Z24 Block & Z20 Head

[Sambo]

Hi All,

 

I've got a carburetted Z24 in my D21 Navara/Hardbody. It's recently starting puffing steam and using water, so the plan is to give the bottom end a freshen up (just rings & bearings) and the equivalent for the head. 

 

Part of my plan for the future of the truck is to convert to multipoint efi using factory parts from a Z20E 910 bluebird and aftermarket ECU. I wanted to use the Z20E head (which I have) with round ports and the cutouts for the injectors for this, and now it seems silly to spend money on a z24 head that I plan to replace. Aside from the intake ports not matching, are there any concerns about using this combination? 

 

While the head is at the machine shop, is there any work that should be done to match them better? The long term plan, after the EFI conversion is to add a small turbo, if that changes anything.

 

Cheers,

Sam

[datzenmike]

The head gasket is blown, that's all. No need for a rebuild unless it was needing it before this. Gaskets are about $25 US.

 

 

Keep and use your old Z24 head. Z24 on top of Z22 head. See the injector notches in the Z24 head. That took less that 3 minutes to do myself using a cheap carbide burr and an electric hand drill.

 

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[Sambo]

Thanks Mike, I appreciate the input. 

 

I understand that all I need to do to be mobile is the gasket, but it's tired anyway and I want to have a nice fresh engine when I mod it in the future.

 

I wanted to use the Z20 head to match the round ports on the inlet manifold. Do you not think that necessary, or should the inlet manifold be matched to the 24 ports?

 

 

 

While I'm here, I can't find any info on the Z20 cam profile, do you know if it would offer any benefit over the Z24 for a bit more pep in N/A form?

[datzenmike]

Oh, that's right the EFI intake. Yes, if a turbo is in the future maybe go with the Z20 head/intake so it's a perfect gasket match

 

I've got 2 each of the Z20E, Z22 and Z24 heads. Had them all apart and other than the Z24's squarish shape they are all identical combustion chamber, valve size and cams. In the US a special Mileage Option head was used. This odd ball Z20 had a 9 compression, flattop pistons, a knock sensor and ignition retard and 240mm clutch and a 3.364 differential. Everything needed to maximize mileage. Unlikely you will ever see one but it had a W04 casing head with a smaller combustion chamber, exactly what you don't want on a 2.4 liter engine.. 

[Sambo]

Oh right, that's really interesting to know. I wouldn't have expected them to all have identical heads! 

 

I'd say that you're right, I'm very unlikely to see that mileage head over in New Zealand. The majority of our cars are imported JDM models, my ute is a little unusual being an NZDM model. It's not a good thing either, literally the only option offered was powersteering. 

 

Thanks again mate!