Looks like my '72 Z (with Z Therapy carbs) is going to need a new fuel pump. Should I consider installing an electric fuel pump in lieu of the OEM mechanical? Does anyone know if there is a recommended electric for early Zs? What about a pump that is a good match-up for Z Therapy carbs? Many years ago I did experience some vapor lock & it's my understanding that electric pumps help alleviate this.

In doing some preliminary research, it seems that the general consensus is that the aftermarket mechanical pumps for early Zs are not that great. Therefore one should use an OEM mechanical pump if deciding to go that route. Availability?

So I'd welcome any thoughts, BTDTs, etc. In advance, Thanks.

Best to all,
Chris
'72 240Z

Any replacement pump you decide on should be a rotary-vane, rather than a diaphragm pumper. Much quieter, smoother, and more efficient.

The electric pumps use less engine horsepower to operate than the standard mechanical pumps do. The electric pumps take their power from the alternator, rather than mechanically from the eccentric at the front of the cam. Never send a metal piece where you can send an electron.

Bryan Little's DATSUN Z GARAGE had a good section and advice concerning fuel pumps, but he has sold his Z, become inactive and closed his website.

Frank

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1970 240Z

Thanks for the reply & info Frank. I recall Bryan's website, referred to it many times. Any way to resurrect the fuel pump info from the website?

Best,
Chris

I'm looking.......

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1970 240Z

Pssst Here ya go ! !


https://web.archive.org/web/20170507003228/http://datsunzgarage.com/


Then scroll down the page and follow the links. Look in the engine section
This capture is from 5/7/2017
If you dont see what your looking for then you can load additional captures and look again.

Good source for any old site info ! !
These sites once captured here will be there in the future.

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W.Karl Walton
Somers CT



75' - 280Z - HLS30203249 - #304 Gold Metallic (stockish)
96' - 300zx TT - JN1CZ24d3TX960293 - Black on Black (enhanced)

Karl! You Be Da Mannn!

"FUEL PUMP
If you are using carburetors you can remove the stock mechanical fuel pump from the head to reduce drag from the cam and replace it with an electric pump. There are two types of aftermarket fuel pumps: Rotary Vane, and Oscillating. The square Purolator/Facet brand electric pumps found in auto stores are the oscillating type. Reliable I'm told, but the design is very noisy with a loud tapping that's audible through the rear deck, especially if you have a quiet exhaust. A rotary vane pump produces a quieter whirring sound and is the style used on newer cars.

My own rotary-vane choice is the Carter CRT-P4070. It can produce 72 gallons per hour and 6psi max and is considered very reliable. The perfect spot for it is just under the mustache bar against the brace that holds the differential. Pushing fuel through my stock 240Z fuel rail this pump produced about 8 psi at the carbs, while the factory pressure required of SU carbs is 3.5 psi. I installed an adjustable Holley 12-804 fuel pressure regulator next to the fuel filter in the engine compartment to dial down the pressure to 5psi (3.5 for Webers). With the extra fuel demand of a L28 I think the tiny extra bit of pressure will help keep the fuel supply up without overpowering the valve needles. I have to admit it's a satisfying feeling to dial in my own fuel pressure by using an allen wrench.

2014 NOTE: this pump appears to have been replaced by the GP-4070 which Carter now calls a "competition series" pump. The specs and design appear identical to the CRT-P4070. Wonder what qualifies the GP-4070 as a competition pump?"

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1970 240Z

Also if you install another Z engine like a 280zx one, and there is no hole for a mechanical pump. Like the customers Z I'm working on now, and I will try and find the Carter pump, because that's the next thing on the list after I'm done rebuilding the carbs, and I'm ready to fire this thing up. Thanks for the info.

Personally, if you are keeping your Z stock, I see no need to go electric. I've had no issues with my mechanical pumps over the 46 years of owning my Z. I have replaced the pumps with aftermarket once many years ago, and an OEM mechanical replacement just last year. This was done just only as a precaution. None of my pumps ever failed. Maybe old school, but she still runs great!

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John Kish
1971 240Z - original owner

Mine failed twice in the first 12 years I owned it.
No big deal and fortunately I was within walking distance of a parts store both times.

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1970 240Z

Our Philly member DatsunTech72 wrote me and asked if I'd ever seen a factory-installed electric pump on a 240 car? This is our two-way:

"Hi Frank! A few years back I did a resto on a 72 Z and swapped out 2 down draft webers for the original SU set up that I built for the car.. I seem to remember this Z had what looked to be an electric fuel pump mounted near the tank that looked factory to me and had a factory wiring harness? It was a bendex style pump with a bayonet closure on one end, have you seen any other installs of this? It still had the mechanical pump running off the cam as well, but looked to be an additional pump to supply the mechanical?"

"Hi Dave ~
Yup! Good point!
The factory recommended several ways for dealers to solve their customers' complaints of the vapor-lock and percolation problems in the later-year 240s. You probably saw them when you worked as a line mech on those cars. One recommendation was to install an electric "sender" pump back at the tank, to either supplement or replace the mechanical cam pump. Some installations looked really professional and if the customer later undercoated the car it appeared to have been installed at the factory.

Pumps push better than they pull, so the mechanical pumps *sometimes* had trouble drawing fuel the long distance from the tank, especially if any of the tank's breather tubes were collapsed or clogged by insect nests. Even a small vacuum (no such thing, really, just a lower atmospheric pressure) back at the tank could defeat a pump's efforts to draw fuel up to the engine. The electric pumps served to assure fuel at least reached the front pump (if that front pump hadn't been eliminated entirely). However, the vaporlock problems occurred btwn the mechanical pump and the carbs, so a rear electric pump wasn't always the magic bullet to kill all the Gremlins. There were also individual installs of in-ine fuel filters back at the tank to trap any rust which might try to work its way forward along the fuel line. Those were made by several companies, including Bendix", but I suspect what you saw was an actual pump".

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1970 240Z

By the way Chris, I forgot to ask if your gas cap is ever hard to remove, or if you get a WHOOSH! rush of air when you open it?

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1970 240Z

My original mechanical pump is still running strong and I would only change over to reduce the drag on my cam.