"synthetic" oil causing two stroke cylnder "glazing" ?

[Tmoose]

http://www.legendperformance.com/technical-info/

"The most notable disadvantages of synthetics are high price, poor off-season rust protection, irritating smell along with eye and respiratory discomfort due to the solvents used in manufacturing and loss of ring seal due to “glazing” of the cylinder walls with extended use. After several years of intensive research, we have documented that the use of synthetic 2T oils will in fact cause the cylinder walls to “glaze over” and cause “blow-by” at the piston rings eventually resulting in a power loss. "

 

[MikeHalloran]

I wouldn't have guessed a ring-ding's cylinder walls would last long enough to glaze.



Mike Halloran
Pembroke Pines, FL, USA

 

[dgallup]

That article seems to be specific to air cooled snow machines, of which we have precisely zero in South Carolina. However, I have a lot of personal experience (not professional) with air and water cooled two stroke motorcycles (dirt & street) and outboard engines going back over 50 years. I have never experienced any of the so called disadvantages of synthetics other than price. I've gone through the entire history of the lubricants in the article and consider modern synthetics a huge improvement. Some of my outboard engines have gone well over 20 seasons of use.

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[Tmoose]

Bombardier is (or at least was) pretty emphatic that oil with a TCW (w for watercraft) rating is not suitable for their PWC Personal Water Craft.
"Bombardier requires that an API-TC oil be used in their engines" and cite why. "Rotax marine engines evolved from their very successful snowmobile and motorcycle racing designs. These engines produce more power/cc than any other PWC manufacturer’s engine. Rotax designs these engines to work harder and run hotter than other brands. They simply need more protection than TCW3 oils can give."

http://www.sea-doo.net/techarticles/oil/oil.htm

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The oil that Legend Performance (authors of synthetic = glazing report) offers with a non W TC rating is ZX-2SR. Apparently it takes at least a dollup of Castor bean to do it, as they say it has a "distinctive “Racing Castor” scent."

I think for my poorly ridden vintage air cooled off road bikes I'll stick with TC rated Golden Spectro blend.

http://www.spectro-oils.com/wp-content/techsheets/GSMC.pdf

Although in a desperate attempt to re-live my "glory days" I've begun a search for a local source for Blendzall just for the exhaust aroma therapy. The Yamaha Yamalube racing 2 stroke oil does not mention castor any more.

 

[drwebb]

The very term "synthetic" when describing lubricants is NOT a technical definition, but a marketing term. So they are making a marketing claim (possibly based on "intensive" market "research"), and should be evaluated on those merits.

From a technical perspective, what is marketed as "syntehtic" for 2-strokes can describe formulations put together with polyisobutlyenes and/or a whole variety of syntetic esters, each of which has vastly different chemical and physical properties. And as alluded above, the claim seems unlimited by application or duty cycle. Seems pretty vague. Not sure what TCW-3 vs. API TC has to do with it either. Is there a question here, or just an observation that folks say all sorts of things to sell lubricants?

Castor oil has good lubricity, but I suspect if used in effective concentrations it may carry a significant ring-sticking debit that could preclude it from passing the more stringent 2T engine test specifications.

 

[dgallup]

At one time synthetic lubricants did have a technical definition until some idiot judge made a ridiculous ruling. What finally evolved from all this confusion was that the label term "Synthetic" is a marketing term, and therefore it is up to the "marketer" of the oil, to define what "synthetic" is.

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[drwebb]

OK, so I scanned the article and they do refer specifically to both PIB and esters as being synthetic, and brightstock as not. However, they also claim:

"The PIB is part of the man-made synthetic molecular structure that inhibits ring seal on engine “break-in” and leads to glazing of the cylinder walls. The reason for this lies in the fact that some of the synthetic molecules “high molecular weight” and chemical compounds (sulfur) cannot combust completely and thereby leave a residue on the cylinder wall."

Well, if you look at most any product data sheet, brightstock is loaded with sulfur, whereas PIB and esters have little if any. Next they ascribe solvent content to driving up formulation cost, which is also backwards. There's 2 factual errors right off the bat- take the claims for what they're worth.

 

[romke]

"glazing" usually is attributed to running extensively at low temperatures, so the lubricant used is not fully burned. that may indeed lead to deposits (a thin layer) on the cylinder surface, effectively "smoothing" it, so the build up of a suitable lubricant film will be more difficult. i guess the problems encountered have more to do with the actual operating conditions then with lubricant composition in this case.

 

[TheBlacksmith]

Back when I rode snowmobiles we rode Ski-Doos (Bombardiers) and used their Blizzard 50-1 racing oil. Low temperature/low speed operation was not a big concern for us! Despite that, over the course of about 10 machines, we blew two head gaskets and scored one piston (the latter when running 50 mph in slush on a 45 degree day) all on different machines/engine sizes. I'd say the oil worked, so if in doubt use what the manufacturer says and /or sells.