18Z parts availability and fitment

General & Technical discussion about other Nissan/Datsun cars
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18Z parts availability and fitment

Post by SWFL »

I'm new to Datsuns, so I'm not sure what will fit what and what's good to use.

I have a 620 pickup with a L20B and a U67 that I don't fully trust ( head gasket ) and want to go through it. I found a deal on a running 18Z cross flow engine and what I assume to be a 4 speed, that's been stored a long time. I'd like to have a spare engine I can test run or freshen up with new bearings and rings to run it in my 620 while I rebuild my L20B. I heard that the crossflow Z engine isn't liked due to compression or flow issues. I'm not so concerned about that, compared to parts availability and fitment. I'd like to know if it'll bolt up to what I assume ( low 5th gear ratio ) is my non dogleg 5 speed. If not, I'd be OK using the 18Z 4 speed, as long as my driveshaft will fit without mods. My 620 is a king cab.

At the minimum I'd need a 18Z carb rebuild kit, if the engine runs OK on the bench. If not, I'd need bearings, rings and gaskets. I assume the 18Z wasn't used in the US, but was imported as a "low mileage" engine from Japan or overseas.
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Re: 18Z parts availability and fitment

Post by datzenmike »

We got Z20, Z22 and Z24 engines but I know elsewhere there were Z18s. (I suspect they were L18 blocks with Z heads on them) There was even a Z18ET. All Z series engines are cross flow and designed for low emissions at low speeds so there is not a lot of power over 4-5K and the design can't be improved much. If all you want is something to move the truck it's fine but it's a big drop from the 2 liter L20B.

The Z18 will not work with your L series 4 or 5 speed so you'll need a Z series transmission along with it. You'll need Z18 engine brackets as there is about a 20 degree difference in angle between the L and Z series engine positions.

You don't trust the L20B's head gasket? then change it! It's about $30 at NAPA and done. Have the head checked for flatness or do it yourself with a borrowed straight edge. You are allowed a 0.004" feeler gauge to slip under the straight edge. More and the head has to be surfaced. This is faster, easier and cheaper than swapping an unknown engine in.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
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Re: 18Z parts availability and fitment

Post by James »

I would agree - the L series is really a bullet-proof engine (and should be more powerful), and will have way more support going into the future than the z-series. It also goes with your 620! Lots of technical help here to assist with anything.

You don''t "trust" it? Is it leaking? Or have you just heard that they constantly fail? While the head gasket is probably one of the few "weak" points in the L series, if you have a flat head, torqued correctly with a decent head gasket - they are pretty much trouble free (provided you don't overheat it).
Finished is better than perfect......
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