Interesting air starter layout

[veggie]

Here's a nice air starter setup.
Simple to actuate, just open the ball valve.
Can someone explain how the air is released from the cylinder once the ball valve is closed.

veggie

[BruceM]

The ball valve isn't- it's a three way air valve.
Or there's an air bleed valve/hole on the pressure side.

The retracting actuator is an original arrangement. Most of us tilt the starter upward with an air actuator. (5/8")
It looks way to large in diameter- excessive force on the starter motor outboard bearing, unless it has a separate air pressure regulator or a hard stop.

[veggie]

I noticed he has a regulator between the valve and the cylinder, so the force may be manageable if the regulator is set to a low enough pressure.

veggie

[BruceM]

Thanks Veggie, you were posting as I was editing.  The smallest regulators will work fine for cylinder air regulation.  Air cylinders are very cheap, though, so I say just use a smaller cylinder.

One other comment-  the Gast 4AM or 2AM need a lot of air- a 1/2" supply without any 1/4" automotive type connectors will result in much more power.  On the exhaust side, a short 1/2" line to a garden tractor muffler works best.  I like the Goodyear yellow 1/2" flex hose best, it's often on sale on ebay.

[veggie]

I'm just rigging the air system for my air starter.
If you had a choice, would you go with a 3 way valve? or a small bleed hole on the high pressure side of the cylinder.?
Seems like the bleed hole would be the simplest. Not much air being lost.

veggie

[BruceM]

I haven't tried the bleed hole method, don't know if it will work well.  The issue is will it reduce the pressure fast enough- which may not be that critical.  Please report if you try it.

Please note the addition to my above post about supply and exhaust air supply issues.

[BruceM]

Thanks Jens, I forgot the air motor would act as a very fast acting bleed! 
Not so sharp today...

[lowspeedlife]

It appears the air cylinder is pulling the air motor into the flywheel on a sliding mount, slick set up. BTW isn't this the guy that had the video of little boy leaning over the running engine ?

  Scott R.

[mobile_bob]

you might look into a truck QR1 valve
it works like this

you put air into the valve an it closes the exhaust port and delivers the air to the delivery port
when you cut off the air to the in port the QR1 releases the air to the delivery port and exhausts it through
the exhaust port

they come in 3/8 female pipe and also the larger 1/2" female ports, also very common and cheap
they come in plastic or aluminum as well.

they are relatively small fitting in the palm of an average guys hand.

bob g

[veggie]

The valve there is a regular ball valve. When he opens it, pressure is applied to the air motor as well as the cylinder through the regulator so force is adjustable. When he closes the valve, the air supply is cut off from both the cylinder as well as the air motor but the connection between cylinder and air motor never changes. Any pressure that is in the air cylinder vents back through the regulator and then through the air motor.

Thanks for pointing that out Jens.
I like the simplicity of that system. A setup I would like to emulate.

veggie

[veggie]

By the way Jens, how do you like the sound of the air motor 

veggie

[BruceM]

Veggie,  sorry I missed the obvious.  One thing to think about is good human factors- put the valve somewhere easy to operate while you are busy with the decompression valve, preferably not bending over like the one shown! As long as the supply is 1/2" hose, some extra length is fine.  Occasionally Harbor Freight carries an air foot valve that would keep your hands free, also.