I've never used one, but watched a fellow pump up a tyre that way many years ago. The same thought has occurred to me about the petrol vapour/residue.
Anyway, he seemed to use it a quite regularly and drove off happily. Mind you, he ran over a bit of flint moments later and the left front of his vehicle exploded, but it was probably just a coincidence.
I used these in the two years I spent in the Simpson sixty years ago. No, contrary to what you might think at first glance, there is no petrol vapour output by the pump. A little oil perhaps.
Operated with the engine idling, there is a pretty good vacuum in the inlet manifold - and the pump fitting that has replaced the spark plug has an inlet valve to atmospheric pressure, so the cylinder being used is filled with air coming in that way, rather than from the inlet manifold.
In my experience, the issues with these as a tyre pump are:-
1. They get hot! This may lead to singed fingers when removing them, and the rubber hose near the fitting tends to be short lived.
2. They are allowing unfiltered air into the cylinder. Not the best idea in a dusty environment.
3. If used frequently, can lead to damage to the spark plug hole thread, especially with an alloy head.
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
On a trip to the centre we found the Leyland Brothers Tree. 1968.
See their book. "Where Dead Men Lie" They were there in 66. Two Landies and a motorbike. The Series one wagon towed a heavy trailer.
Leyland Bros. Tree centre 1968 001 by Keith Cree, on Flickr

The D2 is a great vehicle, it’s retired now living life under the carport
Leyland Bros Repairs in Austral Camp.jpg
Leyland Brothers in my exploration camp in 1966. See 123Rover50's post above.
I make a brief appearance in "Where Dead Men Lie".
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
The same car, 52 years on...
IMG_1878.jpg
Edit. Err... pic taken in 2018,,
Last edited by Tins; 3rd February 2024 at 02:10 PM.
JayTee
Nullus Anxietus
Cancer is gender blind.
2000 D2 TD5 Auto: Tins
1994 D1 300TDi Manual: Dave
1980 SIII Petrol Tray: Doris
OKApotamus #74
Nanocom, D2 TD5 only.
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