620 Radiator, Shroud, Fan, and Top Hose Part Numbers

[Cardinal Grammeter]

RADIATOR:  1 for the L16, L18 and 2 for the L20B

SHROUD:  1 for each of the engines

FAN:  330mm (13")  for L16,  330mm* or 360mm  (14.2") EDIT:  350mm (13.8")  for L18, 2 for L20B

* - ambiguity in the parts manual description, see below:

 

Interchange info:

*) L20B radiator will bolt to 74 l18 and earlier but must use L20B Top Radiator Hose (Inlet is on other side)

*) L20B shroud is too wide for L16/18 radiator but can be made to work, must be notched to clear distributor, and top ribs shaved down which press against Top Radiator Hose. 

 

QUESTION:  How to tell L16 vs L18 shrouds apart?  It appears it is the fan opening diameter which is not specified.

 

11	SHROUD-RADIATOR
	21475-B5500			7309	1
	21475-B7900		7310	7408	1
	21475-B8010		7409		1

 

1	ASSY-RADIATOR
	21400-B5500	MANUAL		7408	1
	21400-B8002	MANUAL	7409	7707	1
	21400-B9800	MANUAL	7708		1

 

And cooling fans for the L16/18:

 

15	FAN-COOLING (D=330MM)
	21060-A4600	L16,L18		7309	1
	21060-N0100	TROPICS		7309	1
	FAN-COOLING (D=350MM)
	21060-U2000		7310	7408	1

 

9	ASSY-FAN,COOLING (FOR COOLER)
	21060-B8001	OP	from 7608		1
	ASSY-FAN,COOLING
	21060-U6000	L20B			1

 

TOP RADIATOR HOSES:

 

18	HOSE-WATER
	14056-23001	L16			1

 

16	HOSE-WATER,INLET TO PIPE
	14056-23001	L18			1

 

L20B could not find.  L16 & L18 show radiator hose under Manifolds but L20B does not have the Intake Manifold under Manifolds.

Edited September 14, 2021 by Cardinal Grammeter

[datzenmike]

'75 and later 620 radiator supports are bowed outward to fit the deeper L20B radiators.

 

'75- L20B upper radiator hose 21501-U6700. Lower hose 21503-B8000

 

37 minutes ago, Cardinal Grammeter said:

 

 

 

 

QUESTION:  How to tell L16 vs L18 shrouds apart?  It appears it is the fan opening diameter which is not specified.

 

 

'73 shroud is 21475-B5500

'74 shroud is the same just a superseded B5500 to B7900 number.

 

The difference between 330mm and 350mm is only a cm around the fan and the hole opening. The opening is never going to be 330mm and 350mm and is probably 400 or more to allow engine movement so 1 cm isn't going to preclude using the one shroud.

 

 

What does this mean?

 

37 minutes ago, Cardinal Grammeter said:

 L16 & L18 show radiator hose under Manifolds but L20B does not have the Intake Manifold under Manifolds.

 

A TROPICAL fan may be same diameter but have extra blade. I've often wondered if the blade angle might be different to cut a deeper bight out of the air like a plane propeller.

[Cardinal Grammeter]

23 minutes ago, datzenmike said:

 

What does this mean?

 

For the L16 and L18, I found the upper radiator hose under ENGINE >  MANIFOLDS where both the INTAKE and EXHAUST were shown.

 

For some reason the L20B  ENGINE > MANIFOLDS only shows the exhaust.  There are no L and R arrows to click on to show another pic/view.  I could not find the Intake Manifold listing.  Not under MANIFOLDS?

[Cardinal Grammeter]

29 minutes ago, datzenmike said:

'75 and later 620 radiator supports are bowed outward to fit the deeper L20B radiators.

 

 

Interesting, I put a L20B aluminum plastic tank Advance Auto radiator in my 74 L18 w/o a fan clearance problem.  However the L20B shroud had to be notched to clear the distributor and top shaved to not rub on top radiator hose.

 

If they moved the radiator forward, my shroud interferences might have been eliminated?

[datzenmike]

'73/'73

 

'75 and up...

