Impact switch

[Hamish]

I fitted a huco pump and an inertia switch to my 3a after mechanical pump suffered diaphragm failures. I wish I had put the switch in reach - but in saying that it hasn’t tripped yet and I do throw it about a bit and run the rumble strips in sprints etc.

[JohnD]

I've tripped mine, Hamish, by running the kerbs.   It's going to ruin your run, but if within reach, you can avoid being towed away!

Relatively easy to relocate to the dash?

[Nick Jones]

14 hours ago, PaulAA said:

But it does do the fuel vaporisation malarkey in hot weather. Howerever, I'd assumed that this was the result of under-pressurisation, rather than too much.

It’s a combination of things. Modern fuel vapour pressure is higher than back then so boils more easily. Anything that heats the fuel is a problem and the metal pump body, bolted to the hot metal block is one such built in feature, along with the block-hugging pump to carbs pipe work.  The pump is a particular problem as the turbulence in it, especially the valves, further promotes boiling and the pump is much less effective at pumping vapour, which also displaces the fuel itself.

An electric pump, mounted away from the heat of the engine, and pipes run away (as far as is possible) from the block helps take that out of the equation and means that at least the fuel does arrive at the carbs in sufficient volume and cooler.

Seems to work on the GT6 though I don’t consider it fully tested yet.

[Escadrille Ecosse]

2 hours ago, JohnD said:

I've tripped mine, Hamish, by running the kerbs.   It's going to ruin your run, but if within reach, you can avoid being towed away!

Relatively easy to relocate to the dash?

This was always my concern which was why I put it inside the car within reach. It's mounted on the A post which I thought should be about as solid as I could get.

I've contacted the tyre wall a couple of times . One time tripped the switch the other didn't

Mine is the Triumph PI type, new-old stock that must have been one of the last ones available from Rimmers. It does work when manually impact tested.

Still looks brand new and I haven't had any issues with it although given the comments above on reliability of these switches something to keep an eye on.

[MilesA]

3 hours ago, JohnD said:

I've tripped mine, Hamish, by running the kerbs.   It's going to ruin your run, but if within reach, you can avoid being towed away!

Relatively easy to relocate to the dash?

Positioned mine under the 3A dash on the right, mounted vertically on the back of the brake / clutch master cylinder box. Very easy access.

Miles

[Hamish]

that's another job on the list then !! 

my old car to do list never gets any shorter !!