Restoring the 280Z EFI Fuel pump (if possible)

[EuroDat]

A while back I cleaned my 280Z fuel pump and replaced the o-rings. Its running ok and I compared it to an old reserve pump. The reserve pump delivered about 75% of the flow compared to the one in the car.

Since these pumps are getting harder to find in good condition I decided to take a closer look at the spare pump. The outside looked shocking, corroded and rusty so I cleaned and painted it to make it look respectable.

 

After opening it up Im wondering it was worth the trouble cleaning and keep it as an emergency unit. The inside is showing a lot more signs of wear compared to the one in the car.

 

There are possabilities to improve it. I was thinking of making a new center section (intermediate part) and maybe new rollers. The inner ring of this part has vertical lines which reduce performance some and make it noisy in operation. These parts are made from hardened steel, maybe steel type S890 (890MPa tear strength) would be suitable. Not sure what it would cost to make.

The inlet end plate could be surfaced 0,1mm to remove most of the wear. That would increase the crush on the o-ring, but it should be ok.

That should improve the output and reduce the noise a little.

 

Opinions welcome.

 

Here are some photos of the worn parts and a drawing of the part for possible replacement. 

PumpRing1_Rev0.pdf

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Edited July 18, 2015 by EuroDat

[Chickenman]

I think it would be worthwhile rebuilding this as a spare pump. The end plate can be lapped to remove the wear marks no problem.

 

On second thought. Let me go downstairs and check the shelves. I may still have my old pump there. Center section was in good shape as I recall and so was end plate. Motor was shot but rest of pump was good. 

Edited July 20, 2015 by Chickenman

[Chickenman]

Dang.... Have the old pump and everything is in excellent condition, virtually no wear.. except I dropped it and knocked a big chip out of the center section right where the O-ring seats. Sorry.....   

[Chickenman]

You should be able to lap both the end cap and the motor plate to eliminate the wear marks.

 

Edit: The Z Car Depot has new pumps for $269 USD. That's cheaper than other vendors have which range from $450 to $750.

 

$269 is not bad for these pumps if you require the OEM Jeco pump for restoration purposes. Otherwise I would just install an aftermarket Turbine style pump like an Airtex E8312.

 

Here is the link to the Jeco pump for $269 USD. They ship WorldWide:

 

http://www.ebay.com/itm/Datsun-280Z-280ZX-1975-83-Fuel-Pump-Fuel-injection-OEM-Genuine-NEW-/321802193884?fits=Make%3ANissan|Model%3A280Z&hash=item4aece7cbdc&vxp=mtr

Edited July 20, 2015 by Chickenman

[siteunseen]

Here's some info from Blue on atlanticz;

 

http://atlanticz.ca/zclub/techtips/fuelpump/index.html

[EuroDat]

Dang.... Have the old pump and everything is in excellent condition, virtually no wear.. except I dropped it and knocked a big chip out of the center section right where the O-ring seats. Sorry.....

Well at least Im not the only one that does that kind of thing. A couple of weeks back I was cleaning my ballast resistor and it looked like new for about 20seconds until I dropped it and it shattered.

What are the rollers and impeller like? This one seems worn when I compare it to the phots on Alanticz and from memory of my in car unit.

I would like to keep the original style. Thats why Im tinkering with this one. It works, but it sounds awfull and it doesn't pump as much as the one on the car now.

Here's some info from Blue on atlanticz;

http://atlanticz.ca/zclub/techtips/fuelpump/index.html

Site, Thanks, I have read just about every page on Blues Atlanicz site. Its an ecellent source of info. The tech tip on these pumps is more external and replaceable things like o-rings. My problems with this pump is its worn out. Really no other word for it. Thats why I thought Id play with it a little, if I stuff it up no loss and I can always go aftermarket with the Bosch pump.

They use them here a lot on the old BMW, VW, Alfa and porches etc with the bosch J jetronic systems. Bosch still make them in the Cheq republic I think.

