L series Water pumps and fan clutches.

[dimedriver]

I have an L18 in my 74' 620. It cam with a fan bolted straight to the water pump pulley no clutch. I picked up a clutch and fan from the junk yard off of a Z car Thinking they were all the same.

 

So I found that the Z car has the four bolts on the fan assembly spaced just a little wider.

 

I was wondering if I could just pick up a new water pump for say a 280zx and swap out the old one? I don't think its bad but I also just got the truck. I was thinking of getting the Beck/Arnly one from rock Auto. BECK/ARNLEY Part # 1310416

 

I already have a pulley with the correct spacing left over from a Z. It also seems to be the same height.

 

I know if I do get a pump I need to look for the cast vs. the crappy stamped impeller.

 

Am I going to to run into spacing issues where the pully is now further forward or will it be the same?

 

-dimedriver

[dimedriver]

So, am I totally off my rocker? Or is this justing going to work?

I would like to order my parts soon.

 

-Avery

[hang_510]

ive seen different bolt spacing for fans for the L series, they should be identical.

 

if the pulley matches, then the fan will need some filing to fit, all 4 holes need to be adjusted the same.

 

get a cast pump if avail.

[datsunaholic]

It's not going to work. The Z type water pump/clutch fan/fan assembly is going to be too long and hit the radiator. Plus the pulley spacing might be different.

 

The '75-79 water pump with clutch might fit but it'll be close. The '75-79 620 had the core support moved forward a bit for clearance. But if you use that setup, you need the matching fan. They're all different. There's the no-clutch fan, the "flanged clutch" Z-car fan, the small-clutch truck fan, and the large-clutch "car" fan (with the small and large being usually misrepresented as A/C- non A/C water pumps). There's also a large-clutch truck fan with different offset from a NAPS-Z 720.

[dimedriver]

Thanks, whats the take on the flexible bladed fans? Sounds like this would be a more straight forward fix to replace this sold plastic clutchless kludge thats on there now.

[hang_510]

i have a stock 4 blade plastic fan as it the only that fit. :lol:

 

 

i like the flexi fans though, got one for the wagon.

[Z-train]

It's not going to work. The Z type water pump/clutch fan/fan assembly is going to be too long and hit the radiator. Plus the pulley spacing might be different.

 

The '75-79 water pump with clutch might fit but it'll be close. The '75-79 620 had the core support moved forward a bit for clearance. But if you use that setup, you need the matching fan. They're all different. There's the no-clutch fan, the "flanged clutch" Z-car fan, the small-clutch truck fan, and the large-clutch "car" fan (with the small and large being usually misrepresented as A/C- non A/C water pumps). There's also a large-clutch truck fan with different offset from a NAPS-Z 720.

 

No "mis-representation" going on.The large clutch 620 fan(and you are right-the Z-car unit won't work as the pulley depth is wrong)is what is called for at the parts counter when FACTORY A/C is used.The small clutch was used on all non-A/C trucks including the ones with after-market A/C.

 

I just went thru this song & dance last week.

[datsunaholic]

I'd agree with you, Ztrain, except that I've owned a lot of trucks that had and didn't have factory AC. Every one had the small fan clutch, using the small-clutch fan bolt spacing. I suppose it's possible that somone bought the wrong water pump, but then they had to change the fan too. I guess that it's quite possible that in my travels I've just never actually seen a 620 with a large fan clutch.

 

My '78-81 510s, which also are marked as no AC/factor AC being different all use the large-clutch fans.

[datzenmike]

There's also a large-clutch truck fan with different offset from a NAPS-Z 720.

 

Doug, I'm fairly sure that the NAPS clutch fan and integral fan will fit the L series with no offset problem. I'll check when I get home but the NAPS plastic fanbolt pattern is a larger diameter to match the larher diameter NAPS clutch unit. The NAPS pump itself also has a larger internal vane and deeper cavity to contain it. Looks the same on the outside as the 620 pump other than the fan.

[datsunaholic]

Hmm, maybe, but I was having issues matching a Z24 engine with a '81 510. The '81 510 fan fit teh clutch, but it hit the Z24 crank pulley. One too many rows. The Z24 fan, was too close to the radiator.

[Z-train]

1)620 non-A/C & dealer A/C- small clutch mated to pulley/waterpump.7 bladed fan.

 

2)620 factory A/C-large clutch(L-24 size)mated to pulley/waterpump.L-24 8 bladed fan will fit but not the factory shroud.Misses by about 50 mm.

 

3)L-24-seperate clutch/fan & pulley

 

1)Should be sufficient

2)What changed with the installation of the larger clutch/pump?Did the fan change or did they use the L-24 fan and change the shroud dimensions?

3) Not gonna work on a L-16,18,20b due to pulley depth & fan shroud issues.