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07-18-2019, 01:10 PM | #21 |
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Re: Mixing synthetic and regular oil
Aviation is where the ester based synthetics started out for high temperature operations in turbine shaft and turbojet engines. Using mineral oil in them would be a disaster. In reciprocating aircraft engines, they tried straight synthetic oils but had problems so it was discontinued. Aircraft engines run hotter than the automotive engines due to them being air cooled.
Some of the misconceptions likely came from those problems but they have what are called semi-synthetics now. The engines would fail with those oils in the helicopters down here in Texas. They can only use straight grade 100 SAE 50 oils if they want them to last to TBO. Airplanes can and do get up to altitudes where the temperature is down right cold so it works OK for the most part. Helicopters general stay down low where there is better density for lift. Last edited by rotorwrench; 07-20-2019 at 09:25 AM. |
07-18-2019, 03:03 PM | #22 |
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Re: Mixing synthetic and regular oil
oil "base" stocks don't differ much in their own category (synthetic or petroleum). The rub comes in downstream, each manufacturer (for lack of a better word) adds their own additive package/chemical magic to those base stocks.
I'm not a chemical engineer so I don't know what happens when you "mix and match". My .02?? I think this falls in the same category as guys trying to raise the octane rating of gasoline using off the self chemical stews. |
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07-18-2019, 03:06 PM | #23 |
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Re: Mixing synthetic and regular oil
all I'm saying is those guys are a hell of a lot smarter than I am
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07-18-2019, 09:21 PM | #24 |
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Re: Mixing synthetic and regular oil
Lot of different oil options. Royal purple has some stuff with high zinc ratings. Or using a semi diesel straight 30w. Thick though.
Pertaining to the comment "I think this falls in the same category as guys trying to raise the octane rating of gasoline using off the self chemical stews." Not sure why anyone would need to boost octane on a standard or slightly modified flathead. Octane in the 30s,40,50 was around 70 octane at best. Octane in the 20s was around 40 and gas was dirty. There is a reason I can get a hit and miss engine to a running heat and switch it to fire on kerosene (15 octane). Last edited by Tinker; 07-18-2019 at 09:38 PM. |
07-19-2019, 09:06 AM | #25 |
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Re: Mixing synthetic and regular oil
Tinker
I'm not suggesting any of us would want to raise the octane running a flathead. What I am saying is some people [itinerant racers mainly] attempt to raise the octane [essentially reformulate gasoline] using chemical stews available at the local parts store. Pure snakeoil. That is in the same vein as people mixing oils; the home hotrodder outthinking engineers and oil companies who have spent many years and bazillions of dollars developing additive packages. But hay, whatever turns your crank. |
07-19-2019, 11:13 AM | #26 | |
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Re: Mixing synthetic and regular oil
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07-20-2019, 12:52 PM | #27 | |
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Re: Mixing synthetic and regular oil
Quote:
It's the only Mobil 1 that has the full amount of zinc for flat tappets. It being synthetic makes it work better in the cold, and stands up to heat a lot better... hence the reason using it in air cooled engines that tend to cook the oil. I've used it for decades in these applications. The 15w50 is also thick enough for flatheads, as I don't feel comfortable running thin stuff in these engines. Very affordable in the 5 quart jugs from Walmart, Advance Auto parts, Autozone, etc. My $0.02 Good Luck!
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07-20-2019, 03:50 PM | #28 |
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Re: Mixing synthetic and regular oil
You are correct Mike. To the best of my knowledge, all oil that is at least 50 weight has high amounts of zinc. I started using it when I had a case left over from my dirt track days. The hemi in my racecar had an enlarged oil pan, dual filters and a large oil cooler when meant it took 13 quarts of oil for a change. When I built the car, all the old timers told me "hemi's need lots of oil". Changing the oil in that car was more of a financial decision than anything else.
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07-21-2019, 09:40 AM | #29 |
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Re: Mixing synthetic and regular oil
With the racing oils, I think Mobil puts more zddp in there than is actually necessary for all but racing. Most all the figures I've seen on the subject put the nominal useful value at 1200 ppm per container for best anti wear results. Amounts above that actually start to get relatively acidic and can affect other materials in the engines. A person has to keep in mind that the stuff is made for racing with very hard use and constant oil changes and not for normal driving and setting for several months in the garage. I'm not saying a person shouldn't use it but be aware of what it's really for.
Last edited by rotorwrench; 07-21-2019 at 09:46 AM. |
07-21-2019, 10:02 AM | #30 |
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Re: Mixing synthetic and regular oil
High zinc levels and detergents "don't play well together" is what the applications engineer at the Lucas Oil booth said. That's why the racing oils aren't meant for on road use. He said racing oil has little or no detergent and should be changed very frequently.
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07-21-2019, 01:43 PM | #31 |
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Re: Mixing synthetic and regular oil
Synthetic oil is light years ahead of conventional oil, but beware that one of the qualities of full synthetic is its ability to flow.When we rebuild an engine we advise the owner to avoid full synthetic on early engines as it can, and does, leak around the crank seals
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07-22-2019, 08:26 PM | #32 | |
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Re: Mixing synthetic and regular oil
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I think we agree?, I can come off sometimes being serious when I'm not. "Racers" certainly have cause for increasing octane ratings. Drag in my thinking. As far as a regular old flathead, MMO shots in the gas never hurt. Pertaining to fuel in my flathead anyway. Not that I'm buying cases, but always have a couple bottles. MMO does nothing to the octane rating. Just a little help to lube the valve assemble. Just something I do once and a while. as far as oil, see I posted here #15. Explains my thought. Just change it. . Last edited by Tinker; 07-22-2019 at 09:24 PM. |
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