Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I have an antique air compressor.
I spent more money rebuilding this thing than if I had just gone and bought a cheapo air compressor.
A small part of the reason for that is just being obsessive about getting something done. Meeting a challenge. Not being "beaten" by a simple machine.
Doing something that most people wouldn't even attempt. (Some because they they couldn't. Some because they just aren't interested. Some because they consider it a waste to do something like this when they can toss it and buy a cheapo to replace it.)
Part of my reason for doing all I did is because the compressor IS an antique. Built before 1930. Is that cool, or what ?
Part is because I just don't like the cheapo, chintzy, plastic and bubble gum quality of all the crap that I could afford. I like that this is a bullet-proof, belt driven, oil lubricated, double piston, antique like my grampa would have used.
~~~
I am going to start this thread with a "customization" that I have done to every compressor I have had for decades.
I detest those cheapo "ballcocks" that they put on compressors to drain the air at the end of the day. (And any water that has condensed in the tank during the runtime.)
The first thing I do with any compressor is remove that ballcock. Then I use 1/4" pipe and fittings to plumb the drain opening out from under the tank to a place that is more easily accessible.
Then I put a ball valve on the end of that.
I install the ball valve so that the handle is flipped up when the comressor is turned on, and flipped down when the compressor is turned off. Just like a wall switch. Easy to remember, and easy to see at a glance.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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That first pic is of the valve with the handle flipped up, the compressor is turned on.
The next pic is of the handle flipped down, after I turned the compressor off. Notice how it is all frosted up. It was holding 20 gallons of air at 130 pounds of pressure, with no leaks.
One good reason for doing this is that it makes it easy to empty the tank at the end of the day. Most tanks do not get emptied at the end of the day because it is so difficult to reach up under the tank and open that funky ballcock.
Now all you have to do is to flip that handle down at the end of the day, and flip it back up the next time you run the compressor.
Another good reason to make this so simple is that if your compressor is hard to start when it is cold, you can leave that ball valve open when you first start the compressor up. The compressor doesn't have to work against pressure, and will start a little easier.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I'll be back later with pics of the motor, the head, and the extra tank that I worked on.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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The motor for this compressor was made by Wagner Electric Corporation. Back when they still made motors. Like I said, before 1930.
Here is a pic of the motor just minutes after I brought it in the house to dry out.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Here is the information on the plate...
wagner electric corporation
354
st louis usa
Alternating current motor type KA
frame 75
model W30 B185 k354
3/4 hp
1725 rpm
1 ph 60 cycles
110v 10.4 amps
220v 5.2 amps
cont rating 40c ser number n81
The next pic is of the wires, inside the motor housing.
These wires are cloth covered. But in surprisingly good shape.
They were soldered together to pigtails external of the housing, so I left everything as it was, and used the pigtails to wire to.
For a bit of extra bulletproofing, I tightened the plastic "nut" that held the wires snug in the opening through the housing. Then I formed epoxy putty around all that on the outside. The point was to make the wires as immobile as possible, to minimize chances of cracking the insulation.
Once the putty was cured, I wired everything up, then used a plethera of nylon wire ties, to tie everything down as firmly as possible at the housing.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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This motor turned out to be quite unusual by today's standards.
It is what is called a repulsion-start motor. (Thanks to Bill Hartmann at Breaktime for that information.)
Basically there is a centrifical switch in the front of the motor. (The end where the pulley is mounted.)
On the other end is what is unusual. It is a carrier with 4 brushes. Those brushes ride on the end of the commutator when the motor is starting up. Shorting power directly to the commutator.
When the motor reaches about 75% of it's operating speed, the centrifical switch on the other end pushes a rod through the commutator, and thereby pushes the brushes away from the commutator.
Modern motors use a capacitor to start up. This one uses these brushes. This motor has approximately 400% torque when those brushes are engaged. Wow !
This pic is the centrifical switch.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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This last pic of the motor shows the brush assembly.
This compressor was run in an auto body shop. This motor and the compressor head were both clogged with a combination of grease, bondo dust, sanding dust, and paint spray residue and powder/dust.
Cleaning that out of the parts, cleaning the parts, oiling, greasing, and reassembling them is pretty much what was needed.
This motor started and ran like a charm after I broke the parts inside loose from that cement like substance.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I'll be back again later.
