Z20E

[Davey]

Hello, so I am currently building a 1981 200sx, motor is completely torn down and I am still waiting on parts to arrive, what I am curious on is head studs, metal head gasket, and anything else I may be missing or just not able to find.

I plan to try and make the motor anywhere from 300-350hp.

The motor is getting bore out, knife edging the crank, porting/machining head, decking the block.

 

Is the Z22 head worth getting? Seems like a lot of answers lean to yes but, would rather have a clear answer other than bigger valves, are the ports better for airflow?

 

Parts I currently have:

Header, ITBs, wiseco vg30 pistons, Scat H beam connecting rods, KA24 11lbs flywheel, L series adjustable cam gear list will continue to build

 

[iceman510]

FYI, if you go that way, I have a good Z22 head available.  If you need me to check anything on it, I could do that.

Edited August 22 by iceman510

[datzenmike]

I've had two Z20E and two Z22S heads and they are exactly the same. Same cam, valve train and combustion chamber size. All Z20/22 heads have notches for EFI even if used with a carburetor. The Z24 heads are also identical except the intake ports are slightly larger and are square with rounded corners. Z20/22 are smaller and round.

 

300hp???? is rather ambitious. Won't happen on ITBs alone. That's well over 3 bar of boost!!! more than 40 PSI.  In theory, on a one hundred HP engine 3 bar would triple the output. In theory. The reality is the Z series heads don't breath well at all, so you'll need more that that.

 

Definitely look at a crank scraper and windage tray to keep oil from the spinning crankshaft.

 

Also a KA24E/KA24DE oil pump from a Hardbody. They have a 13% longer internal rotor so the oil pressure rises sooner at lower RPMs. There's just more oil delivered. Great if you are using a turbo.

 

Oil cooler.

 

Look at having the rods bushed so they are fully floating on the pins.

 

Oil squirters to cool the piston bottoms

 

Ceramic coatings for piston tops, combustion chamber and valves. It's basically insulation keeping heat in the combustion chamber so it expands the air and pushes more on the piston. Otherwise it is absorbed and drawn away by the cooling system as waste heat.

[Stoffregen Motorsports]

On 8/21/2024 at 9:32 PM, Davey said:

Hello, so I am currently building a 1981 200sx, motor is completely torn down and I am still waiting on parts to arrive, what I am curious on is head studs, metal head gasket, and anything else I may be missing or just not able to find.

I plan to try and make the motor anywhere from 300-350hp.

The motor is getting bore out, knife edging the crank, porting/machining head, decking the block.

 

Is the Z22 head worth getting? Seems like a lot of answers lean to yes but, would rather have a clear answer other than bigger valves, are the ports better for airflow?

 

Parts I currently have:

Header, ITBs, wiseco vg30 pistons, Scat H beam connecting rods, KA24 11lbs flywheel, L series adjustable cam gear list will continue to build

 

Rebello is getting 240hp from their 2350 motors, which use an L head. That's about as much as you are ever going to get from this engine. Unless you add a turbo. The Z head will never make as much HP as the L head, so I wouldn't even bother with it.

 

I'm curious - where did you get the idea that these motors can make 300-350hp? Even in full race trim with 13:1 cr and huge cam, you will never get close to 300. The GT3 spec KA24E 12 valve motors I was building back in the late 90s were getting just over 300hp and they needed a rebuild after three races.

[Davey]

5 hours ago, Stoffregen Motorsports said:

Rebello is getting 240hp from their 2350 motors, which use an L head. That's about as much as you are ever going to get from this engine. Unless you add a turbo. The Z head will never make as much HP as the L head, so I wouldn't even bother with it.

 

I'm curious - where did you get the idea that these motors can make 300-350hp? Even in full race trim with 13:1 cr and huge cam, you will never get close to 300. The GT3 spec KA24E 12 valve motors I was building back in the late 90s were getting just over 300hp and they needed a rebuild after three races.

The idea comes from modern capabilities, running modern systems on older engines are allowing them to make more power than expected, I have a decent amount of extra parts to squeeze as much power out as possible of this motor, if I have to run a turbo to get into range then I will run a turbo. Being a cross flow head usually allows more power to be made even if machine the ports and redoing them like mopars guys do with small blocks.

[Stoffregen Motorsports]

Even with the crossflow head configuration, the heads don't work that well. The floor of the intake ports is too low. And the chamber doesn't allow much room for larger valves. and if you ever float a valve, it's game over as intake and exhaust valves crash into each other.

 

I hope you have deep pockets. Building a motor to handle that much HP will require lots of cool, expensive parts. The crank will not stand up to 300hp, so either have that one nitrided, metal-laxed and cryo'd or spend the three grand to get a billet.

