Rebuilding The Nikki Fuel Pump

[motivealloy]

Hey gang,

 

I am going to share with you what I've done to rebuild a 240z fuel pump with great success. This is also (for the time being) an inexpensive solution to rebuilding an original Nikki 240-260Z mechanical fuel pump.

 

What I have learned so far is; rebuild kits for our old fuel pumps have not been available in American for some time now. They are available in Australia and maybe Canada but importing them here isn't cost effective. Original NOS 240Z Nikki fuel pumps are extremely expensive, and the aftermarket fuel pumps look like crap. There are electric fuel pumps available cheap but they require wiring and fuel pressure regulators and I think they are unsightly.

 

My background is in international manufacturing. The one thing i know about intl mfg is that a lot of parts suppliers HATE making 10 or 15 versions of the same damn part. So what they implement is, what is called in the manufacturing industry as, "part uniformity" or "part sharing". The term is exactly as it implies. Multiple similar items will share some of the same basic parts. This cuts down on overburdening the manufacturing process. It is far more cost effective and easier to pump out 100,000 of the same part than 1000 each of 100 slightly different versions of the same part.

 

Japan is notorious for using this philosophy in it's auto industry. It was only about 10 years ago that US auto makers adopted part uniformity in their assembly lines.

 

Okay, with that being said I began to do a little research on our Nikki fuel pumps. And voila, exactly as i suspected!! Nikki used the same exact castings and rubber gaskets in it's fuel pumps it supplied for many models of Datsun autos.

 

What am I getting at with this primer you may ask? Simple, Nikki fuel pump parts from different cars are swappable.

 

Here is a photo of an NOS 240Z Nikki fuel pump. They cost about $175 to $225 for an NOS example.

 

 

Here is a Nikki fuel pump for a Datsun F-10 wagon next to our original "leaking" Nikki fuel pump. These cost about $25 to $60 for an NOS example.

 

 

Notice that the F-10 and 240Z fuel pumps both have 271070 part numbers cast in the side. This number signifies the type of internal mechanism and components of the fuel pump. It is NOT the part number for a 240Z fuel pump as I have read elsewhere. A Nikki fuel pump from an F-10, 610, 710, 620, 510, 210, B210, 310, 240Z, 260Z all use the same fuel pump internal parts. Only difference between the pumps is the lower body casting (240z has three bolts to secure to engine the other only has two), actuator lever shape and size, and the fuel inlet location.

 

 

The upper castings are the same on both fuel pumps. Except for where the fuel lines are tapped.

 

TIP: Make sure to have a complete complement of flat blade screwdrivers handy. I used at least three different thickness of blades dismantling the fuel pump. Loosen all of the screws on the fuel pump while the fuel pump is bolted to the engine. This allows you to get much more torque on those stubborn screws. AVOID using a Philips head at all cost. They tend to strip out the screw heads very easily.

 

 

The main fuel diaphragms are similar in construction. The newer one on the right is a better design. It has two membranes sandwiched together instead of one thick one like our original had. And the spring retainer cup holds the pump spring more secure. Notice that the tab that fits under the actuator arm is not the slotted style like what you would find on a rebuild kit. You will have to remove the fuel pump from the engine block to wiggle the diaphragm out. It's fairly easy. Just push down and slide the diaphragm housing away from the actuator lever.

 

 

Dual diaphragm design.

 

 

Upper casting with same internal fuel valves. New one is on the left. I didn't swap these parts out as the screws were stuck and I didn't want to damage anything. Also, the valves were in great shape so really no need to swap them.

 

 

 

 

cont...

[motivealloy]

...part 2 cont.

 

Inside the top of the casting. Notice that the 240Z casting has a little "SD" icon cast into it where as the F-10 pump lacks this detail. Identical casting otherwise.

 

 

Here is how you swap the lower oil seal. Just fit a thin flat blade screw driver under the lip and pry up. 

TIP: Make sure to place a rag over the top when you do this as the pressure fit retainer clip will shoot out a few feet from where you are working. You can see that the retainer is already removed from the pump on the right.

 

 

Oil seal comparison. Our old one on the left was torn and becoming brittle.

 

 

Swap out the oil seals and replace the retainer by taking a socket about the same size a the inside of the retainer and tap it back in with a hammer. It might take a few times as the retainer wants to slip around. I had a helper when I did this operation. Line up the peen marks if possible.

 

 

Install the diaphragm opposite how you took the old one out. You install the end of the rod diagonally so it can fit under the actuator arm. You may need to move the actuator arm down to allow the rod end to clear. It should pop into place.

 

 

Install the pump back onto the engine block at this point. It's way easier this way trust me.

 

 

Reassemble the upper casting using the bright new screws, top cover plate, and gasket from the new pump. Then screw the rebuilt fuel transfer housing onto the diaphragm base using the rest of the bright new screws. Reattach hoses and such.

 

TIP: I did swap out the fuel inlet tube as the original one was much shorter and had a thinner OD tube diameter than the one from the F-10 pump. You may need to temporarily bolt the fuel transfer housing to the engine block to get enough torque to unscrew the inlet tube. These have tapered threads so they will seal against fuel leakage. No need to use plumbers tape or any sealer. The more you screw on the threads the tighter it will get.

 

 

Crank up the engine and look for any leaks.

 

All in all this took us about an hour to do and only cost me about $30.00. How awesome it that!!

[grannyknot]

Pretty awesome, nice write up.

[Darrel]

http://www.new-datsun-parts.com/datsun-240Z-parts-exterior2.html

[240260280z]

genius!

[siteunseen]

Thank you for that.  I hate the way the generic UFO looking one I had to get looks.

 

Where did you find that new pump?  Do you have a Nissan number?

 

Thanks,

Cliff

[motivealloy]

hey thanks guys here are some quick replys:

 

Cliff,

Just look up "Nikki Fuel pump" on ebay. A ton will pop up. Just look for the right one at the cheapest price.

 

Darrel,

That website has the rebuild kit but after shipping fees are tacked on for Canada to US that $30 kit jumps into the $50+ range.

[rossiz]

love it - even tho i don't have a mech pump... always cool to see a clever work-around. well done.

[26th-Z]

Great write-up.  Thanks!

[pbarcher]

Steve and Robert,

 

Thanks for the thorough description of the process.  The engine from my 73 is being rebuilt at Datsun Spirit now, and after almost 42 years it seems prudent to rebuild the fuel pump too.  If I understand correctly, I need a pump with 271070 on the lower casting.  Correct?

 

How do I know if the a pump has the dual layer diaphragm that you illustrate?  Also, isn't it possible that the gaskets have dried out, or may tear when disassembling the NOS pump?

 

Peter

[jfa.series1]

Great write-up.  I spotted a used 240Z Nikki pump on eBay for $30 and quickly snatched it.  I just ordered the rebuild kit and am looking forward to another project.  Thanks for posting all this info!

[motivealloy]

Hey Peter,

 

Yes that is correct. Just look for Nikki fuel pump on ebay. The Nikki fuel pump from an F-10, 610, 710, 620, 510, 210, B210, 310, 240Z, 260Z all use the same fuel pump internal parts. The easiest way to tell if it has a dual diaphragm is the little tab of rubber that sticks out the side of the pump will have a tiny staple in it. You can see it in the photos i posted.

 

The rubber gaskets shouldn't be dry as it's been sitting on a shelf.