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100 years old and there's probably 100 years left in it.

Ok I'm comfortable with how things fit together now. Going this far in CAD before cutting stuff has avoided a few junk parts already, and was worth it. The pulleys were too large and intersecting. Now it's fine. I'm going to start on the front crankcase tomorrow.

ah gotcha. Same kind of deal. Thanks!

why 8 degree steps? If I use 9, I can use my 40:1 dividing head always going back to the same hole.

The way I do it is use whatever lathe is handiest to cut the spindle side mating feature (threads in this case). Then remove it and install the un-finished adapter onto the spindle it will mate with (the HF in this case), then use that machine to cut the chuck side feature. On the case of...

Yeah its totally colliding. The timing is off by 15 camshaft degrees or so.

I spent some time with the rest of the head in order to get an idea on valve timing. I decided to copy the Whippet plans i had for the cams and valve timing since it was the same bore, stroke, and RPM target, which means each valve tilted 55 degrees from vertical at TDC to set the timing and a...

Absolutely. I've been updating the 3d model and drawings to reflect changes as I go. I can't promise the drawings will match drafting standards but at the very least I add dimensions in as I find them missing.

it's the student edition of Solid Edge

I took a break from cutting metal and spent a few days modelling more parts of the engine. I've got some questions about where I'm going to mount magnets and sensors for the ignition, so I'm going to make sure I don't need either the front or rear case as a mount point before I start making...

Awesome thanks! The numbers do help me adjust my "right" part of "that looks about right"

Hmm I see what you mean. That looks like a good rule to follow, thanks!

darn, I forgot to provide some way for the head to locate on the cylinder bore. I guess I'll use dowel pins or an external fixture for alignment while torquing the head bolts if I don't like the bolt slack. I guess I can always take the liner out and shave a bit off the lip to make a recess for...

Ah I see. The valves are passing each other in opposite directions so it should be reasonably easy to see when they'll collide. One of those trees I missed while looking at the forest. Thanks guys, I'll abandon the mismatched valves and make them the same. I can always make another head when...

yup, slid in easy, and once cool it didn't move a single bit from the fin turning. Thanks for the guidance.

Starting to look like my imagination now. What's for dinner? Engine block. Sleeve in Back on the lathe on the undisturbed mandrel. Borrowed the wife's lightbox.

Can someone point me in the right direction for valve design for a 4 stroke IC engine? interested in valve diameter, port diameter, and valve lift. Generalities and rules of thumb for my first engine design would be fine I think but I'd like to try to make some informed decisions instead of...

that's a good point, it's an auto-advance CDI. 2 magnets on a camshaft it is! Thanks! That gets me thinking...Maybe I can repurpose the timing belt tensioner for this. Make it 2x the crank pulley and drive it, and stick 2 magnets in it.

I've got an ignition system from an RC gas two stroke, designed to fire once per crank rev. Does this mean I should be running the magnet and sensor off of a camshaft? Or will it work ok if I let it fire every rev and waste a spark at the top of the exhaust stroke?

p.s. if anyone's curious about what a horizontal mill can do that is harder on a vertical mill, imagine facing that angle plate with a fly cutter. You'd need a really deep vise, and one that tolerates an angled part (the angle plate has some draft). Or use another angle plate that's already been...