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Ernie Weinberg Boynton Beach, Florida firstname.lastname@example.org
After building several single cylinder Jan Ridders’ engines, I felt ready for a multi cylinder, so I purchased a set of plans from Dale Detrich. This is a completed four cylinder engine built by Dale.
And what a set of drawings. Totally complete with hundreds of construction pictures on a CD. After review I thought it best to make what seemed to the most difficult part first, multi lobed crankshaft. So, after several tries here’s how I did it. Make the jig then using 12L14 steel turn in the lathe as follows:
Crank shaft after the first turnings.
Making cams with CNC is quite easy. I drew the cam in AutoCAD to define the tool path. It’s then exported to Mach3 (CNC software) in the mill. I clamp a ˝” round piece of steel about 4” long vertically in the milling machine vice. The milling is started at a depth of about 1/8”. The milling process is repeated until 1” of cam is exposed. That defines a pair of cams. The center hole is drilled and reamed.
The part is removed from the mill and placed in the three jaw chuck and parted off to the required length. Then the same 1” piece is returned to the mill and the process is repeated three more times.
Four cam pairs
Placing Cams On the Shaft & Setting the Timing.
This procedure was developed by Dale Detrich, which I refined slightly.
Position the first cam pair on the cam shaft and solder.
Place the timing chart in the tail stock with the 180 degree mark at the top; do not rotate the chart thought the process.
Position a dial indicator as shown (on the left).
Put the shaft with the first cam pair in the chuck, just a little tight and rotate the shaft so that the peak of the cam is zeroed on the indicator. The peak of the cam is at 39 degrees. Tighten the chuck. Rotate the pointer to the 39 degree mark on the chart.
Next, rotate the chuck so that the pointer is at 129 degrees. The next cam pair is rotated so that the peak is zeroed on the indicator. Solder the cam to the shaft.
Next, rotate the chuck so that the pointer is at 141 degrees. The next cam pair is rotated so that the peak is zeroed on the indicator. It's soldered.
And finally, rotate the chuck so that the pointer is at 231 degrees. The next cam pair is rotated so that the peak is zeroed on the indicator. It's soldered.
The final product, total time to make it, about three hours.
This is what Dale Dietrich's engine looks like after several months of making chips. It's starting to look like an engine. I certainly learned a lot even after six years of making these things. And I owe it to the people I have been emailing. This afternoon I have to go to a local hobby shop and get a 1/4-32 tap needed for the spark plugs. Then I need to get the plugs from Dale as I think there are too difficult to make. Lots of other parts that I did not assemble yet and are not shown
Copyright 2010, Florida Association of Model Engineers and engine builder as noted above, All rights reserved.