NicktheMillwright Posted October 20, 2022 Report Share Posted October 20, 2022 Afternoon I have a z20 head and a z24 block. Knowing the issues with a z24 head with airflow ect ect. Will a z20 head work? From what I understand it will fit and needs one oil gallery hole bunged up. Same timing chain ect. If I have some machining work done to it, would it be a better alternative to the z24? Cheers Quote Link to comment
datzenmike Posted October 20, 2022 Report Share Posted October 20, 2022 Depends what the Z20 head was off of. There were two different combustion chamber sizes. If from a 720 truck, look for the W04 casting number, I think is on the front driver's side. This has the smallest combustion chamber and will raise the Z24 compression to about 9.5. If from the A10 HL510 or S110 200sx car, they are the same as the Z24. You will likely need higher octane gas but being more efficient, the mileage increase might easily cover the added cost. Run a few tanks and see. Otherwise both Z20 heads have round intake ports where the Z24s are squarish with rounded corners. They have the same bolt pattern so the Z24 intake bolts right up. Use the Z24 intake gasket. All Z24 and Z20 heads have the same valve train. The Z24 and Z20 cam sprockets are the same but the timing chains are very different in length. If just swapping the head it will fit. There is no oil gallery to block off. Why would there be? Quote Link to comment
NicktheMillwright Posted October 20, 2022 Author Report Share Posted October 20, 2022 Ok this sounds promising. I have the one off a 200sx. Should I swap pistons while I'm at it? For the timing chain the lengths different by a whole link or half link? Quote Link to comment
datzenmike Posted October 20, 2022 Report Share Posted October 20, 2022 The Z20 pistons are way too small. What's wrong with the Z24 head that you need to replace it? The Z20 and Z24 cam sprockets are identical, so the Z24 chain will fit right on. Did you take the Z24 head off yet? Did you secure the timing chain tensioner so it can't fall out when you take the cam sprocket off??? 1 Quote Link to comment
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