Next up, the compressor head.
Then The extra tank. And then a discovery I made about one-way valves...
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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On, to the pump head...
This is a pic of the entire head.
This is after I had rebuilt the top end, put it back together, and put it back on the compressor setup.
The diamond shaped thing pretty much in the center of the pic is where the air enters the pump. The air goes straight into the "crankcase", and is moved up through the pistons, through the valve in the top plate, and on into the tank.
The plug you see below that reveals the end of the crankshaft. Nothing more. The pulley is on the opposite end. You cannot fill it with oil from there because the shaft is taking up the entire bore.
As it is now, I have to put oil in through the air inlet.
I have no idea how much oil is supposed to be in here. I assumed it was like any other assembly that I have seen, and the oil has to come up just high enough for the crankshaft to just about get wet. This will dip the piston bearings in and out of the oil, and throw oil everywhere else that it is needed.
However, when I filled it up that much... The compressor almost literally will not turn over. Even that tough old motor will not turn it.
I had to pretty much drain almost all the oil out of it before the compressor would run halfway reliably again.
My thoughts at this point are to take this head completely apart... Clean every part well. Enlarge the air intake. Drill and tap for a fill plug in the top "bowl". Use assembly lube when I put it back together...
Then with the compressor running, very slowly add what I have decided to run as air tool oil... Generic, cheap mineral oil, with some antifreeze added.
If the compressor starts to bog down again, I will turn it off and wait a while for all the oil to drain to the bottom of the crankcase then try it again. If it still bogs, I'll know to drain some of the new oil back out again.
I did not take the main body apart on this thing. I am concerned that the pistons will be pulled out of their bores, and I have no idea how I would go about getting them back in there.
If the very bottom of this cast assembly had a removeable plate, I wouldn't worry so much about it. But it is cast like two bowls. Top and bottom. Which are then bolted together like a clamshell. If I pull them apart, the pistons will stay with the bottom half. That will pull them out of the bores, and I have no idea how they were fished into those in the first place.
I may at some time, just go ahead and take my chances. I'd like to get all the rest of the crap cleaned out of this crankcase. Check the bearings. And make the other changes.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Next pic is the very top of the head.
Where the brass fitting is, is where this head was plumbed from before. The threaded hole in the rounded diamond shaped area had a pipe plug stuck in it.
Along the way, I removed the pipe plug, stuck my fingers over the holes and spun the compressor many times. In the end I was convinced there was little to no bleedover from one piston to the other, through the valve body in the middle plate.
So, in other words, the people who had this before were wasting close to half the potential of this head.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Next up is the two top plates.
In this pic you see the underside of the very top plate, on the right.
Those two holes are the holes you saw on the top of the head. You can see the brass fitting in the other side of the hole on the far right. I am thinking I may drill out the smaller of the two holes, (where the pipe plug was), and tap it for a larger fitting.
The plate on the left is the top of the valve plate.
That also has a hole through right on top of each piston.
There is basically a "reed" valve on top of each piston hole. As the piston forces the air up through the reed valve, the flat springy part is forced up, and the air passes.
When the piston drops, the flat spring falls back over the hole and seals it. So the piston bore now has to fill through the body of the piston. More on that fill, later...
The rectangular metal on top of the valve just keeps those reeds from popping up too far.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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The next pic is the bottom of the valve plate.
This surface is what is right at the top of the piston bore.
The air is forced up through those holes, and through the reed valve above. The valve you saw in the previous pic is what is on the other side of this plate.
You can see that the orifice on the right has been pretty close to completely clogged with the same buildup that was in the motor. Grease, sanding dust, bondo dust, paint overspray, etc...
The one on the right is the one that was plumbed. The one on the left is the one that had a plug in the top of the head. (I poured some oil down that hole immediately when I removed the plug. That's why there is oil all over everything.)
Those gaskets seem to be made out of lead.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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The next pic is of the top of the piston portion of the head.
The pic is a composite of before and after cleaning.
Those slots in the top of the pistons are the beginning of a clue as to how the air pump operates.
More on that with the next pic.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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In this pic you can see the workings of the piston top.
When you remove that top plate with the slots, you see the top of the piston itself.
There is a circular depression in the center of the piston. In that depression are 4 holes that go all the way through.
There is a disk of metal that rides in that depression.
