# Z24 cylinder head



## joniblac (Nov 28, 2011)

Hi all; first post! I have an '82 Urvan with a Z20 motor. The cylinder head has a little corrosion. I bought a used Z24 head which I told fits OK. I found the valves to be of different length ( shorter) than the Z20. I bought new valves and had them cut and lapped in. I installed the head then found that the timing chain marks would not match up; there appears to be one too many links! The Z20 has 20 links between ( and including) the bright links.
Does anyone out there know if the Z24 chain is different?...John


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## smj999smj (Jan 1, 2006)

Being in the US, we don't have the Urvan, but I do know the 1984 Nissan 720 pickup used both the Z20 & Z24 engines. Comparing the timing chains at Rockauto.com, they show the Z20 using a 102 link timing chain versus the Z24 using a 106 link timing chain. Of interest, I also looked up an '80 200SX which used the Z20 and it's chain is listed at 114 links, to further confuse the issue! I do know that the Z24 block had a taller deck height than the other NAP-Z engines to increase displacement, which would make sense that the chain would be a little longer on the Z24 vs. the Z20 "if" the heads were the same, but it seems you have the opposite issue, needing a shorter chain. But, as you also point out, the heads apparantly are not the same. I guess Nissan didn't want to keep it too simple! I know Nissan used cam gears that could be put in more than one position; any chance you have the gear in the wrong set location or by moving it to the alternate position the marks line up? Or, perhaps a machine shop could remove one of the links? Just throwing some ideas at you..


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