[Cardinal Grammeter]

I'll bet they did that to get that fan clutch in there.  The fact that they had the Tropical Fan suggests the initial setup was marginal as far as cooling.  I wonder if anyone has ever seen a Tropical Fan?

 

Here is a pic of the L20B radiator and shroud in my 74:

 

[datzenmike]

It's a truck. Many have put L20Bs in on an L16 radiator and cooling to spare but might be different if a working truck.

 

Tropical we wouldn't get. Central America, maybe Hawaii and Philippines and like I said maybe just extra blade.

[bilzbobaggins]

Wouldnt the tropical  assembly be for a J series motor?

[datzenmike]

Something so small and under powered it can't over heat?

[Cardinal Grammeter]

On 9/14/2021 at 2:26 PM, datzenmike said:

 

'73 shroud is 21475-B5500

'74 shroud is the same just a superseded B5500 to B7900 number.

 

The difference between 330mm and 350mm is only a cm around the fan and the hole opening. The opening is never going to be 330mm and 350mm and is probably 400 or more to allow engine movement so 1 cm isn't going to preclude using the one shroud.

 

 

There is a guy selling a "L16/18 Shroud" in Australia (link below) for something like $75 shipped which isn't that bad.  However in the description he states the diameter of the opening as 35 cm which results in zero clearance with the L18 350mm fan diameter.  But does the fan actually fit in the hole or is it completely "out of the hole?"  If the 330mm L16 fan is in the 350mm hole, wouldn't a broken motor mount damage the shroud/fan?

 

It also looks like the shroud is much shorter (stays closer to the radiator than the L20B shroud):

 

 

 

Copied and pasted from the ad:

 

BRAND NEW

NISSAN DATSUN 620

L16 / L18 ENGINE

RADIATOR FAN SURROUND/SHROUD

 

35cm DIAMETER HOLE

25CM SHORT HOLE CENTRES

47.7CM LONG HOLE CENTRES

 

Here is the link which won't last forever:

 

https://www.ebay.com/itm/144038717886?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Db6e8ec4e1fdc4194bc9b1d3c8f44e845%26pid%3D100675%26rk%3D5%26rkt%3D15%26sd%3D133753324661%26itm%3D144038717886%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A9144f79e-167a-11ec-801b-5a5d18c4898a|parentrq%3Aebbcc47017b0a7b8bc868b3ffffea4f4|iid%3A1

Edited September 16, 2021 by Cardinal Grammeter

[datzenmike]

Ideally just inside. If blade is too inside or outside the shroud, efficiency is lost. Air will form vortices like a plane wingtip and the high pressure side will slip around and try to cancel the low pressure side. You have a Dremel?

 

I've used shrouds that were two piece. Top and bottom

[Cardinal Grammeter]

Grinding is always an option.  But if there is only one L16/18 shroud and its opening is 35cm, how can that be proper for the 350mm L18 fan?  I've measured my fan and it is basically 14"  Are you absolutely sure there is just one shroud for the L16 and l18 - that those 2 part numbers are the same part?

[datzenmike]

Now not sure.

 

Fans

21060-A4600 is 330mm  to 09 '73 so presumably L16 on the 620

21060-A4600 is TROPICS 330mm  to 09 '73

21060-U2000 is 350mm 10 '73 t0 08 '74 so for the '74 model year.

All L20B were 7 blade 380mm and clutch fan

 

Shroud

Different number for the '73, '74 and the '75 and up L20B

L20B and '80- Z series

 

 

 

 I found a 4 blade 33cm and a pair of 7 blade 38cm laying around.

[ducky]

im thinking about doing something stupid and printing an adapter to run the slightly larger fan on my stock l20b. its dark now, so i cant (dont want to) go out and measure. do we KNOW the diameter of the hole for the l20b shroud?

[ducky]

Ok, well I went out and measured as best I could without taking it out of the truck and whatnot. Looks like right around 17", so probably 430-435mm? With the fan I ordered, which is supposed to be 410mm, is that enough space without cutting or removing the shroud?