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73 datsun 620 l20b


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Hello!, I recently acquired a 1973 datsun 620, it came with a l18 and a 5 speed 63a#1 is the code on 5 speed. My engine needed a rebuild so I decided to swap my engine for an l20b but the flywheel is a 5 bolt and the l20b, where can I find a 6 bolt flywheel, do I need a different transmission and can I run the clutch that came with the l18 engine?

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Oh where to begin.....


OK, first, the transmission used has nothing to do with the engine nor the flywheel. clutch or pressure plate turning it. Engine and transmission are totally separate and don't care about each other what-ever. So if you have an FS5W63A dogleg on your L18, it will work perfectly with an L16 or an L20B. So NO you do not need another transmission.


No one can answer if the L18 clutch can be used on the L20B without you making a few measurements.


1/ L16/18s have a 5 bolt flywheel

L20B have a 6 bolt flywheel. There is no way around this.... L16/18 flywheels do not bolt to L20Bs. Period.


2/ L16 and L18 engines all have a 200mm flywheel clutch and pressure plates, with the exception of the '74 620 truck L18 which comes with a 5 bolt 225mm flywheel clutch and pressure plate. This is a one year only exception.


3/ L20B engines from cars have a 200mm flywheel clutch and pressure plate.

L20B engines from the 620 truck have a 225mm flywheel clutch and pressure plate.



So you need to find out what flywheel is on that L18. It could be 200mm from a car or 225mm if from a '74 truck.


In addition, you need to find out what flywheel is on that L20B. It could also be 200mm or 225mm. from a car or 225mm if from a truck


If both are 200mm or if both 225mm then YES you can swap the clutch and pressure plate assembly only. Not the flywheels.(see 1/ above)

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So the L18 was from a car so '73 610 or '74 710.



As to the L20B, best to measure the flywheel rather than go by here-say

Does the L20B have a flywheel on it??? Two ways to go here....


1/ If no flywheel, get a 200mm one for the L20B, and the L18 parts will fit it. Not much sense or savings in this if the clutch is worn.


2/ Get a 225mm flywheel for the L20B and buy a new clutch kit for it. Make sure the kit includes a new release bearing collar. That's the thing that holds the release bearing and is matched to the 225mm clutch. Your 200mm collar will not work on a 225mm clutch.




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Then you have two choices 200mm or 225mm flywheel. Whichever you find the easiest then just get a clutch kit to match. Z series flywheels from the 720 truck will fit also and so will the wheels from the 240/260/280 and 280zx, 810 and Maxima.... so that widens your search.

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