Okay, test results are in!

And they are not what I expected.

First some observations and conclusions:

1) I think Metallica Junkie may be correct, and that was raw fuel dripping and not oil. I have no clue why it would drip raw fuel after the engine shut down because the fuel tank ran dry. But in any case, there is no excess oil in the crankcase.

2) The loss of 1100 RPM was due to the restrictive nature of my ring collector Version 2. Not because there was excess blow by oil in the crankcase being whipped up by the crankshaft and weighing/slowing down the crank.

3) The tube inside the exhaust outlet does not cause a restriction in the breather. It does not cause back flow or back pressure. It does not suck, it does not blow. In fact, it does absolutely nothing. Zero. It is merely an extension of the silicone hose attached to the drain nipple.

4) The blow by oil seeping past the pushrod tube bases on #1 cylinder that I observed was not because the crankcase was full of blow by oil and it was being forced out the base of the pushrods. I believe now it was simply due to increased back pressure of the exhaust system.

Bottom line, is the engine ran slower on Collector #2 simply because it is a more restrictive muffler than Collector #1.

And that is not necessarily a bad thing. I have wanted to test the largest prop this engine is rated for, a 22". As you know, the slower a radial turns the more authentic it sounds. I am thinking I can use this muffler in conjunction with a 22" prop and get the thrust needed to fly a plane and turn the engine slower for a more authentic and pleasing sound. So I am not going to scrap this collector!

The reason it is more restrictive is because I inserted the exhaust stubs 1/4" deep into the ring. Collector #1 has them inserted only 'maybe' a 1/16".

Anyway, I did the bubble test. So as not to have prop blast blowing everything I ran the engine with just a stub of a prop. The line did not blow bubbles, and it did not draw up any water into it. No matter the RPM.

I next ran the engine with the propeller I have been using all along, an MA 18x10. With the drain line not connected to the exhaust pipe, the RPM was the same as yesterday when it was connected.

To save time, I did not remove the engine from the mount, but I did pull off the collector ring and ran the engine again with straight open pipes. I got back the RPM it had lost. I forgot to observe the drain line when I shut it down, so I don't know if there was any after drainage. (Maybe it's on the video.) I did observe the #1 pushrod base when running without the collector and there was no blow by oil seepage thee.

I will process the video and upload it later today.