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Z22 engine build?


Thisolddatsun

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Hello everyone just brainstorming really. I have 2 motors in need of rebuilding in my yard ones a z20 and the other is a z24 atleast from what iv been told. anyways I was thinking of boring it .30 over and oversized pistons and a cam but im curious as to what other upgrades I could do? I wouldnt mind setting up a turbo. But ideally id like more torque and the motors is going to be uses for rockcrawling mostly.

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Im not to sure on if its a z24 or not. But I could just get a z24 rebuild kit. So oversized pistons arnt needed. What would be a nice cam be? I got a header exhaust and weber on my z22 in my truck right now and love the power but it could use some more. Honestly dont know much about the internals of a motor most my family just runs stock engines. Would love to learn more and do more. Just looking to upgrade my old dead rebuildable motors I have laying around.

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Well I am a lifelong Nissan fan, but when it comes to crawlers, I build Toyotas. There are so many more parts available for Toyotas: t-case gears, t-case adapters, trans adapters, heavy flywheels, diff gears, lockers, etc.

 

I would call a cam grinder like http://www.drcamshafts.com/ and have him grind a mild "smog legal" style cam. If you don't have emissions testing where you live, then maybe go a bit bigger, but not much or you start losing your torquey idle.

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The Z series are very limites by the head design. It's good but only for low speed torque. You can't add too much can as the valves will tough each other with extra lift or duration. Besides the cam moves any powr increase higher in the rev range and degrades low speed torque. I would stay stock and just get a weber 32/36 carb for it.

 

 

ID your engine by looking between the #2 and #3 exhaust side plugs between the exhaust manifold runners, down on the block where the head meets it.  A Z24 rebuild kit will not rebuild a Z20 or Z22 so ID your engine.

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  • 3 months later...

Sorry it has been so long I have been busy looking for work and finishing highschool. I have work now and working on Saving up to Get around to this Build. I have a weber 32/36 I use on my daily driver. I went out into the backyard and did some looking and apparently I have a z20 and a z22 sitting there waiting for complete rebuilds. Im thinking about rebuilding the z22 and want to make it have more torque maybe a little horsepower mostly use it for rockcrawling but I wouldn't mind being able to haul a$$ around. Been doing lots of research on blow through turbo set ups and wouldnt mind bolting on a t25/t26 whatever was on the s12's and a exhaust manifold ported to match the z22. Debating if a different carb should be used since I really want to do a turbo and since the motor needs to be rebuilt anyways I figured why not go all out and build this badboy all the way. It could also go into a 2wd datsun truck if I stumble upon one for dirt cheap. But right now its building the motor. I just dont know really where to start.

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Anything special needed to be done to fit the ka pistons? Was just reading datzenmike's lz23 build he did and I think that might be to much for me at the moment seeing as how iv never built a motor before. Just swapped some motors z20 to z22 then back to a z20 crate engine. I understand I can use most of the z22 parts and just change the piston after its bored out? What about a cam? I would like to keep it carbed enless there's a simple efi setup I can use that isnt to hard to tune.

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take your z22 and bore it to 89 mm and use ka pistons, good compromise between a lil more rpm and tractor z24 torque.

 

if its going into a 2wd build a lz23 and let er scream

 

He want's to use this in a 720 and thus it will be limited to using a Z series head. As mentioned the Z series heads are not great performers. When building a LZ2.3 the L is for L head.

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so Im thinking about doing ka 89mm pistons a mild cam (no smog where I live so maybe bigger?) Already have a header and exhaust but thatll get redone if I do a turbo. What would be a carberator to use if I do set up a turbo? Planning on using the same connecting rods from the z22 if they arnt to messed up. And whats a good performance ka piston to do? Forged, drop forged ect if there is a difference really. Maybe I can convince the manager at the local baxter autoparts to sell me a master rebuild kit for a z22 and swap the pistons with the ka 28mm ones. Still have to talk to him. I know the master rebuild kit is 450 and then the machine work. Really just brainstorming to try and get a good price quote going. Even if it might just end up getting set up and waiting to find a 620 on craigslist to make it a lz motor instead.

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A 'master rebuild kit' probably includes new pistons and rings... which you don't need and $450 is too much for a few gaskets and some bearings.

 

You need a Z24 head gasket, oil pan gasket, valve cover gasket, timing cover gasket, water pump and oil pump gasket, might as well throw new valve seals on too. I got a Z24 gasket set with all this and more for $50.

