TR6 Conversion to electric fuel pump

[AndreL]

The traffic is so bad, heat shield, insulated fuel pipes could not prevent fuel vaporization and/or percolation, on a cool day.
The frequency of occurrences makes the car impractical in the city.
Raise the bonnet, wait 20-40min depending on temperature, and it runs like a champ again.

I must convert '69 carburetor model I've had for 50yrs, with electric pump, relay, regulator, return pipe, vapor canister... & keep Stromberg 175 CD-2.

Could someone direct me to articles on the subject.
All advice welcomed.
Thank you Basil & all!
Andre

 

[mctriumph]

I suspect you have other problems. Vapor locking is NOT cured by electric fuel pumps.
Mad dog

 

[Rick_Thompson]

I suspect what you are asking for is recommendations for an electric pump, as you are still running the stock mechanical pump?

If so, the best one I could find is a Purolator Facet Gold. I blanked off the old pump with a plate and gasket and mounted the new electric Facet down in the engine compartment on a side frame rail. It pulls fuel nicely and I can keep a cheap 12V pump with alligator clips in my spares bag in case I have a failure. Couple of ty wraps and move the fuel lines, clip on the battery and good to go.

 

[JHaydon]

"Cure" may be a strong word, but an electric pump will eliminate one major cause of vapor lock, which is low pressure in the fuel line. (Lower pressure = lower boiling point; higher pressure = higher boiling point; mechanical fuel pump pulling from the front = lower pressure; electric fuel pump pushing from the back = higher pressure)

If you chose the correct fuel pump there will be no need for anything else. Facet brand fuel pumps draw less than 2 Amps so they do not need a relay, just a 3 Amp fuse. Low-pressure pumps are available that do not require a regulator. No reason for a return line or vapor cannister unless you are shoehorning in a 60psi pump for fuel injection! Some pumps also allow free flow when they are turned off, which means you can wire the pump to a switch and run it only when you're stuck in summer traffic. When you're on open roads, you can turn it off. Also useful if the car has been sitting for a couple of weeks and the carb is dry.

The one drawback to Facet pumps is that they are loud, like hear-it-over-the-sport-exhaust loud. Personally I find it comforting to hear, knowing that the pump is running; but lots of my customers complain about it.

Facet recommends 2 models for carbureted imports, either the vintage-looking 477060 "Black Top" or the more compact 40104. Either one will work without a regulator and can be used as an on-demand pump.

Can you tell that I work for a Facet retailer?

You can find either model at various places online, but be sure that you are getting GENUINE Facet, made in the USA since the 1950s. Facet pumps are so popular that there are several knock-offs out there which Do Not Work.

Edit: Rick's pump is likely the 477060 -- Facet makes a lot of different models in their Gold-Flo line which all look identical to that one. Purolator, Facet, and Bendix are all different brand names for the same pump, invented by Bendix in the 1950s; mergers and spinoffs changed the company name to Facet in 1976, but they used Purolator as the brand name in retail markets.

 

[Rick_Thompson]

And yes, I did not use any relays. Attached at the fuse block on terminal that is hot when key turned on, and I also used an inline fuse.

 

[Sarastro]

I have installed electric pumps and pressure regulators in my TR4A and Porsche 912. I run the pump at elevated output pressure, 5-7 PSI, and use a regulator to reduce it to 2-2.5 PSI at the carbs. This has two advantages: first, it keeps the pressure at the carbs where I want it, as the pressure ratings of the lower-pressure pumps is pretty wide; and second, I like to think that the elevated pressure reduces the tendency of the fuel to bubble and thus to vapor lock, but I have no empirical evidence that it helps in that regard. My main concern was that previous mechanical pumps had excessive output pressure and sometimes caused flooding; now, I can set the pressure at the pump precisely where it belongs.

Engine Externals

> Porsche 912 Fuel System Upgrades < (scroll down a bit)

It's hard to say how much effect this has on vapor locking. It's likely that moving the pump outside the hot engine compartment has more effect than anything else.

 

[JHaydon]

I run the pump at elevated output pressure, 5-7 PSI, and use a regulator to reduce it to 2-2.5 PSI at the carbs. This has two advantages: first, it keeps the pressure at the carbs where I want it, as the pressure ratings of the lower-pressure pumps is pretty wide; and second, I like to think that the elevated pressure reduces the tendency of the fuel to bubble and thus to vapor lock,

Both excellent points. For racing, the general rule of thumb when choosing an electric pump is to get one with a pressure rating twice as high as what the carbs want, then use a regulator. That ensures that the carbs will "always" get that pressure, regardless of demand. For most street use, you can generally get away with a lower-pressure pump. It depends on the engine and the type of driving you expect to do.

And yes, there is a scientific reason behind raising the pressure in the line. It's the pressure cooker concept, the same reason we use pressurized radiator caps. Pressurizing a fluid will raise its effective boiling point, i.e., keep it liquid even if the temperature reaches its normal boiling point. And on the flip side, pulling a (partial) vacuum on a fluid will lower its boiling point. (Apparently if you get sucked out of the air lock in space, you won't have time to suffocate because your blood will boil first?)