The maximum pressure is a little higher than the original, but that is controlled by the FPR. Google this part number 0580254984 and you will find them easy enough.

http://www.ebay.com/itm/Bosch-0580254984-POMPA-CARBURANTE-ORIGINALE-Volvo-240-turbo-Porche-911-/371382769888?pt=LH_DefaultDomain_101&hash=item56782358e0&vxp=mtr

http://www.amazon.com/dp/B001CO2LI2/ref=as_sl_pd_tf_lc?tag=boschfuelpumps-20&camp=213381&creative=390973&linkCode=as4&creativeASIN=B001CO2LI2&adid=18GFZW2S9TJX21X6FHXH&&ref-refURL=http%3A%2F%2Fwww.boschfuelpumps.com%2F

Edited July 20, 2015 by EuroDat

[EuroDat]

This all started because I was curious why it was making so much noise and performing so badly, but now I think I may have a real chance of improving it.

 

I cleaned up the pump motor end and inlet part today. The first problem was I couldn't think of a way to work the motor end without getting a lot of fine material in the motor. Then I thought of trying grease to fill the holes and later flush it out by pouring fuel in from the outlet end through the motor. It seemed to work ok.

Next I sent the drawing of the center ring and the rollers to a machine shop that does work for us. It will be interesting to hear what it will cost to make.

 

In the mean time I will assemble the pump and do a free flow and pressure test to see what the rework has done to its performance. This pump barely making 3.3 (48psi) compared to the other pump making 3.7Barg (54psi).

 

Here are some before and after photo's

 

[Zed Head]

Doesn't the internal relief valve determine maximum pressure?  Both of yours are in the range.  Flow rate at a set pressure might be a good measure of wear though.

[EuroDat]

Doesn't the internal relief valve determine maximum pressure?  Both of yours are in the range.  Flow rate at a set pressure might be a good measure of wear though.

Thats true. I forgot about that really wide tolerance for the pressure relief valve.

The pressure wasn't worrying me because it was above the 36psi FPR maximum. Its the noise it making when its running at that pressure. I think the vertical lines in the ring and causing the noise when the rollors move over then. Its a lot noisier than the one in the car.

 

I found an old photo of my good pump to compare with these rollers. There is a lot of wear on them judging by the photo. These measure in at Ø4.5mm and Im wondering if they were more like Ø5.0mm when new. I can't confirm that just assuming.

The groove is 5.4mm wide which give 0.9mm clearance.

[Chickenman]

I just measured my rollers and impeller. Rollers are 4.98 - 4.99 mm and impeller is 5.34 mm. Clearance of .35mm

 

Richard

[EuroDat]

I suspected they would be 5mm. Thanks for taking the measurements.

Looks like Ill be up for a new set of them too.

[EuroDat]

Pulled the pump out of the car today to compare the internals.

It also has a small leak around the terminals. More notacable in cold weather because the fuel doesn't evapourate so quick and you can see a dip hanging from the terminals.

 

I will start calling them 280ZX (Spare) and 280Z (in car) pumps because they seem to have increased the capacity in the later model. The impeller, rollers and outer ring are 7.5mm in the 280ZX pump and 7.00mm in the 280Z pump.

 

The inlet screens are not interchangable. The 280ZX screen is 1mm bigger than the inside diameter of the 280Z inlet.

 

I am now thinking of swapping the impeller, rollers and outer ring to make one good pump. That would be the 280ZX motor and inlet coupled to the pump middle section from the 280Z pump. After the holiday break Ill try to get a ring and rollers fabricated the spare unit. That will depend on price.

 

Here are some photo's of the parts.

1st row: Rollers showing worn 280ZX roller

2nd row: The outer ring thickness differences. The 280ZX is 7.5mm (0.5mm thicker)

3rd row: Roller length and the inlet filter screen. Won't fit the 280Z without force.