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L18 vs.L20b crank?


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To my knowledge you can't do that. L18 can stroke an L16, but L20 has different rods due to different block heights. Just checked the Datsun Bible, the crank won't fit in the journals. L18 is 78mm stroke, L20 is 86mm stroke. Journals are 59.942 for L20B, 54.942 for L16/18


It would be much easier to find an L20 block and start with that.

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L18 are 5 bolt flywheel and L20Bs are 6 bolt. L18 main bearings are 2.1631" in diameter and the L20Bs are 2.3599". The crankshaft throw or stroke on an L18 is 39mm while the L20B is 43mm.


L20B and L18 cranks will not swap.If rebuilding, the costs are about the same so do the larger motor.

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Be honest if you want low end grunt get the L20 and wait and do it right.I wish I did bac in the day. l20s are plentiful in the PNW. when getting a L20 you need to get the correct flywheel . ezest is get the 200mm so the 510 stuff all fits buy by then get the roadster clutch.

If you get a l20 with 225mm flywheel you need to order a 620 clutch with T/O bearing and sleeve.(must kits donr have a sleeve as its assumed you have the correct T/O sleeve already and kit come with the bearing.


If your do n L16/18 stuff could have left the L16 in there(I forgot what was bad on it now) throw another head on or what ever as the blocks are pretty tuff.

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