 

 

[datzenmike]

That's the problem the ports intake and exhaust are close to the head surface and then a bend int the combustion chamber. The valves are quite tilted as it is a hemi head, but it's not enough. On an L series head if you look down the port you look all the way to the valve head. Below.. top is a Z24 head (upside down)Not how close the head surface is from the bottom of the intake port.

 

 

 

L head. Look how much higher the intake port is. Incoming air has very little bend to get into the combustion chamber.

 

[Spiff]

You're not gettin 300 N/A, valves can't be made big enough because they'll crash and lift/duration can't be big enough because they'll crash. You can't do anything about that because thats just the way they're built. They where never made for power, they where made for emissions....
But you can do it with a turbo, gibson racing in Australia already did 300 on a Z18ET 910 way back in the early 80's. Several people down under have done 300 with various Z engines from the 1.8 to the 2.4 througout the years. It's my goal too eventually, I got to 240 but then ran out of injectors and turbo, then I blew it up after what I suspect is some piston on valve contact, so that's kind of on hold at the moment....

[datzenmike]

The good is that the Z series have a hemi head, the most efficient combustion chamber there is. They are cross flow so the intake ports don't absorb heat from the nearby exhaust ports like an L head and having intake/exhaust on opposite sides makes it easier for an inter cooler and more room for the turbo plumbing. Last is the dual plugs which vastly speeds up the combustion process to the point that there is very little ignition advance. This was designed as part of the NAPS to reduce emissions but there is also less time before TDC for detonation to occur and efficiency is increased as there is less heat produced and absorbed before TDC freeing it to expand the air and push down on the piston down stroke.     

[Stoffregen Motorsports]

4 hours ago, datzenmike said:

The good is that the Z series have a hemi head, the most efficient combustion chamber there is. They are cross flow so the intake ports don't absorb heat from the nearby exhaust ports like an L head and having intake/exhaust on opposite sides makes it easier for an inter cooler and more room for the turbo plumbing. Last is the dual plugs which vastly speeds up the combustion process to the point that there is very little ignition advance. This was designed as part of the NAPS to reduce emissions but there is also less time before TDC for detonation to occur and efficiency is increased as there is less heat produced and absorbed before TDC freeing it to expand the air and push down on the piston down stroke.     

This is what I refer to as the dark ages of automotive engineering. Manufacturers were trying everything they could think of to get better performance and lower emissions using carburetors when all they had to do was convert to EFI. Gadgets and doo hickeys filled up the inner fender wells all connected with miles of vacuum hose, and still they could barely pass. I believe the Jeep AMC V8 was the last remaining domestic vehicle to use a carburetor. They ended production before they went to EFI.

[datzenmike]

Also early emissions did nothing to stop emissions. What they did was clean it up in the exhaust pipe with a cat.

Now the engine is controlled by the emissions computer that does not allow it to run in areas where it makes them.

[Spiff]

20 hours ago, datzenmike said:

 Last is the dual plugs which vastly speeds up the combustion process to the point that there is very little ignition advance. This was designed as part of the NAPS to reduce emissions but there is also less time before TDC for detonation to occur and efficiency is increased as there is less heat produced and absorbed before TDC freeing it to expand the air and push down on the piston down stroke.     

 

This is what interests me in the 8 plug head. We didn't get those over here so all the engines I've experimented with are 4 plug heads, and every one of them have been knock-limited. I've read some papers about dual plug research and it seems emissions of course is affected but also knock resistance, which is what I'm interested in, the only problem I have is finding people with the actual knowledge of tuning an engine like that, wether or not it's actually worth it.

Because I have on multiple occasions thought about having my head drilled and tapped on the exhaust side to switch from my current cop setup to a dual vag 4 tower ignitor setup with coil near plug if it will help me extract more power and reduce chances of knock.

[datzenmike]

The single plug L series such as the L20B has a timing of 12⁰ BTDC. Z series such as the Z24 is 5⁰. A big difference. Lighting the mixture at 12⁰ means there is a long time for the mixture to build pressure as it burns. This increase in pressure can cause unburnt mixture to self ignite or knock and the peak cylinder pressure and temperature is spread out over a longer time. Peak temperature are when oxides of nitrogen are formed. Shortening the peak temperatures reduces the NOx content in the exhaust.

 

Also the dual NGK plugs are intake side BPR6ES and exhaust side BPR5ES. The Exhaust side (bottom) run a hotter plug because the in rushing intake charge cools it more.

 

 

All our non California '80 Z20 engines used in the S110 (200sx) and the A10 (HL510) were single plug. In '81* all were dual plug for reduced emissions. All top fuel dragsters run dual plugs for the reduced timing and detonation resistance.

 

*Canadian '81 Z20s were all single plug switching to dual plugs in '82 with the Z22 engine.