Fuel pump leaking

[J's 620]

76 620 l20b, basically stock motor with a 2” exhaust system. I put in a Weber 38/38, runs great, but I noticed the fuel pump started leaking from what appears to be a hole on the underside of the pump. A pressure relief perhaps? I’m not running a regulator and I think this is why it leaks now. Anybody else run into this issue?

[datzenmike]

The mechanical pump is self regulating and works just fine as is.

 

They are very reliable and I have never seen a failed one though I'm sure that this could happen. Get a used one from a wrecking yard if you want good quality, or try a want ad... https://ratsun.net/classifieds/category/9-datsun-parts/  .... New from Nissan they are about $100 so $50 would be about right from an auto parts store. You get what you pay for so don't expect much from a $20 POS. If you go electric you want not much over 3 to 3.5 PSI and best to mount it low and as close to the tank as possible and put a filter before it or replace the one you have if you replace the mechanical one.

[banzai510(hainz)]

Mike

I haven't heard of to many Datsuns in the junkyard. they crush them in a week up here in seattle as nobody looks for parts from these.As Datsun people don't want to pay!!!!

 

if they leak out the vent then the diaphrame is leaky and you might even have gas in the oil. so cheack that out. Maybe change your OIL

 

there is the Blackstone Mexico GOLD cap fuel pumps and some Chinese knockoffs that look like stock Japan made units.  usually under 30$

Maybe the dealer has some for about 120 if not more.  I still run Koyosan units and have 1 last spare when they were cheap.

 

One can go electric but needs to be under 4 pounds. Better yet like 3pounds.

Edited June 3, 2020 by banzai510(hainz)

[J's 620]

I’ve never had issues with my pump, it’s a factory part, I just can’t wrap my brain around why it leaks from this little hole. I will try to post a pic. Thanks for the replies. It didn’t appear to have gas in the oil. 
 On another unrelated note, I’ve had to reset my password twice today just to log in. 

[datzenmike]

My price list is from 2004 ish and it might be in CDN moneyz.. Ninety-eight seemed a little low. Are they around $120 US down there if dealer has one.???

[banzai510(hainz)]

vent hole is for movement or air in a contain space.

Diaprames wear out and crack  just the way it is if one own a Datsun long enough. Datsun don't need a lot of gas so long as there is a vacuum to suck the gas it will work but mess up the engine bay and maybe suck gas in to the crank case

Edited June 3, 2020 by banzai510(hainz)

[J's 620]

Hmmmm, interesting point. Yeah only thing I changed was a carb and fuel lines. I kept my pcv, ran the cam cover vent  to the provided hole in the air cleaner housing. 
 Mike, i would have to call the dealer to see what a price would be. 

[J's 620]

Maybe swapping to the Weber was the straw that broke the camels back. Maybe the diaphragm gave. 

[datzenmike]

The fuel pump doesn't care what carburetor it's feeding. It's only job is to push gas at 3- 3.9 PSI and at 1,000 RPMs, deliver 1 liter or more volume. More than enough gas for any carburetor and the engine. If the diaphragm is leaking then it just normal wear that added up.

[J's 620]

So the consensus is, get a new fuel pump. Well I suppose it lasted long enough! Thanks guys. Now the decision of electric or mechanical. But that’s a topic in itself. 

[datzenmike]

Check around for a rebuild kit on line.

[Pacific coast Datsun]

2 hours ago, J's 620 said:

So the consensus is, get a new fuel pump. Well I suppose it lasted long enough! Thanks guys. Now the decision of electric or mechanical. But that’s a topic in itself. 

If your running a factory Nikki fuel pump they do sell rebuild kits. Keep it factory if you can.

[difrangia]

RockAuto.com

 

Cheap enuf that you can buy an extra and put in the stash

 

https://www.rockauto.com/en/catalog/nissan,1978,620+pickup,2.0l+l4,1210149,fuel+&+air,fuel+pump,6256

 

[banzai510(hainz)]

This is a 510 one Im sure its China, I bought 2 myself But someone on here is using one. this is close as orginal as one can get but the intake and out pipe are for a 510. where they located.

But if one can find a rebuild kit for your old one that's good to But make sure Made in Japan otherwise could be a kids Bike innertube as a diaphrame made in Vietnam/Bamgladesh

 

 

https://www.rockauto.com/en/moreinfo.php?pk=296166&cc=1209978&jsn=361

[datzenmike]

If $8.99 then definitely Chinese. You can remove the 10? screws on the top and clock it to aim the inlet/outlets to better locations.

[J's 620]

This 620 doesn’t actually have the pump with bolts on the top, It’s a solid unit, so maybe it’s not a factory part then. Anyway my local Napa has the fuel pump in stock and I can pick it up tomorrow for $45. 
 I know it’s been suggested to go electric but I’d like to keep most things stock or close to it. 
 As far as junkyard Datsuns......probably non existent here in East Idaho. I haven’t seen anything in awhile. Thanks for the advice and replies fellas, I will post up the results when I replace the pump. 

[J's 620]

NAPA did NOT have the part today. The fool on the phone must have thought I was asking for an electric pump, a universal type. I should have specified, so shame on me. 

[datzenmike]

On 6/3/2020 at 5:39 AM, J's 620 said:

...started leaking from what appears to be a hole on the underside of the pump....

 

Can't say I've seen a hole on the Datsun pumps.

[Leo92335]

I installed a Webber and I'm running an electric pump from summit racing and it works great and I do have a regulator, Webber requires no more than 2.7 psi so if your pump is more than that you will have a problem,my pump is a low pressure pump between 2.5 and 4.

[J's 620]

It’s not a good picture, but this hole has to be the leak. The fuel was dripping from this area. This fuel pump does not have the screws in the top. 

[J's 620]

I’m curious, why go electric though? 

[datzenmike]

Definitely not the Hitachi that Nissan used. I've seen these before and are a regular replacement pump.

[banzai510(hainz)]

That’s a cheap aftermarket pump in the photo

[J's 620]

Well I ordered my pump from a 75 620. It’s the rebuildable type, has the correct inlet/ outlet locations, and it went in smoothly. The truck runs great no leaks. Problem solved. I hope this pump holds up for awhile.