Valve temperature of a small i.c. engine

[Brian Rupnow]

Well, since you have succesfully built the more exotic tool its a moot point, but there is no "self centering" to it---Thats why it has the pilotted end---to keep it from self centering.

 

[Metal Butcher]

Brian, the pilot does self center the 4 cutting edges, to a degree. With only two cutting edges, one edge could grab and deflect the cutter off center at 90* and more so than a cutter with four. Bearing in mind that this is a hand cutting operation and there is no machine spindle to assist, like on a piloted counter bore. Unfortunately the .094" pilot is not very rigid, just like small drill bits and end mills.

-MB

 

[compspecial]

MB
I did not mean to worry you unduly by mentioning "red heat" I worked on small air cooled engines for many years and many failed due to lack of compression caused by exhaust valve clearance closing up from the paltry 6thou specified by the makers, but I NEVER saw one burn out, simply ground a bit off the stem and re-lap. It seems the smaller the engine the less it is stressed thermally or otherwise. thanks MB.

 

[Metal Butcher]

MB
I did not mean to worry you unduly by mentioning "red heat" I worked on small air cooled engines for many years and many failed due to lack of compression caused by exhaust valve clearance closing up from the paltry 6thou specified by the makers, but I NEVER saw one burn out, simply ground a bit off the stem and re-lap. It seems the smaller the engine the less it is stressed thermally or otherwise. thanks MB.

compspecial, you didn't cause me to worry at all. I'm finding out things about IC engines that I never knew, and were never mentioned before I started my build. Just to be sure that I'm doing it the right way, I made up steel exhaust valves. Not a big deal since they were quick and simple to make.

Thanks for your input.

-MB