Rebuilding The Nikki Fuel Pump

[Stanley]

Do the inlet/outlet fittings screw in on that one? If so it's different from the stamped steel ones I've seen.

 

Googled Import Direct FP's, some problems reported.

[siteunseen]

Do the inlet/outlet fittings screw in on that one? If so it's different from the stamped steel ones I've seen.

 

Googled Import Direct FP's, some problems reported.

Nope, they're pressed in too.

I'm going for dependable pressure and getting an electric one.

[Captain Obvious]

Careless, I wasn't proposing to push the balls through. I know that won't work because of the step in the id (it's known as a counterbore).

 

I was just musing some ways to PULL the balls out because, by design, pushing them through simply cannot succeed. The suggestion of heat would make it easier to pull the balls OUT if you could get a grip on them. I mean... Yes, there's a slim to zero chance that heating the housing and then rapping it on a hard surface might knock the ball out of the hole in which it's pressed into, but very slim chance. Sure, I'd try  it, but I would be more surprised if it would work than if it would fail.

 

And as far as if the balls are hardened or not, just because they didn't deform isn't really a true indication. Again... slim chances that they are NOT hardened, but anything is possible. If the balls are hardened, you might be able to drill through them with a carbide bit, but it's not as easy as it sounds.

 

Other ideas?

 

If I had two pumps, I'm confident I could salvage the arm from one of them and the body casting from another. Then I could put one pump back together using a different (removable) means to hold the arm in place and seal the holes.

 

You might be able to weld a stub to the ball and use the stub to pull the ball out. The heat from welding might also temper the balls to make drilling easier. Temper the balls. Just felt the need to say that again...

[Careless]

Sorry, I thought you meant heating the housing and pushing them through- passed the ID step. But now I gather that you mean heating them up and letting them fall out or something like that. I think that may have worked better, but I had pressed the balls further in from the get go, thinking it was just a nicely formed pin with two rounded ends.

 

Welding, drilling, or heating would have been a great idea... If it were in the original position. Now that I know how it's made, I would have forced some 309 filler rod on the ball while TIG welding it to the ball and then let off the arc slowly to let the filler wire stick to the bearing and then yank on it. That would probably worked amazing. But that only works if you don't press the ball bearings in first. They go pretty far down in there... too far to use any large TIG cup or filler rod. I think the only way I would have gotten that done was to use some extremely small arc-rod and wrap the OD of the rod with something as an insulator to just stick it in there and press it really quick to fuse it, and then cut the power to the welder or remove the ground. I've had success doing that with broken bolts in blind holes. 

 

Alas, it was too late at that point. I had to remove the pin so I tried the most "common" method. I had a feeling it wouldn't work. Next time I will listen to my inner voice a bit more. .

[siteunseen]

 Temper the balls. Just felt the need to say that again...

When my balls get tempered I have to tuck them into my socks. 

[Captain Obvious]

So you've clearly got the welding part down and have used it on busted bolts and the like in the past. Only problem is you didn't know what you were dealing with. Now we both know. And I thank you for the info in case I ever find myself in a similar situation. It's always easier to take the SECOND one apart!

 

Alas, it was too late at that point. I had to remove the pin so I tried the most "common" method.

 

My mentors referred to that as the "Brute Force and Ignorance" (BFI) method and I'm quite familiar with that method as well. 

 

So one more detail about this stuff... You really only need to get ONE ball out the hard way. Because once you have one side out, you can press the other side out by pushing the pivot pin through the housing. So the job is really only 50% as hard as you might think, right?

 

When my balls get tempered I have to tuck them into my socks. 

 

Haha!! That happens when you get older, right?

[ccinnamon]

Thanks for the lesson on the fuel pump.   Very informative.    Was there a reason you did not just try to rebuild the old one?   I have a 72 240Z and for some reason the pump is not pumping.   Car has sat for about 8 years,.   So i assumed the diaphragm had gone bad, but before i  tried to find a rebuild kit i decided to take it apart, while still on the engine.   All seems in good order for all i can see.   The pump is not leaking oil or fuel.   Just not pumping out fuel.   It did suck  fuel into the fuel filter??  MMmm   A complicating factor is that my pump is surrounded by the air conditioner frame, and i had hoped i could rebuild without having to take the car apart to get to the pump.   Any suggestions overall.,   Also any suggestions on rebuild kits?   

Edited November 14, 2015 by ccinnamon

[Patcon]

I have had valves get stuck in the fuel pumps if they sit for a long time. Open it up and make the valves are loose and the passages aren't plugged with gunk.

[TonyTomB]

On 29/12/2014 at 9:56 PM, motivealloy said:

...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!!

What a facinating and informative subject.For a few months now I have been trying to fix my fuel pump which is the "Ampco.G22 Pump" ., coming across this site I have now discovered how to do it. It is sat in pieces on my kitchen window sill and I have just sent for a simialer pump from the USA.Hopefully the diaphram will be the same as the one that I have taken out of my original pump.  I hope that the oil seal is as easy to take out of them both as the diaphram was.  I need to keep my 1974 Datsun 260Z 2+2 as original as possible having won many best in class and concourse shows with it.It is totally original and unrestored so originallity is important. May I again thank you for such a fantastic easy to understand article and wish everyone on this site a Very Merry Christmas and the Best of Luck for the coming year.

Kind regards.TonyTomB

[jfa.series1]

To update this thread even further, has anyone located a current source for the Nikki rebuild kits for any of the substitution vehicle models listed in #1?  I've surfed several of my popular sites, no joy.

[TonyTomB]

Hi again.  I have now purchased a simialer brand new pump on ebay from the USA. I hope the internals are the same as the ones on mine.If so I can swap them around then at least I will have some control over the originalty of my 260Z. The problem I may have is getting out the oil seal unless someone can give me advice on a easy way to remove it,or where I may get a new one probably would be better.  Grateful for any help I receive.   Kind regards to you all Keep ZZZZZZEding.TonyTomB

[Gav240z]

Hey Guys,

I just went and looked at the fuel pump on my 72 240z (Australian Delivered). It looks exactly the same as the "Nikki" unit, but instead the casting has "Atsugi" written on it. I've attached a photo (not mine but 1 on eBay at the minute).

Is Atsugi the same as Nikki in that the company name changed later on? Or a completely different manufacturer?

Edited January 2, 2017 by Gav240z