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TR2/3/3A Fuel pump inertia switch vs. dead engine switch?

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GTP1960

GTP1960

Jedi Knight
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I've replaced my mechanical FP with a facet electric model.
I have a revolution electrical dead engine automatic cut-off switch, that I will be installing, but after reading several threads on inertia switches I'm wondering if I need that, also? ( or instead of)

If you have a preferred brand I'd like to know that too.
(BTW: Also a prefer brand of inline fuel on/off valve appreciated)
dont want to scrimp on something like this.

reminds me of a sign posted at my little local flying club AP, years ago;
"factory second parachutes sold here! Great prices!"
Thanks
 
The inertia switch in my TR8 was a royal PITA. Unavoidable pot holes and other road anomalies would trigger it. Killing the fuel supply in traffic on the interstate was annoying and very dangerous at times. Perhaps mine was over sensitive but none the less, with all the bouncing around a TR3 can go through, it might be a problem.
 
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Kind of belt vs suspenders, IMO. Triumph leaned towards inertia switches, and the ones on my Stags have never given me any trouble (although it's possible they don't even work). Other car makers (like VW) seem to prefer engine cutoffs. Modern cars typically do both (through the ECU).

I'm not convinced it makes all that much difference on a TR3 anyway. With the tank up so high and an open vent, gravity will most likely empty the tank even if the fuel pump doesn't.
 
Any serious accident in one of these is going to be a physical as well as financial disaster. You've got to drive one like you would ride a motorcycle. 110% defensive.
 
Guy, what pressure does your Facet electric fuel pump work at? Are you planning to also install a fuel pressure regulator? The other day in one of my manuals I read a statement on the fuel pressure requirements for the 4 cylinder Triumph but today I cannot find the statement. Does anyone know what fuel pressure Triumph specified? I'll report back if I find the statement in one of my Triumph manuals. Thanks!
Regards,
Bob
 
The spec for the original fuel pump used on TR2-4A was 1.5 to 2.5 psi (or in other words, 2 psi +/- 0.5 psi)
 
TuffTR250 said:
Guy, Are you planning to also install a fuel pressure regulator?

Hey Bob,
missed your question about the pressure regulator.

Moss does not recommend it with the facet pump. In fact the moss video implies if you need a pressure regulator, then you have the wrong pump.

best regards

Guy
Click to expand...
 
Thanks Randall for the pressure spec!
Thanks Guy, I did not know that about electric fuel pumps. What model or part number Facet fuel pump did you get to ensure it has the right pressure?
Regards,
Bob
 
Facet makes several different pumps, each available in a wide range of pressure ratings. I don't know, but I would guess that Moss is supplying P/N 40104. If you wanted to stick closer to the original pressure, there is P/N 40163 rated at 1.5 - 2.5 psi (but only 17 gph, which should be plenty for a stock engine). There is a chart at
https://www.aircraftspruce.com/catalog/eppages/facetpumps.php

There has been some debate in the past over use of pressure regulators. Some claim it causes problems, others say it works for them. A lot of racers fall in the second category, so I'm inclined to believe it can be made to work well. One important point is that the pressure regulator requires a pressure drop across the regulator, so you definitely need a higher pressure pump if you are going to run a regulator.

Something else to consider: The little rectangular Facet pump makes a fair amount of noise, which can get greatly amplified if you bolt it directly to sheet metal. Good idea to mount it with rubber isolation. I actually did a double isolation mount on the Stag, which combined with being in the trunk, makes it inaudible when the engine is running.

That $10 filter shown by Moss is a standard Ford part, readily available at FLAPS for less than half the price. It does need to be replaced from time to time.
https://www.oreillyauto.com/site/c/detail/WIX0/33046.oap?pt=02515&ppt=C0023
 
Thanks for that information Randall. A couple of questions: I got a used Facet pump but it has no p/n label on it. How do I tell which one it is? Also, I was considering mounting it in the same place as the old mechanical fuel pump using the same bolts that hold on the blanking plate. The problem is that the metal filter like the Ford one you noted points down and interferes with the crankcase breather pipe. Can I just put a hose barb elbow in place of the filter and use a separate inline fuel filter? Or is there some function that the metal filter provides?
Regards,
Bob
p.s. sorry for hijacking this thread.
 
Look carefully, normally the part number is stamped into the metal wrapping. If it's not there, I think you've probably got one of the 'clone' pumps. Only way I know to test it is to hook up a pressure gauge (and 12v and something for it to pump). Most vacuum test gauges will also read fuel pump pressure. (for carburetor type pumps, not fuel injection)
https://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

I don't know of any reason you can't put the filter remotely. The pump seems very tolerant of crud in the fuel, so I don't actually have a filter at the pump at all, just the stock in-line near the carbs. However, note that Facet recommends that the pump be mounted near the fuel tank.
https://www.facet-purolator.com/faq.php
 
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