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I agree that would make changing the oil filter much easier, but wouldn't all the oil left in the filter leak out all over everything below it when you take it off?

I might be the minority, but I like the oil filter to be lower on the vehicle, with nothing for the oil to drip down on to when changing it. You are already going to be down under there to take the drain plug out...

Back from the hardware store; got a hex wrench that fits the reed valves.

First I took off the intake valve on the cylinder that wasn't working. Apart from being a little dirty, the valve itself and the spring looked in decent condition. It had a little mound of what I think was paint on the exposed part of the valve, but all of the other valves had some paint there as well, so I just scraped it off and reinstalled it.

Before I had taken the valve out, I tested the whole motor/pump/micro-reservoir assembly:


As you can see, pressure wouldn't build above about 15 psi. The intake reed valve was letting air out. After I took it out, cleaned it, and re-installed it the pressure held up to about 45 psi (that is as high as I want to take this thing until I've done a more thorough inspection of the internals of the pump.

Next I took the exhaust reed valve off:



(In the words of Jamie Hyneman and Adam Savage) Well there's your problem! There's no "real" valve there, just what someone put in there, hoping it would work. It almost looks like a piece of gasket material (how ironic). Without that valve there, the pump will still work, but it will be down a cylinder and will leak (more than it would) air out of the intake reed valve.

I tested that by holding my finger over the air outlet on the reservoir, getting the pressure up to about 45 and shutting the motor off. The pressure dropped rather quickly. If I put a finger over the air outlet AND the bad cylinder's intake valve, the pressure drops slower, but still drops.

I MIGHT be able to make something that can be used as a reed valve out of a small piece of sheet metal, since that is what all the other valves are; springs and a piece of metal.

Even if I get that cylinder working again, I'll probably need a check valve between the air outlet on the micro-reservoir and whatever tank I use.

EDIT:

Oh, and I also took a video demonstrating the crank wobble:

I was thinking about doing something like that, but it is down on my list. I'm trying to get away from the mentality of, "fix something broken by breaking it the opposite way." Plus, I don't have a sledge hammer. If I really wanted to I could put the pulley back on, mount the pulley firmly to some surface and then grab the pump block and try and unbend the crank. I have a feeling that if I went the sledge hammer route the pump casing might crack from the impact.

I just bought a very old sears/craftsman air compressor from my local flea market for $15. I've been wanting some form of compressed air for general in-the-garage DIY type stuff for a while now and I thought that $15 isn't too much to lose if it doesn't work.





It was worse before I took these pictures, the entire base and some of the pump and reservoir had 1/16" to1/8" of oily-dusty... stuff on it.

I removed all of the pieces from the base board and cleaned them as best I could. While the pump was off of the base, I noticed that the crankshaft was slightly bent; when the pulley was installed on it, it would wobble about 1/4 inch off-center. Then I noticed that on the seals on both ends of the crank shaft were leaking oil. That explains the mess all over the base board.

Now to get to the point of this thread. I want to partially disassemble the pump and make new gaskets around the crank seals (they are bushings, actually) and inspect the top end of the pump; there are 4 cylinders, but only 3 are working.

Since this pump is nearly an antique, original gaskets are impossible to get. I need to know what, if anything, I can use to make a new head gasket. I first thought of form-a-gasket, went to their website and found this. Under applications it lists compressors and diesel head gaskets. It seems like it might work.

Does anybody else have any other ideas on what I could use? Preferably something that is available at a hardware store or some place like tractor supply co.

I should also mention that I will be running up to about 100 psi and it will only be used for about 30 minutes every... month or less, so very light duty.

By "won't start" do you mean the engine will crank and turn over but not start or will the starter just not turn the engine at all?

About an hour ago I saw someone riding down the street on a bicycle fitted with a bolt-on 49cc two stroke engine towing one of those small covered trailers you put small children/infants in. I wasn't close enough to see if they had a child in there or not but I REALLY hope they didn't.

I could understand using one of those to carry cargo or groceries but never a child when it is attached to something with an engine.