Thought I would take care of the oil pump. Most people that work on piston engines are familiar with the term "blueprinting". I guess you could say, that in some ways, this is what I did to this oil pump.
I have several different manuals that I refer to for OX-5 work: The Curtiss manual, which is pretty basic, a manual from the Richfield Oil Company, which is much better, and one from Miller - a company that made OX-5 upgrade components. It's interesting when you read what the Curtiss manual has to say about the oil pump. "The oil pump should be opened and examined, although there is little chance of trouble here". I have to take issue with this. First of all, I would rate the oil pump as one of the more critical components of any engine - just like the heart is to the human body. This is especially important with the OX-5 because of the screwy way the oil is sent thru the engine. Oil is sent thru the camshaft first, then to the main bearings. I feel it should be the other way around. Secondly, I did find "trouble" with my pump!
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| Oil pump components |
The pump is a simple gear-type pump made up of the components shown is this photo. The first problem I found was the clearance between the bronze idler or driven gear and the shaft it rides on. The clearance was .0079" - way too much! The other shaft on the drive gear had a clearance of .0015" - acceptable. So I turned a new shaft on my lathe with a .0015" clearance and pressed it in the housing.
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| Driven gear on new shaft with .0015" clearance |
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| Checking clearance between gear teeth and pump cavity |
Specs from the Richfield Oil Company manual call for .002" endplay of the gears, and .002" clearance between the gear teeth and pump cavity. Either of these out of spec would affect the efficiency of the pump.
A piece of .001" shim stock revealed the clearance between the gear teeth and pump cavity very close to .002" - OK here.
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| Confirming end play with Plastigage |
I wanted to dial in the end play as close to .002" as possible. First was getting the gears to have the same height. The bronze driven gear measured .3737" and the steel drive gear measured .3748", or .0011 higher. I machined the drive gear to the .3737" dimension, so they now matched. The cover was not flat, so I lapped it on a glass plate.
After checking the depth of the pump cavity, it showed I needed a .008" gasket to get .002" endplay. I made a gasket this thickness and checked the clearance with Plastigage and it came out right on the money!
May seem like a lot of work, but I thoroughly believe it is worth it!
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| Original harness |
Then it was on to the ignition harness. I need this done to test the magneto which I should be finishing soon.
I had the original harness, so it was just a matter of cleaning everything up and making new wires. In my attempt to keep things as original as possible, I ordered 7mm, cloth-covered spark plug wire.
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| All the components ready for assembly |
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| I had to make one new terminal plug housing to replace a broken one |
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| These are the original Rajah spark plug terminals. Note the patent date of Feb. 21, 1905. Very Cool!! |
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| Had to make a special tool to remove the plugs on the magneto end |
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| Installing terminals on the magneto end |
Assembly is easy. After the ends are stripped and tinned, it's just a matter of installing the terminals.
On the magneto end, one half of the terminal is slid over the wire, a loop is formed in the wire, the housing slid over the end, and the plug screwed on with the special wrench.
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| Rajah terminal soldered on |
On the spark plug end, the Rajah terminal is soldered on to the end of the wire.
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| Voila! A finished harness |
Not sure what's next. I doubt I'll see the capstrip material, but my second coil/armature for the Berling mag is done so it may be magneto work!
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