Fuel regulator

[DatMo]

So I've been doing some searching and I'm looking to get an electric pump that's gonna feed into a 40mm dual carbs. Dellorto's in specific. If anyone can give me an idea of what to order, I'd greatly appreciate it. I've rea that I need 3.5 psi but some say 4 and I'm not sure.

 

Please help.

[banzai510(hainz)]

I run stock Koyosan fuel pump  No reg. Have dual 40s

 

dual carbs ran on stock pumps all before electric pumps were common

[Stoffregen Motorsports]

Carter Rotary Vane pump for $65 - https://www.summitracing.com/parts/crt-p4070?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-carter&gclid=CMHbyKbdyM4CFYdafgod7XQPYg

 

Holley low pressure regulator $30 - https://www.summitracing.com/parts/hly-12-804/overview/

 

Best to plumb it with 3/8 hard line. Also, get a gauge so you know where the pressure is at. https://www.summitracing.com/parts/hly-26-504/overview/

 

Unless you're making 200+ hp with your L4, the stock pump is fine.

[racerx]

Call pierce manifold, they been dealing w this stuff

[paradime]

Carter Rotary Vane pump for $65 - https://www.summitracing.com/parts/crt-p4070?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-carter&gclid=CMHbyKbdyM4CFYdafgod7XQPYg

 

Holley low pressure regulator $30 - https://www.summitracing.com/parts/hly-12-804/overview/

 

Best to plumb it with 3/8 hard line. Also, get a gauge so you know where the pressure is at. https://www.summitracing.com/parts/hly-26-504/overview/

 

Unless you're making 200+ hp with your L4, the stock pump is fine.

 

This^

[MarkB.]

Don't do it.

 

I did.  Eventually pump and regulator became clogged with waxy build up from the 10% ethanol gas sitting when I couldn't run it regularly.

 

Replaced with a "stock" pump from RockAuto; added a fuel filter.   It hasn't missed a beat on two DCOE 40s on an L20b.

 

Save your money.   Repeat:  The most reliable Datsun is a stock Datsun.

[datzenmike]

When I got my 710 it had one of those cheesy replacement mechanical pumps on it. In a box in the back was a used stock mechanical pump. I threw the 'new' one away* and put the old one back on to see what the problem was. Five years later it's still there.

 

*As I have half a dozen around I wasn't worried. Have yet to ever replace a mechanical pump.

[DatMo]

So I've went with the electric one because I have those Chinese pos mechanical pumps that always go out and as far as future swaps, I'm happier with electric.

 

However I'm having a fuel problem. The pump is sucking and I can feel it when I put my hand on it. WITH THIS SAID no fuel seems to be leaving the tank. I've replaced all the lines on the tank and made sure everything was well clamped. I have no idea what the issue is at this point and its deeply overwhelming. I've used compressed air but I'm not sure what to do anymore.

The car has 5 gallons. The fuel pump is wired correctly and the pump is also facing the correct directions with in/out nipples. No idea what's going on here. The pump is right under the passenger seat in a 1972 510

[scooter]

Try and mount it as close to the tank as you can. I'm using one of those facet type thumper pumps and it seems to work great. No issues.

[datzenmike]

You checked that no fuel is coming out the fuel line at the engine compartment? before the fuel filter? If no fuel, it could be presumed that the fuel line is plugged or a hose kinked.

 

If positive it is not plugged, then perhaps the line between tank and pump is kinked.

[DanielC]

So I count five out of ten posts telling you to run a stock mechanical fuel pump.  This is the sixth one.   Trust me, there is a lot of years of experience with Datsuns in the above posts.

 

Is the gas tank clean?  I do not know about goons, but a 521 had a fuel pick up pipe that was sitting close to the bottom of the tank, and any gunk in the tank would collect in the opening, and restrict fuel flow.  In 45 years since it was made, chances are there is some crud in your gas tank.  Are the rubber hoses good?  They are 45 years old too.   There is a possibility any metal lines have could have pin holes, from rust in them.   Any hole in a fuel line on the suction side of a fuel pump will leak air, and no pump can work with that.

[Stoffregen Motorsports]

So neither the electric or mechanical pumps work? Obviously a blockage in the system.

 

Blow the lines out with air (be careful, as injecting compressed air essentially creates a very explosive mixture) and try again.

 

Did you say the pump is under the seat? Inside the car? I wouldn't run fuel lines inside the car. Too dangerous.  And which electric pump did you go with? All electric pumps are not equal.

[Lockleaf]

Perform one last test and it should tell you if you need to drop your tank and get inside it.

 

pull the line from the tank that goes in to the pump and put it in a gas can. Hold the can up as high as the tank sits in the car. If you get fuel pumping, you have an issue in the tank and need to take it out and get into it. If no pumping, pump problem.

[DatMo]

I literally pulled my tank out and ran compressed air through every hole inside the tank. I ran stock pump and the same exact issue occurred. I put gas treatment inside the tank as well. I replaced all the lines of the tank including the vapor ones as well.

I do not know what could cause a blockage at this point but I'm thinking I may need a new tank. Used an external source for gas and it worked fine HOWEVER when I blew air into the tank, there were bubbles. I'm coming to the solution that the tank itself has some sort of issue and I'll need to get it redone at a shop, I'm not sure.

[DatMo]

You checked that no fuel is coming out the fuel line at the engine compartment? before the fuel filter? If no fuel, it could be presumed that the fuel line is plugged or a hose kinked.

 

If positive it is not plugged, then perhaps the line between tank and pump is kinked.

i have a filter which is under my back seat under the car and before that is a filter which is around 2ft away from the tank itself but that isn't even getting fuel for the actual pump to push forward.

[datzenmike]

i have a filter which is under my back seat under the car and before that is a filter which is around 2ft away from the tank itself but that isn't even getting fuel for the actual pump to push forward.

If the filter is between the tank and the pump it may be the restriction. Gravity won't flow much, but compressed air will force it's way through and seem clear. 

 

Pumps are limited to the 14.7 (at sea level) air pressure. No pump in the world can lift a liquid more that about 30 feet vertically, it's how high 14.7 PSI of air can push a liquid up a tube with a vacuum at the top. Mount the pump as low and as close to the tank as you can to help it. If possible use a larger inlet pipe size.

[racerx]

Not sure why u need a fuel regulator, had webers, both downdraft and single sidedraft on datsuns and ole skool celicas and never had any fuel delivery issues.