Engines > Your Own Design
Junkers CLM
Roger B:
Thank you both :ThumbsUp:
A number of little bits now. First the retaining washers for the pull rod bearings then the start of the oil sump. I won't hollow it out yet but need it to close the hole when I test the scavenge system. I finally received the M3 x 20mm grub screws to correctly fix the scavenge piston. They are threaded into the top piston to retain the gudgeon pin with two nuts to hold the scavenge piston on top.
Next up is the drive assembly for the oil pump shaft and injection cam. This has to be removed and replaced over the end of the crankshaft and needs to allow adjustment of the injection timing. It is held together with 2 x M2 capheads.
Roger B:
I need a 12mm mandrel with a keyway to keep the gear and the drive sleeve aligned to drill the fixing holes. This was cut using the Proxxon mill. Then the grub screw hole in the drive sleeve which will keep everything (hopefully) in place was drilled and tapped M3.
Roger B:
Next I set up the Proxxon RT to drill the fixing holes. The helical gear is tapped M2. I then moved to the normal RT and mill to cut the timing adjustment slots.
The assembly was then put on the crankshaft to confirm the phasing of the keyway was correct before cutting the cam.
cnr6400:
:ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
Roger B:
Finally I could mill the injection cam. The profile is the same as I used on the two and four stroke 20cc engine. I don't think I need to be optimising injection profiles yet, just getting a runner is enough.
The flanks and the base circle were milled using the rotary table. The nose was finished by filling, using a radius gauge as a guide. Something was not quite right; I was expecting a 3mm radius according to the drawing but ended up with 5mm :headscratch: I will case harden it at the same time as I harden the cam follower.
It all fitted together without problems and there was sufficient clearance between the cam and the horizontal helical gear :)
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