z 2.2 build in 210 race car

[lonnie]

Im new here and to the Datsun world. I have and 81 210 dirt track car.

I just rebuilt a z2.2 motor for it. looking for advice on heads and cams for it to make performance?

 

[datzenmike]

Welcome to Ratsun lonnie.

 

Unfortunately the head is optimized for not much more than highway speed RPMs. Everything works well to 4K but not much thought was put into preformance improvements above this. The head basically breathes good to 4K and then breathing is restrictive and power drops off. You can't run much valve lift because the oposing valves will hit each other. The valves are so close together that you can't go larger. Both ports have a sharp bend just below the seat that can't be fixed.

 

 

 

On the plus side it's a cross flow head with the hot exhaust ports well away from the intakes. There is dual plugs to shorten the burn time and reduce ignition timing. The combustion chamber is very close to the ideal hemi shape. This engine just needs a turbo, it's a perfect candidate for it.

[Stoffregen Motorsports]

I have built dozens of big L motors, but we always take the Z head off and throw it in the scrap bin. That said, I do know there are two or three variants on the NAPS Z cylinder head. I was under the impression that the early Z20 round port head was a good on to use. I wouldn't swear to it though...

[flatcat19]

A10 cross member.

 

L head on Z block.

 

More pictures.

 

All needed. Lulz.

[Stoffregen Motorsports]

A10 cross member.

 

L head on Z block.

 

More pictures.

 

All needed. Lulz.

Good point.

 

Do the rules allow for head swaps? Then definitely a L head.

 

Intake manifolds are probably not open, so I bet you're running a Holley 2bbl on a stock intake, right?

 

What type of fuel do you use? If you use race fuel, higher CR would be desired. How about cams? Are those open or restricted? If you use race fuel and cams are open, I would try to shoot for at least 10:1. You could go as high as 11:1 with cast pistons, but longevity may be an issue. If you can use forged pistons, 12:1 with a big cam and a good exhaust.

 

You will have to do some engine math to get the CR right.

[datzenmike]

I have built dozens of big L motors, but we always take the Z head off and throw it in the scrap bin. That said, I do know there are two or three variants on the NAPS Z cylinder head. I was under the impression that the early Z20 round port head was a good on to use. I wouldn't swear to it though...

 

The L head is from an engine that leans 12 degrees to the right of verticle. This leaves room on the left side for both the manifolds. The Z series is leaning almost that amount to the left and there may not be much room for the manifolds on that side. You can reposition the engine into the L series position with L series engine brackets but now the transmission will be twisted. You can fix this by running an L series transmission. 

 

 

Z20 and Z22 heads are the same with round intake ports with notches for EFI and a 57cc combustion chamber. The Z24 head has square intake ports with rounded corners, 57cc chambers and no EFI notches. The '80 non California Z20 and Z20E heads had single spark plugs. All California and all Z22 and Z22E heads from '81 on were dual plug design. All Z24 were dual plug design. Last... the Z20 used on the Mileage option 720 from '83-'86 used a much smaller combustion chamber, around 45cc. 

[Stoffregen Motorsports]

 ... the Z20 used on the Mileage option 720 from '83-'86 used a much smaller combustion chamber, around 45cc. 

That's probably the one to have.

[datzenmike]

I theorized the existance of a smaller combustion chamber for the Z20 about 7 years ago. The mileage option has a 9 to one compression which is impossible with a flattop piston and a 57cc chamber. I reverse engineered it to find a 45 (ish) cc would produce the compression I was looking for. Several years later I found a picture of the Mileage option combustion chambers and they are indeed snaller shaped. There is even two small quench areas on them. The 45cc is also confirmed by reading Jason Grays comments on a Z head combustion chamber size he measured. He probably thinks they are all 45cc but really they are the rare exception. I have two Z20E, two Z22 S and two Z24 headls that I cc'ed and they are all the same size at 57cc.

 

The casting number on the 45cc Z head is W48? I'll check when I get home. It will only be made in dual plug design.