Back to the idea of regulating down a higher-pressure pump: Pumps are generally rated to a maximum output pressure and a maximum flow rate. The thing is that you can't have both at once. As flow (engine demand) increases, the pressure will drop. Taking the 40104 as an example, it's rated to 4 psi max pressure and 28 GPH. If the engine wants to consume 20-ish GPH at full throttle, the pump will be pushing it with less than 1 psi. But the 40106 model (7 psi max, 32 GPH) should still be chugging away at something closer to 2 or 2.5 psi. Note that this much fuel demand would only happen at full-throttle operation, which is where race engines live most of their lives. Street driving should rarely, if ever, come close to that -- and even then, just for very brief periods (e.g., "oh h*ck this truck is coming right into my lane!!") (Almost-related, VW drag racers knew that they could complete a 1/4 mile pass with a mildly built engine just on the fuel in the carb float bowl!)

 

[AndreL]

Informative & interesting webpages from Sarastro,
I like the simplicity of the Facet 477060 set up & on-demand, free flow feature,
graciously explained by JHaydon & Rick. Thank you!

If I knew where you work JHaydon, I'd order from your shop.
Pegasus Auto Racing in nearby WI has good reviews, also warns of knock-offs,
sells them for $122. plus mounting kit, fittings & switch, good deal!
The spec sheets corroborate your information.

There is really nothing wrong with the car.
The real cause, city of Toronto is implementing woke ideology goals like elimination of cars
by creating lane restrictions & traffic impediment measures everywhere. It's continuous traffic gridlock!

I'll try the Facet 477060, mounted on the frame below the tank,
as a next logical step, to see if the increase pressure gets me through congested traffic. Thanks!

 

[JHaydon]

Pegasus is an excellent place to buy from (and also a great place to work ). We deal directly with Facet and keep pretty big numbers of each model in stock and ready to ship.

We have many customers in Canada and ship multiple packages to Canada every day. Recently DHL has been the quickest and most economical shipping method to Canada, while USPS (mail) to Canada has been the worst.

 

[AndreL]

I'm not ignoring doubters & dissenters.
' will try this for 8 month season & re evaluate next winter.

USPS-Canada Post should not be in the parcel business,
UPS adds fees & no one really knows the fee structure across the border, 'cause it keeps changing.
I'll try DHL.
Thanks JHaydon

 

[RJS]

One other thing to note, heat and gasoline can combine to create one of two problems (both related to the Reid Vapor Pressure (RVP) of the gasoline).

1. Vaporization (aka vapor lock): this occurs in the fuel line and results in a lean mixture as the fuel pump cannot push vapor - and the engine starves for fuel. Modern cars avoid this with high pressure fuel lines to fuel injectors. Modern cars also have a return line to the gas tank which keeps the fuel continuously circulating though the lines before it has a chance to absorb too much heat.
2. Percolation: this is when the fuel boils in the carb body, float bowls, etc and results in an overly rich mixture. This is usually accompanied by a heavy gas smell under the hood. Again, modern cars have high pressure fuel injectors so no oppty for the fuel to boil anywhere in the system.

The higher the RVP, the more likely it will vaporize/percolate. RVP of gasoline is higher today than it was in the 1960-70's Ethanol in today's gas raises RVP as well. Also, the EPA mandates higher RVP in the winter to assist cold starting - normally sold Sept 1st to May 1st. So, if you are burning a tank of winter blend fuel on a particularly warm spring day, guess what?

Bob

 

[poolboy]

Good to see someone else (Bob) make the distinction between vapor lock and percolation.

 

[JHaydon]

The higher the RVP, the more likely it will vaporize/percolate. RVP of gasoline is higher today than it was in the 1960-70's Ethanol in today's gas raises RVP as well. Also, the EPA mandates higher RVP in the winter to assist cold starting - normally sold Sept 1st to May 1st.

That's where I always get confused when we're talking about pressurizing a fluid to raise its boiling point (the main reason I didn't mention vapor pressure) -- lower boiling point equals higher vapor pressure... right? Basically?

Is it wrong to think of vapor pressure as a pressure in the fluid trying to make it become vapor? And increasing the pressure in the fluid vessel (external pressure acting against the fluid) resists / pushes back against the vapor pressure?

Can you tell that junior year physics is when I started to realize I wasn't as smart as I thought I was?

 

[Mikie808]

Interesting- I just took out my electric fuel pump in favor of a new mechanical one with a prime lever (I would imagine that’s the factory set-up). It seems you shouldn’t need the extra pressure and that the problem is somewhere else. I got tired of the rattling sound and kinda like the old tech.

 

[RJS]

JHaydon,

You got it right. The higher the vapor pressure the more likely/easily a liquid will want to convert to a gas in same conditions.

Bob