'81 510 Wagon Mechanical Fuel Pump

[spoiledmilkwagon]

Hey guys,

 

As the title states, have an 81 510 wagon, has the z20s engine. Recently noticed my factory "Atsugi" 6-screw top style mech fuel pump leaking fuel from the diaphragm vent on the bottom, indicating I have a hole in my diaphragm. I am willing to rebuild the pump if someone can point me in the direction of a similar pump or rebuild kit. My question, though, is this: On the internet, I see stamped/pressed together style pumps for later model year 720s with the z20 engine that are readily available. They appear dimensionally similar. Can I use this pump on my 81 z20 in place of the screw top pump? Any advice or direction would be great. Thanks.

[banzai510(hainz)]

ebay has Japan made NOS pumps.

match the inlet out let ans should be fine

[datzenmike]

Pressed together? I don't care for then or their looks.

 

 

There were two sizes of pumps, with the larger used on the Z22 in the 720. I assume all L20B and Z20S (2 liter) engines used the same smaller pumps, why not?

 

Small

The Z20S in the A10 isn't listed but the L20B one IS for the year before. 17053-N8200

The L20B in the late '79 620, '79 200sx,  is 17053-N5810. Different number may just be a different material used

 

Large

The Z22 in the 720 uses 17053-05W10. (possibly used on the Z20, I don't know)

 

Measure the diameter of the fuel pump and post this. The Z22 pump is very noticeably larger.

 

[Stoffregen Motorsports]

I wonder if rebuild parts are still available. What's in there? A diaphragm, a spring, maybe a seal or two...

[datzenmike]

Couple of one way valves.

[spoiledmilkwagon]

Id much rather find a diaphragm to replace the one I have. I just cant seem to find a straightforward p/n on a replacement. I'm out of town the weekend so I cant measure that pump. I've looked at the l20b pumps and they seem to be the same except for the diameter of the top "4 bolt" cover compared to my "6 bolt" cover and the position of the fuel inlet and outlet. They also lack a fuel return line.

 

This is a $400 car, I dont necessarily care about having true japanese parts or how they look. Just care that its dependable. Thinking about throwing this one on it and calling it a day.

https://www.ebay.com/itm/285252274842?fits=Year%3A1981|Make%3ADatsun&hash=item426a5c4a9a:g:eSYAAOSwt3lkWVR8&amdata=enc%3AAQAIAAAA0ACFstHvbI1R0UE7ML6fMQYg9qb1Thcw8GJPfoWOkw8XIpb%2BjU86oASGrZRw5obwOTK38xc%2BqA%2BZNs2e81UdsmND3ctPy6tJCuCIYYPoX1Pw1kvOVHjUcOZJdMbxkSUQcBW%2BaDS5sT2U%2BM9irHaIaJ5%2BzeoSbDcAjqyee%2B11q7wSKst8I7jcV%2Bm0tzwBIoEp7ArkhReocibKTbVad%2B8BPz3Zmm7SpbzHFyTLRaHsqe3rPbC9SudS17pp3TFrYCZVZYZuzOstsysk0QoUm%2FWivDw%3D|tkp%3ABk9SR6yM-sLcYg

[datzenmike]

The return line isn't on the pump it's on the hard line to the carburetor.

 

 L20B carburetors are on the left side of the engine and the pump outlet points across the front of the engine to the left side. Z series engines have the carburetor on the right side so the pump outlet points to the rear down the right side.

 

My info seems to suggest that the Z20S in the A10 is a 4 bolt pump same as the earlier L20B, so yours may have been swapped? So it would be off a 720 Z22 engine likely. I'll wait till you measure the size to confirm it's the larger of the two pumps. Now THAT pump I have a part number for.

[spoiledmilkwagon]

Very well could have been swapped by the PO. I'll get you those measurements ASAP. Thanks Mike. 

[Stoffregen Motorsports]

13 hours ago, spoiledmilkwagon said:

Id much rather find a diaphragm to replace the one I have. I just cant seem to find a straightforward p/n on a replacement. I'm out of town the weekend so I cant measure that pump. I've looked at the l20b pumps and they seem to be the same except for the diameter of the top "4 bolt" cover compared to my "6 bolt" cover and the position of the fuel inlet and outlet. They also lack a fuel return line.

 

This is a $400 car, I dont necessarily care about having true japanese parts or how they look. Just care that its dependable. Thinking about throwing this one on it and calling it a day.

https://www.ebay.com/itm/285252274842?fits=Year%3A1981|Make%3ADatsun&hash=item426a5c4a9a:g:eSYAAOSwt3lkWVR8&amdata=enc%3AAQAIAAAA0ACFstHvbI1R0UE7ML6fMQYg9qb1Thcw8GJPfoWOkw8XIpb%2BjU86oASGrZRw5obwOTK38xc%2BqA%2BZNs2e81UdsmND3ctPy6tJCuCIYYPoX1Pw1kvOVHjUcOZJdMbxkSUQcBW%2BaDS5sT2U%2BM9irHaIaJ5%2BzeoSbDcAjqyee%2B11q7wSKst8I7jcV%2Bm0tzwBIoEp7ArkhReocibKTbVad%2B8BPz3Zmm7SpbzHFyTLRaHsqe3rPbC9SudS17pp3TFrYCZVZYZuzOstsysk0QoUm%2FWivDw%3D|tkp%3ABk9SR6yM-sLcYg

Ok, understood, but don't throw those original parts away. They are rebuildable and someone might want it. Even if parts aren't available now, if the interest is strong enough, the aftermarket might fill that gap someday.