When the piston is moving down, the reed valve in the valve body above it has closed. No air can come back into the piston bore from that direction. So a vacum is being created in the piston bore. The air to fill that vacum has to come from somewhere.
What happens is that the circular disk you see there, gets pushed upward by the incoming air that is coming through those 4 holes. The air comes right past the disk, and then through those 4 slots cut in that cover plate. That allows the piston bore to fill with air.
Now, when the piston starts to move back upward, The bore is being filled with the piston itself. The air that is in the bore has to go somewhere...
That circular metal disk falls back down, and covers those 4 holes. That keeps the air from going back out the way it came in. So, the air goes the only place it can. It pushes up the reed in the valve body above, and goes past that, through the tubing, to the tank.
When the piston starts back down again, that reed valve falls closed again, and the whole process starts all over again.
Each time that piston moves down the bore is filled with air through the valve in the piston body. Each time it moves back up, that air is expelled through the valve body above.
~~~
Now, have a closer look at that pic. I have enlarged part of it and inset the enlargement.
Can you see that the entire area below those slots was so filled up with the crap that came from the body shop that it was a wonder this thing was moving any air at all ?
I drew two green lines. That outlines the crud that had built up between the piston depression, and the side of the metal disk. On just that side.
That disk was only just barely moving.
I cleaned everything up, put it all back together, and it now takes less than half the time to fill the tanks as it used to.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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That pretty much does it for the head.
My conclusions here are few.
I want to open up the incoming airhole. And I want to put a filter on there. Something that if they had done it, I might never have ended up with this compressor...
I want to open up the outgoing ports in the top.
While I am at it, I am considering polishing the ports. The kind of stuff they do in racecar engines. LOL Ait will flow more smoothly over a polished surface than over the pitted and pocmarked surfaces this thing has.
I want to drill and tap a port for filling it with oil. That port will simply be anywhere on the rounded shoulder of the top half of that crankcase clamshell. I will determine it's location once I have the clamshell open and can see the path taken by the piston rods and caps.
I want to take the entire thing apart again, check all the bearings. Completely clean it of all gunk everywhere. Then put it back together again, and see if it is improved at all.
A couple of things that I am considering...
The reed valve in the top of the head... I am considering taking the flat metal spring part of the reed out of there, cleaning it well with brake cleaner, then laying a very very thin layer of either pure silicone sealant, or some "marine goop" on that. Trimming it when cured, and putting it back in.
I am also thinking of doing the same to the metal disk in the piston top.
The reason for this is to create a better seal when they fall back down against their prospective valve holes.
I would clean the dickens out of the surfaces. Use some coarse sandpaper on the one surface. lay the silicone or goop down, and spread it out. Lay some saran wrap over that. then lay something flat on top of that. Something just heavy enough to almost but not quite sqeeze out all the silicone or goop.
That should leave a very thin even layer. And the silicone or goop will provide a more positive seal.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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crabby1
Reged: Oct 17 2006
Posts: 30
Loc: Narellan Vale N.S.W. Australia
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From Crabby1
Give some thought to the temperature the goop will be operating at before proceeding with that modification. If it gets too hot it may melt cause the piston to bind and damage the cylinder walls. A high termperature product marketed here in Australia called "GunGum" is used to patch small holes in car mufflers. It might do the job. Whats the cylinder? The base looks a bit like a LPG cylinder.
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I admit I am not aqquainted with the temp properties of the "goop" I described. I have no idea how it would react to the temperatures, and other conditions in that head.
That does not, however mean I gave no thought to those conditions.
I was leaning toward the silicone, not the goop. Ergo, I continued talking about the silicone, and the goop was hardly mentioned.
The silicone that I mentioned is what is called here in the states, "ultra copper". It is a product made for smearing on mating surfaces in an engine compartment to provide a seal.
It is advertised to withstand the heat of the exhaust manifold. As well as all the other chemicals and conditions found in an engine compartment.
Indeed, I have used it before on exhaust manifolds themselves. It does stay stuck. It does remain flexible. And all the different chemicals and conditions it encounters never phased it.
A couple of years later, when I went to take the exhaust manifold back off, the silicone was still sealing it as well as the first day.
It took some work to get the thinnest films back off of the manifold and it's mating surface on the block.
I might be interested in trading some "samples" of your gungum, for my ultra copper.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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