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Hi Jim. I'm a long ways from you, but do you folks have a website or newsletters or anything that chats about your projects or activities? There are some guys within a couple hours of me (Calgary, Alberta) who have done some model engine casting in the past & hopefully will again soon, but...

I was always curious about those Cameron's. Can anyone explain what is occurring when spindle/chuck runout is being dialed in? They say the spindle runout is 0.0002" & its a JT0. I think that's a 1.41-deg per side taper, meaning the chuck or collet has a matching angle socket profile, right? The...

Thanks for catching. Corrected. Where is AI when you need it. OTOH, while re-boring the ID, there WAS inner fear, LOL.

I made a new shaft with an integral end flange to retain the gear cluster that way. The advantages are it eliminates the bolt & washer business which could come loose one day & runs dangerously close to the back of the ring gear plate as is. The disadvantage is that the shaft is somewhat...

I never really cared for this washer/screw arrangement but assumed it was necessary for disassembly, but it actually isn’t. The crankshaft can just exit from the rear with its gear still on the shaft & disengage from the idler gears axially. My temporary conclusion was that the steel gear...

A few more pictures to get caught up to present day. On subsequent running sessions, the engine continued to smoothen out & I could also reliably hand start if still warm. The cylinder flange bolts remained tight & no more valve/piston competition for the same real estate But I had another...

I made sets of brass head shims from various stock thicknesses just in case.

So, I commenced measuring all the contributing dimensions (there are many). Rod throw, piston height, cylinder deck height, cam lobe rise, valve clearance… Everything was within a thou of drawings. I did deviate slightly from drawings by decreasing the valve seat width, but net effect actually...

The exhaust valve indentation on the piston tops was a serious issue to address. My first suspicion was that I had incorrectly placed the ring gear cam plate assembly onto the idler gear cluster off by a tooth. This would have the timing effect of lagging the exhaust valve closing beyond TDC...

I actually made a tester Teflon gasket for under the cylinder flange earlier but elected to omit them initially. I wasn’t too keen about using Loctite on the threads if it could be avoided. I sourced some 0.002” thick sheet so it wouldn’t affect CR very much. As it turns out, the gaskets did...

After subsequent runs it was becoming obvious the drill starter had to go. It continued to chew the prop and had more difficulty turning it over as compression improved. I also suspect as the engine began firing, the drill’s gear drive was probably limiting it from free running until I could...

Remediation. First the easier stuff. Here is my initial makeshift drill starter. It mostly turned the engine over OK to where it would fire, but the prop engagement pegs were mangling the delicate trailing edge root despite my attempts to rubberize it with tubing, heat shrink & electrical tape...

The #1 piston assembly looked pretty good overall. Lots of lubrication, no shiny wear areas or hot spots. The ring looked like it was just starting to wear in evenly enough around the periphery. A few vertical scratches on the piston here & there but nothing of consequence. However, I noticed a...

Crankshaft & rods

General Parts Condition

On my last runs I noticed a few cylinder flange screws loosened again after I had already tightened them the prior run. This may have been contributing to what my ear said was rougher running. One of my pushrod tubes was starting to jiggle around, probably as a result. Another good reason to...

I think I did about 5 runs of a couple minutes duration each. I didn’t want to push my luck any further the first outing. Mostly what you will now see is lots of oily pictures from initial teardown. The components looked acceptable, but I also discovered some near miss problems which I’ll...

Apologies for my posting lapse again. Well, the day finally arrived with the realization that I somehow had come to the bottom of my seemingly endless To-Do list. There was nothing left to make. After <ahem> ‘a number of years’ it’s a rather weird feeling. My preference was to attempt a run up...

Test video upload

Not really your question but post #280, I made a leak down tester from readily available Amazon parts. I subsequently discovered others on the forum have made similar ones before me. I think they are a worthwhile diagnostic tool, especially for multiple cylinder engines where you are comparing...