So after the first run, shortly followed some sort of failure, I let the engine cool and started looking at the issue(s).
I noticed 2 things right away. I could see the teflon gasket material budging out of the valve block assembly and I noticed that the engine had no compression when turning it over by hand. I was hopeful that the two things were related. So the first thing I did was to take off the valve block and tear it apart. Here's what I found:
I had used .005 teflon sheet, thinking that I was clever
but that definitely wasn't the case. Teflon is supposed to withstand high temperatures, but it apparently looses strength and with some pressure applied it just flowed out the joints between the blocks. Luckily, back when I was getting my Silhouette cutter setup, I cut some additional gaskets out of FelPro paper/fiber material and had a couple of gaskets cut from some 1/64" material. So I installed those gaskets and reinstalled the valve block on the engine.
I could immediately feel that the compression had returned when rotating the flywheel by hand, so my hopes were up! I did in fact, restart the engine after a bit of putzing around and it ran, but as before, only at mid range rpm and it wouldn't idle or go to any higher rpm. So I shut it down again and started looking at things.
I found the Traxxas carb settings guide and made sure that the carb was set to the factor settings. Then I looked at the exhaust valve timing and it looks to be set exactly as specified. But I then checked the ignition timing and it was set to almost TDC or maybe even very slightly after TDC. So I reset the ignition timing to about 10 or 12 degrees BTDC which is a bit more advanced than the plans call for, but seems to be a common recommendation for non-advancing type ignition systems on model engines. I really came to appreciate Roy Scholl's ignition system during this work as the LED timing light was invaluable!
Then I started the engine one more time and noted that it seemed to start a bit easier. I also noted that I could idle the engine down and accelerate it to higher rpm fairly easily. I spent a fair bit of time playing with the main jet and ended up leaving at the factory setting. I did set the idle stop and slightly enriched the idle mixture on the carb and got it run as you'll see in the next 2 videos.
This is the engine running at low rpm. I had to hold my finger on the throttle to keep it closed as it wanted to vibrate open.
And the engine running at high rpm. The throttle seemed to stay at this position fairly well. I could actually get it to run a bit faster, but I had to just ease the throttle open just a bit more and it wouldn't stay there.
So, I"m calling this engine a success!!
I still need to clean it up a bit and get it mounted on the mounting board.
So, I want to acknowledge and thank some people.
Mr. Webster for his excellent plans!
Roy Scholl for his excellent ignition system!
All the previous builders that gave so many great hints in their build logs!
All those watching this build log and offering encouragement!
And a special thanks to Brian Rupnow for his starter hub design and 'Setting Up and Running Guide"!
I hope everyone has enjoyed following along during this build!
After I get the engine properly mounted, I'll take a better video and post it over in 'The Showcase" forum under 'Engines'.
And yet again, thanks to everyone for following along.
Enjoy!
Mike