After completing the disassembly, I started restoration with the parts that were in the worst condition. Without a doubt, the gas tank and oil pan were first on the list. The oil pan was a bit worse off than the gas tank since the 6′ steel pry bar had rested on it during removal of the piston, so there was a nice big divot in the middle.
The best option for this part was a straight replacement, so I opted to make a replacement out of sheet stainless steel. Since I had never worked with stainless before, I soon found out that ‘simply cutting some holes’ wasn’t so simple.
I started by marking off the outline of the pan on a nice sheet of sheet stainless. (picture 1) (picture 2) I used our power shear to cut it to size, and the grinder to shape the corners off. The next step was to drill the holes for the bolts- that’s when I started to appreciate how hard this stuff is to work with!
I had to drill 8 bolt holes and 2 1″ holes for the gas fill and pickup lines. Even with excessive amounts of cutting oil, I was able to drill only 1 hole at a time before having to resharpen the drill and you can see how that went!
The 1″ holes weren’t any easier at first… I tried to use a pilot drill with a High Speed Steel fly cutter which ended up barely marring the surface and completely flattening the tip on the fly cutter.
So the next idea was to use a full size drill… which had less than ideal results:
To clean it up I used a chisel and hammer to round off the edges of the hole. The finished hole looked like total crap.
A week later my grandpa suggested trying a device called a chassis punch (I think) which is used to punch holes in electrical boxes before they came with knock-outs.
He pulled a 1″ chassis punch out and viol-la it was the exact size of the Bigger holes that I had chiseled out the week before. It was actually slightly bigger, so I was able to clean up the holes with the punch. I also used a smaller punch to clean the bolt holes.
With the holes made, the next thing to do was attach the oil strainer, which looks like a tuna can with a screen at the bottom and a metal shield at the top. The flyweights on the governor sit right above this can in the crankcase and dip oil out to sling on to the other parts of the engine while it is running. The strainer can was spot welded to the old oil pan in 3 places. I ground the spot welds off from the pan side and cleaned up the bottom of the can after it was removed. We do not have a working spot welder, so I drilled 3 holes in the can and used a nickel rod to weld it into place. It didn’t take much, maybe 3-4 seconds of weld per hole. I was quite impressed with my welding success. Thin materials easily go from perfect weld to nasty hole in less than a second. Check out the results:
Click here to see the bottom side
And click here for an overall finished pan.
Even though I thought that was the end, there was a slight problem when I got to the assembly phase: The stainless that I used was slightly thinner and more flexible than the old steel pan, and would not seal on part of the gasket. I just finished welding a few pieces of flat bar to reinforce the 1″ holes to get them to seal to the bottom of the crank case. Pictures later.
That’s it for the pan. Next up will be repairing the governor shaft, flyweight, and exhaust valve rocker arm.
