Petroleum better than Synthetic in some applications?
- Thread starter yellow68
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quote:Maybe so. I did not ask them why. I just figured they knew best. I think that eventhough everything in my engine is new that the old design was not made for a slippery synthetic. Meaning if there is a leak path then it will find it.I don't think it is a myth that synthetic oil can make a engine leak. I have seen it. I will ask them and let you guys know.
Originally posted by GSV: Did you ask them why? Sometimes their reasons are just plain ridiculous. I had a guy at NAPA tell me Synthetics leave the engine parts bone dry at startup where conventional oil clings to the metal.![[Cheers!]](/forums/graemlins/cheers.gif)
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Most engine builders will tell you not to break the engine in on synthetics. But I have never seen an engine (in good condition), leak with synthetics, that did not leak with a conventional. I have run synthetics on rebuilt (improved ![[Big Grin]](images/icons/grin.gif)
) engines for years and have never had a problem after a break-in with a conventional oil.
) engines for years and have never had a problem after a break-in with a conventional oil.
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Engine rebuilders are often not tribologists
Some engine rebuilders exist to rebuild engines
There are some lousy, worn out engines that don't warrant synthetic usage.
F1 engines use synthetic oil. Enough said.
quote:mazda used to recomend this because the synthetics didn't burn off as well as the dino (kind of a direct injection thing).
Originally posted by uconn1150: For whatever reason (and maybe someone like Molekue may know) but Mazda forbids use of synthetics in their rotaries...
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quote:I've heard this a few times but don't get it. The only 2 cycle lubricants that do burn cleanly are synthetic...
Originally posted by tweeker43:quote:mazda used to recomend this because the synthetics didn't burn off as well as the dino (kind of a direct injection thing).
Originally posted by uconn1150: For whatever reason (and maybe someone like Molekue may know) but Mazda forbids use of synthetics in their rotaries...
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quote:I've run synthetics early on and had no ill effects. Run dino for 100 miles as a "flush" after the rebuild, then fill with synthetic and drive like normal. It's always worked for me... [ October 14, 2003, 11:49 PM: Message edited by: jsharp ]
Originally posted by sbc350gearhead: Most engine builders will tell you not to break the engine in on synthetics. But I have never seen an engine (in good condition), leak with synthetics, that did not leak with a conventional. I have run synthetics on rebuilt (improved
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quote:The rotary engine is different. Oil is in the combustion chambers at all times, therefore burns off slowly. Synthetics are more resistance to burning (in motor oil form, not 2 cycle), so they thicken more and more. Or so I've been told.
Originally posted by jsharp:quote:I've heard this a few times but don't get it. The only 2 cycle lubricants that do burn cleanly are synthetic...
Originally posted by tweeker43:quote:mazda used to recomend this because the synthetics didn't burn off as well as the dino (kind of a direct injection thing).
Originally posted by uconn1150: For whatever reason (and maybe someone like Molekue may know) but Mazda forbids use of synthetics in their rotaries...
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My understanding of the RX7 (I owned 2) is that a small amount of oil is injected at startup, and only at startup. I'd use a quart every 3000-5000 miles. Seems SOME synthetics didn't work well with this injection system; thus as a blanket policy all synthetics were banned.
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For what it's worth, this was snatched from Mobil 1's website:
Question: My Isuzu owner's manual says not to use synthetic oil. Can I use Mobil 1?
Answer: This restrictive statement is only found in owner's manuals for Isuzu vehicles with heavy-duty diesel engines. The diesel-powered NPR and NGR commercial trucks are the only models affected in the U.S.
Isuzu has advised us that they state "Do Not Use Synthetic Oils" because of poor seal compatibility observed in the past with synthetic oils based on diester base stocks that have been marketed by specialty companies. While they assume that synthetic engine oils that are polyalphaolefin (PAO) based – such as Mobil 1 with SuperSyn™ or Mobil Delvac 1® – provide excellent performance, they have maintained this language in their owner's manuals. They are not currently willing to list Mobil 1 or Delvac 1 in their owner's manuals as approved synthetics. Should you choose to use Mobil 1 or Delvac 1, use Mobil 1 with SuperSyn™ in a light-duty diesel wherever an API CF or CD quality oil is called for, and Mobil Delvac 1 where a CH-4 quality oil is called for, as in the Isuzu vehicle product line.
