 4 plug head) engine harness from Portugal so pretty stoked about that too

[datzenmike]

The problem is getting the compression up into a useful range. The 2 liter engine is just too small and the KA combustion chambers just too big.

 

I looked up some information. The Z24 pistons are the same as the KA24E pistons but instead of a 15cc dish in the top it's 2cc. Putting KA24E pistons into the Z24 raises the compression to 8.7 if you put a KA24E head on it. You're basically making a KA24E the hard way but this is a 20% increase in displacement also. 

[wayno]

There is no substitute for displacement.