 

New Z22 main and rod bearings, KA24E piston rings I got for $120.

 

Over bore was about $25 a cylinder but I also decked the block 1mm to raise compression. If you do this be sure to check valve clearance to piston top. Z22 with KA pistons gives a boring 8.4 compression.

 

As stated the Z series head was designed with very little room for improvement. The valves are too close together and additional lift and duration can cause them to touch. Valve springs are weak. Intake and exhaust ports are too low with sudden bend at the valves causing restriction to flow. These heads do not breath as well as the L series do.

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Do a truck KA24 swap. Has EFI, 12 valves, 150hp, 2.4L for good torque.

 

Simple swap with the main advantage being the addition of a modern EFI system.

 

The reason I always jump to the swap conclusion is pure economics. You will spend hours upon hours of tinkering and tweaking your existing setup to get marginal performance at best. Take the same amount of hours and do a motor swap.

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Iv never dealt to much with efi I know a little and that it mostly runs off sensors. And I belive that's the motor in my dads pathfinder. And the timing is a pain in the ass on the z20/z22 I might be doing it wrong but iv heard from a few people around town about them. But for rockcrawling efi would be a good start at least. How simple/hard is the efi to work with?

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It's easier to deal with than carburetion. You just have to take the time to get to know the systems. It's not magic, every part has a job.

 

If you're going to consider doing an EFI swap, bite the bullet and start looking for a crashed donor truck. You can buy one for $800. I know, I've seen them on Craigslist. With a donor vehicle, you will have 99% of the parts needed to do the engine swap.

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For a crawler....find v6/auto d21(86ish-91ish) donor rig. MORE torque, no clutch to burn up.....rock solid reliable. If u still want more power after that....go wild/woolly 4.3 gm v6(most parts 350 chev).......cheapest hp per dollar with minimal firewall mods/engine bay alterations. The 3.8 chrysler motor used in Dakotas is a formidable power plant as well(cheap)!!

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Been throwing that around swaping a 4.3 v6 vortec from a s10 but I have also been debating about finding a v6 pathfinder and doing a frame/engine swap to update my running gear and power. My biggest thing is keeping electronics to a minimal. Iv heard if you sit down with a wiring diagram and a wiring harness you can pretty much chop it down to where its just the ecu. Pretty much just the bare minimum to run. Not a big fan of automatics and would prefer to keep it manual and would also like to keep my divorced tcase. Would it be more worth the time and money to go get a v6 pathfinder (87-90?) and do a body swap with my 81 720 I have?

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I wouldn't use the vortec....find an early carb motor if possible. U can use all the old school chev HP small block parts except cam/crank/int/ex/dist. I'll bet wayno has the answer if u can swap an 81 720 to Pathfinder. I prefer manual trans as well....but if u are a crawler auto IS the way 2 go.

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I could be wrong on this idea, but he wanted an engine for rock crawling.  To me, that means very good controllable, low end torque.  Peak horsepower only is available at peak RPM.

 

The way you increase HP is to shift the RPM the engine produces peak torque higher up in the RPM range.  This sacrifices torque at the lower RPM range.  In many cases the width of the usable torque band also gets smaller.

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Sorry, but I hardly know anything about a Pathfinder frame, I do 520/521s to 720 frames.

I wouldn't use the vortec....find an early carb motor if possible. U can use all the old school chev HP small block parts except cam/crank/int/ex/dist. I'll bet wayno has the answer if u can swap an 81 720 to Pathfinder. I prefer manual trans as well....but if u are a crawler auto IS the way 2 go.

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. But ideally id like more torque and the motors is going to be uses for rockcrawling mostly.

 

 

 Been doing lots of research on blow through turbo set ups and wouldnt mind bolting on a t25/t26. I just dont know really where to start.

 

 

For rock crawing you don't need a turbo. You want strong idle and low speed torque. A turbo add top end power.

 

Will the intake from a zmotor bolt to a L head? How hard would it be to switch to a L head with coils and all that?

 

No.

 

An L head and an L series front timing cover is all you really need... however the L engine is normally leaning about 20 degrees to the pass side and this gives room on the driver's side for the manifolds. Unles you use L series mounts and an L transmission this isn't going to work well.

 

 Would it be more worth the time and money to go get a v6 pathfinder (87-90?) and do a body swap with my 81 720 I have?

 

I've been under a Pathfinder and never noticed a frame. I'll check when I get home. Has a frame One thing for sure the D21 and WD21 are wider than the 720 so the wheels will stick out.

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