Outer Limits 4x4 Board

Posted: **Sat Jan 17, 2004 1:07 pm**

my dear old grandma gave me an old (not used) "engine air pump with gauge" that ya can use to pump up ya tyres and stuff...

the idea is that ya unscrew one of the sparkplugs and screw the pump thing in... run the engine off three cylinders (in my case), fresh air enters the pump cylinder thing that's plugged into the spark hole and gets pumped to the tyre or whatever. apparently vacuum in the inlet manifold prevents fumes or anything else from the engine from going thru the pump.

my old man says these things were real popular a decade or two ago... just wondering if anyone's used em? are there any issues with using a device like this to pump my tyres, or is it gonna be all good?

cheers...

Posted: **Sat Jan 17, 2004 2:08 pm**

Got one here !!!. they work well and were cheap as chips too.

Worst thing about em is ....."Try screwin a hot sparkplug out and then screwin the pump in to a hot motor" !!!

ouch, GRRRR bugger OUCH.... even worse with extractors !!! :bad-words:

Posted: **Sat Jan 17, 2004 4:01 pm**

lol... that's gotta hurt. sounds like a job for a passenger :twisted:

Posted: **Sat Jan 17, 2004 4:26 pm**

Not a good idea with fuel injection....................

Posted: **Sat Jan 17, 2004 4:33 pm**

A friend of a friend used a big old V8 as an air compressor... it ran on one bank of four, and the other bank of four pumped out more compressed air than anyone could possibly need through the exhaust manifold.

Of course he only had fuel going into the power side of the motor. With this spark plug idea though... I am struggling to see how you keep fuel out of the cylinder in question. Can anyone explain this?

Jason

Posted: **Sat Jan 17, 2004 8:16 pm**

the cylinder is not connected to the air going out, there is something in there which gets pushed in and out by the cylinder pressure which in turn pumps fresh air out the air line.

Posted: **Sat Jan 17, 2004 9:00 pm**

never heard of such a thing but it sounds cool...

how well do they work ??

Posted: **Sat Jan 17, 2004 9:17 pm**

big red wrote:the cylinder is not connected to the air going out, there is something in there which gets pushed in and out by the cylinder pressure which in turn pumps fresh air out the air line.

As I said, not a good idea with fuel injection as the fuel is delivered at pressure over the valves and will enter the cylinder regardless of any significant airflow through the inlet manifold. You will also have problem codes aplenty coming from your ECU if you disconnect a plug +/- injector.

The concept works fine with carbies as they rely on venturi effect (restriction) and will take the air from the integrated valve in the plug replacement as it comes from a less restricted source (free air).

Posted: **Sun Jan 18, 2004 2:24 pm**

fuel injection? ECU? don't think my zook has heard of them....

Posted: **Sun Jan 18, 2004 4:19 pm**

You know, if you had the balls you could drill a hole in your head (I mean the one on your car, not your own... although... hmmm...) and thread it so that one of these was permanently fitted. Or not exactly one of these, but something like it, that could be activated or deactivated, and fully seal when deactivated.

This would make a really effective air compressor.

Hmm!

On the other hand, if as suggested in the post above it doesn't actually use the air inside the cylinder itself, but rather is just powered by cylinder compression, why couldn't you run it off the exhaust instead? You know those holes you plugged up when you threw away all the antipollution crap that pumps air into the exhaust? Just thread the thing into one of those and voila...

Jason

Posted: **Sun Jan 18, 2004 8:28 pm**

V8Patrol wrote:ouch, GRRRR bugger OUCH.... even worse with extractors !!!

i feel your pain

damn extractors being so close to the spark plugs

Posted: **Sun Jan 18, 2004 10:17 pm**

chimpboy wrote:A friend of a friend used a big old V8 as an air compressor... it ran on one bank of four, and the other bank of four pumped out more compressed air than anyone could possibly need through the exhaust manifold.

Of course he only had fuel going into the power side of the motor. With this spark plug idea though... I am struggling to see how you keep fuel out of the cylinder in question. Can anyone explain this?

Jason

I have seen a pair of VW motors mounted on a trailer back to back used for this purpose, one being the compressor and the other the motor.

Posted: **Mon Jan 19, 2004 9:56 am**

The old man drilled the head on the old "FJ Holden " he had years ago then fitted an clutch ( the bit on the end of an airhose ), worked a treat and seldom burnt himself.... mind you that was 30 years ago !!!

Bloody simple and very effective

Posted: **Mon Jan 19, 2004 5:49 pm**

Interesting tech subject !

No good for my diesel though.