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Upgrade L16to z24


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3 hours ago, Alexp521 said:

Dose the fan clutch change or the whole assembly with the fan of the 720 diesel one


You just change the fan blade assembly, but they do not all interchange either, some have small clutches while others have large clutches, you have to find one that fits your clutch size, I have big clutches on my diesels, and the Z24 I put into that 1970 Datsun 521 was a 1985, and like I said, Maybe that fan was a diesel fan, it might have been the stock fan also, I do not remember, looking at that photo I can see a lot of the clutch fan assembly.

So I just went out and looked at my diesel clutch fan and took a photo, it appears that the fan in that photo of my 1970 Datsun 521 with a Z24 engine was likely the stock Z24 fan, you can see in the photo below of my diesel engine clutch fan that you cannot see the clutch part when you can see the clutch part in my photo I posted yesterday.




Here are two different fans in the photo below, the one on the left is a diesel fan which has the mount tabs at the top in the photo so it sits back over the clutch part, while the one on the right has the mount tabs at the bottom which has the fan farther forward closer to the radiator, I posted all this info to help you if you have a fan issue as there are options, but diesel fans are hard to find as there are not that many diesels left, it is likely that fan in my photo of the Z24 was the fan on the right so you likely are good unless your engine is farther forward in the engine compartment than mine was.




Edited by wayno
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The left side are more often found on '70s L series engines. The right side ones on Z series engines.


4 hours ago, Alexp521 said:

Dose the fan clutch change or the whole assembly with the fan of the 720 diesel one


The clutch is pressed onto the water pump so you have to replace both if changing one.


The 'clutch' is a silicon oil and when turned by the engine can only move a certain amount of air and can't turn any faster. This maxes out at about 1,500 fan RPMs. There is a thermostat inside that will sense over hot rad air and release more fluid which will increase the friction and allow the fan to speed up to 2,400 RPMs. Mechanical fans are on all the time drawing power. They are not needed during warm up and the vehicle speed will usually push enough air through the rad to keep the engine cool enough even at 30 MPH maybe less. The exception would be climbing a long hill or if exceptionally hot out. Naturally long idling, stop and go or stop lights may turn the electric fan on. Mine is wired to a relay triggered by a sensor in the rad return hose, through a fuse and to the battery. In the summer it's not uncommon for it to start up for 10 seconds after shut down during heat soak. A mechanical one can't do that.

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If you have a good clutch fan/water pump just cut the clutch part off in front of the press on pulley. This is what I have done .


The Z series water pumps are larger inside and move more water.


L series...




Z series. Note the taller impeller and deeper cavity...


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Take the front off and drain the oil then score across the remainder with an angle grinder and split it off leaving the bearing. This will likely be enough clearance but if you keep going do NOT get withing 1/8" of the pressed on pulley.





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It's the inner race that's shown. You can remove but stay away from that pulley. If you have clearance, definitely leave.

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I suggest a couple small spot welds to keep the pulley from loosening from the shaft.  it is only a press fit and the clutch fan is no longer there to help keep the pulley in place.

Edited by Charlie69
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So going to order 10” fans mishimoto but problem is it only provides 900 cfm will I have enough with 2 fans or wood I have to go with a different route from what I have measured it only 2.5 to 3in room for fans to go in

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I have two Subaru fans that are about 3" wider total than the rad. I rewired one backwards and placed behind the rad (pulling) on the left side and the other front right. (pushing) They still overlap.

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Ad says 521 and 520  so  they are advertising the wrong item  wher might I get a set I just need the back lenses are good no cracks but wher light socket go’s  ther shot

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1 hour ago, Alexp521 said:

So starting on new wiring tomorrow. order taillight and I’m not happy  this is what came in today 


Those are 67/68 520 tail lights.


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