chester Posted February 7, 2017 Report Share Posted February 7, 2017 I have looked everywhere without luck. I have a z24 but thinking of putting a z20 4 plug head on it. So I am trying to figure out about the chamber size, valve size and cam size. I know if the valves are smaller on the z20 head then it wouldnt be worth the time so swap as I am trying to do a cheap build with what I have access too. I also have access to ka pistons and connecting rods for a car ka that I would think would work in a z24. Any and all help would be greatly appreciated. If had everything near me I would measure myself. Quote Link to comment
Lockleaf Posted February 7, 2017 Report Share Posted February 7, 2017 Car KA rods will not work in a Z. The journal size of the ka rods is narrower than the z rods. Why the 4 plug head? You could do the same thing by plugging half the plugs on your current head and adjusting the timing. But the only benefit is aesthetics really. Quote Link to comment
datzenmike Posted February 7, 2017 Report Share Posted February 7, 2017 KA24E rods will fit any L20B Z20 Z22 or Z24 crank. Small end may be slightly too wide to properly fit a Z24 piston. It will fit but the pin has to be able to shift side to side slightly to fit variances in the crank and bore spacing. I think someone here had to mill 0.012" off each side. KA24E from a 240sx are fully floating so the pin is not contained by C clips in a Z24 piston. Use KA24E truck rods do press into the rod and are ok. Z20 heads from an A10 should be fine but if from a 720 Z20 the combustion chamber is much smaller and will raise the compression Quote Link to comment
chester Posted February 7, 2017 Author Report Share Posted February 7, 2017 I forgot about the sloposition on television big end and yes these are from a car ka. Just trying to figure out to hump the performance a little since I am going to do a head gasket before hand and regasket everything. So if I run the sohc ka pistons and z20 head. What would the compression be datzenmike Quote Link to comment
chester Posted February 7, 2017 Author Report Share Posted February 7, 2017 I would just drop a ka24de in but I don't want to spend 800 for a clapped out motor. Still haven't found oNE cheap enough but I might go vg Quote Link to comment
datzenmike Posted February 8, 2017 Report Share Posted February 8, 2017 My Z24 and Z20S head, both upside down Z20 heads are the same as the Z24 head except the intake ports are smaller and round, the Z24 heads are square-ish with rounded corners. '80 were 4 plug outside of California and ALL were 8 plug from '81 on. If possible keep the 8 plug head there is no gain going to a 4 plug head. You can run much less ignition advance with twin plug design. If you should find a Mileage Option 720 Z20 ('83-'86) they do have a smaller combustion chamber. Z24 with either Z24 or Z20S / Z20E or Z22S / Z22E heads from 200sx 2 or 4 plug design, all the same, with KA24E pistons.... 9.52 compression Z24 with mileage option Z20 head from 720 with KA24E pistons....................................................................... 11.28 compression Quote Link to comment
chester Posted February 8, 2017 Author Report Share Posted February 8, 2017 oh ok. I was thinking the z20 had a smaller combustion chamber. but if it doesn't I will just stick with the z24 head and and just re gasket it and run it. and thank you again mike 1 Quote Link to comment
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