Using Cylinder Compression to Air up tyres?

[postalWagon]

I was wandering around the internet today and came across a kit that used cylinder compression to air up tyres. The unit I looked at had a adapter(there was more than one for a few diferent plug sizes) that replaced a spark plug and conected to what looked like a one way valve w/ the hose and end conector. there was also a plug kit.

As I pondered what I was looking at, I remberded that exhaust jacks use the same princable. The said kit was for a motorcycle, but it got me to think I can asemble the same thing for my jeep. It would be a quick and light way to air up tyres (if it works). No it can't run air tools, I dont own any, but it would beat the added weight of a air tank or compressor.

What are your thoughts?
Cheers,

 

[bmxer06pa]

So you would have to unscrew a spark plugs from a hot engine every time you need to air up? Wouldn't you be pumping unburnt fuel into your tires?

 

[Metcalf]

I would be hesitant to pump an air and fuel mixture into the tire......

The 12V MV50 electric compressors are a GREAT low budget option. It takes a little longer, but its not THAT long, even with the big 39" tires on my Dodge.

 

[Hill Bill E.]

Not only would there be the fuel/air mix pumping in on a vehicle motor, the newer ones, with computers, may through a "Misfire Code" and go into limp mode, if run with one plug removed.

Want inexpensive air? I use a 400W inverter, and a 2 gallon 110V portable compressor. I can swap it between rigs, and use it for my finishing nailer around the house!

I had under $60 invested in both, and having the inverter was handy for other things, as is the air compressor.

 

[postalWagon]

I would plumb a fuel cut off to the carb, then it would only pump hot air.

 

[1leglance]

I remember those from when I was a kid...
didn't work well then but it was all we had until we built a York setup on one of the ranch trucks
Now as someone else said the $50ish or whatever MV50 is such a great deal nothing else is worth messing with.

 

[Idlehour]

There used to be a neat kit on the market that took a vw motor and set it up so I ran on 2 cylinders and used the other 2 as an air compressor.

You can pick the spark plug air adapter you are talking about for a Couple of bucks at the auto parts store. They are used to pressurize the cylinder to hold the valves in place while you replace the valve guide seals. Seems like it would be pretty inconvenient to pull a spark plug, but might be handy to carry if you got into trouble. Not sure how to keep the fuel out on a carbed motor. You could probably just pull an injector on an newer motor.

I think an old ac compressor would be they way to go (safer/less burney) for on board air if you were going to use it often.

 

[cruiseroutfit]

There is a thread here on ExPo with a bit more info about the said 'Spark Plug compressor', I had one that I tinkered with for a bit, not sure if its still around or not?

They are quite different however from an exhaust jack which is using pure exhaust (non-flammable, no engine parts removed) and the spark plug contraption uses your engines cylinder compression. Modern vehicles could unplug the fuel injector to that cylinder, then again most modern vehicles have spark plugs that are a pain to remove

Edit, found the thread: http://www.expeditionportal.com/forum/threads/23267-Spark-plug-replacement-air-compressor

 

[SilverBullet]

MV50 option here too, 4 tires, 15psi-35psi in my 35's and it was done in 20 minutes.

Air/fuel or hot air into a tire sounds like a bad idea to me.

 

[Binder Lou]

It does work.

My dad had one under the seat of our '55 GMC Suburban. It was called a Chuffer and was quite simple. There is a check valve in the unit so that when the cylinder goes to a down stroke the check valve opens and the unit draws air from outside the engine. Internal vacuum, the engine is at idle, keeps the cylinder from drawing from the intake system. It makes a great sound when it runs and it will pump up a tire. I won't speak to what a computer might do with that circumstance, I drive an IH.

 

[postalWagon]

so I broke down and ordered the valve unit. the next trick will be to fab a short adapter and get a longer hose.
the adapter will be the part that gets put in and taken out it will be knurled.
my 1975 jeep has no computer to fight with.

 

[Wyowanderer]

So you would have to unscrew a spark plugs from a hot engine every time you need to air up? Wouldn't you be pumping unburnt fuel into your tires?

Yes. If you use a sparkplug socket with a magnetic insert, it isn't an issue. The fuel in the air isn't either; mine draws outside air into the cylinder and pumps it out into the hose/tire.

Using the device on a vehicle with fuel injection would require disconnecting the injector where possible. I've used mine for years and never had a problem.

 

[bmxer06pa]

This just seems like a complicated solution to an easy question.

 

[Wyowanderer]

This just seems like a complicated solution to an easy question.

Funny that you put it that way. I use mine precisely because it's lighter, easy, and for my money, better.
Naturally, YMMV.

 

[postalWagon]

^2, and it fits in my ONE bag for tools.