Well, this oil war has about run its course -- I have to agree with that.

I can live me a fine full life without knowing for sure if Rotella T dino 15w40 really can whup up on Klotz 15w50 synthetic on the temperature tests (although I suspect it would being a 15W40 oil and having better thermal conductivity on the high end accordingly).

We have learned that 15w50 oils of two respected brands can't conduct away heat nearly as well as a 5w40 oil can, and that was interesting thing to learn (and certainly unexpected).

Two very expensive brand names of "glitz" performance oils have come down a notch or two, in my mind anyway.   Certainly I question their performance vs their high high price even more than previously.

And Bill collected him a new nickname, one that reflects his "openess of mind" to any new ideas.  Billshut continues as he has before, undaunted by facts or data or anything else.  He never even connected on to the oil weight thing and never asked for or insisted on a retest using a lighter weight of Klotz oil (if they make such a thing).

Ah, such is life .....

.... as the song sez so well



"Hey Bungalow Bill .....  what did you kill?

Bungalow Bill ....





   he's the all-American bullet-headed saxon mother's son

He went out tiger hunting with his elephant and gun
In case of accidents he always took his mom

On further thought, my generator with its Briggs & Stratton engine does have a major difference from the S40. It is an old flat-head side-valve engine, so there is no oil circulation in its head. Thus the head temperature would probably bear little relationship to the oil temperature. It is also a splash-lubricated engine with no pressurized oil system. I could still assume differences in run time, pulling the same load, could reflect different oil friction in the engine. The engine is governed, so if oil friction increased, throttle opening would increase; fuel consumption would increase, and heat (temperature) would increase. Cooling air flow would remain roughly constant, since it is determined by governed engine speed. If I filled the little one-quart tank from a five-gallon can, I would eliminate most possible differences from fuel. I may yet do a little experimenting. Sure hate the idea of spending megabucks on exotic oils, though.

Webley still makes some fine air guns http://www.webley.co.uk/
The Briggs on the tank gets some amusing reactions. Most buy into it.

The whole "oil test" idea has been nagging at me, so today I went out and ran a "proof-of-concept" preliminary test, using my generator. I must stand corrected, though - I said it was a 2500 watt unit, but it is only 2400 watts. I mounted the little one-quart tank using cable ties, and ran a clear fuel line to the carburetor (this engine has a carburetor separate from the fuel tank, with a needle and float in it). I made a wire pointer and attached it to the throttle on the carburetor, then stuck a piece of tape to a convenient spot so I could see how far open the throttle actually is. I filled the tank, started the engine, and plugged a voltmeter into the outlet. 133 volts, unloaded. I marked the throttle position on the tape, then plugged in a 1000 watt heater. Voltage dropped to 125 volts; throttle opened up some, and I marked its new spot.  I unplugged the 1000 watt heater and plugged in a different one, unmarked for power. Voltage dropped to 123 volts; throttle opened slightly more than with 1000 watts. I marked that spot, too. Then I added the 1000 watt. Voltage dropped to 110 volts; throttle opened some more (but not quite to the wide-open mark I had previously made). I marked the spot. Somewhere in there I remembered to start a stop watch, but wasn't too worried about exact timing for the trial run. I walked away for about five minutes (noisy darn thing), and when I came back noticed the throttle had closed a little. Voltage was still 110 volts. My guess is that the engine and its oil warmed up during that time.

Under the full load the engine ran for right at 30 minutes. I had calculated it ought to run for somewhere in the 30 - 35 minute range, so was glad to see my calculations verified. I have not yet installed any temperature measuring stuff, but I am still strongly thinking about drilling the oil-fill plug and sticking a meat thermometer through it into the oil. I am also going to refine the throttle position indicator, and find a way to measure current.

The engine presently has 10W-30 oil in it, but I didn't write down what brand when I changed it last. I'll make my refinements, and run another test or two to see if things are reasonably repeatable. I have on hand both Rotella 15W-40 conventional and Rotella 5W-40 synthetic oils, so they will probably be the first ones tested. I also have some 5W-30, so it will likely be tried too.

I am thinking about the cross-contamination issue. When I drain one oil, some will stay in the engine to contaminate the next oil. I think I may keep the 10W-30. Then when I drain a test oil, I'll put the 10W-30 back in, run the engine for a few minutes, and drain. That way at least the cross-contamination will be more or less the same.

Anyone have any suggestions (that don't cost a lot of money, since I am retired and there was no COLA either last year or this)?

I have never heard of bungalow bill in my life.