Question for the older guys..

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4,478
Location
Southern California
Castor oil is superb in high temperature applications but has one nasty habit - its molecular structure changes after being heated and it congeals to an unpumpable, undrainable gell at cooldown. If it's allowed to cool to ambient temperature in the device, that device has to be disassembled and the goop literally dug out. Castor oil was used for WW-I aircraft engines as well as early race cars. In addition to prompt engine drains for those pilots fortunate enough to make it back from a mission, the lack of valve covers meant the pilots were constantly exposed to castor oil mist. Those brightly colored scarves the pilots wore weren't merely for jaunty show - they protected the pilots' mouths and nostrils from excessive exposure to the oil mist. Even at that, the pilots still ended up with strong urges by the time they landed. Latrines were thoughtfully provided near the end of the taxiways for those really regular guys. In that era there were old pilots and there were bold pilots. There were no constipated pilots, though.
 
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336
Location
White House, TN USA
It was, for it's day, a superb racing oil. Racing oil because race engines were torn down and rebuilt after every race day. Using it on a street engine produced an extremely hard carbon deposit in piston ring grooves and in wrist pin bearings, also in other hot spots in the engine, but those were the places that caused my pistons to melt, and scored the cylinder bores (fragged rings) and caused broken rods where the rods seized on the wrist pins. It smelled wonderful for a couple of weeks, though... [Smile]
 
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151
Location
so california
Hello All: Back in the "old days" I used to get a free ride to SCCA races by being a low-level pit crew member for an E-type Jag racing effort. My job was to get under the car after each race (this is before legal liability/child work rules) and dump the engine & gearbox oils while HOT (not warm, but as soon as possible before engine cool-down.) The car used the old Castrol R (bean oil) in the engine and gearbox and carried Castrol sponsorship- hence the endless supply of fresh cans. I recall that the oil back in the mid 60's was over $1.50 per quart. Has anyone ever found any comparison on this stuff vs. modern oils? I know that lots of the Formula B/C guys with expensive motors used it & I've always wondered just how good it was. TIA Bill. p.s. Since most of us then drove "beater" $200 British sportscars, we used to put a few tablespoons into our gas tanks just for the exhaust smell!
 
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7,430
Location
beaver land EH?
The name Castrol came from castor oil which has good properties being motor/engine lubricant but short duty life. Back in the pre-SA days where most mineral based dino motor oils were just straight cracked virgin based motor oil (Pennzoil rules then), castor oil worked out to be a good, sensible choice. I believe back in those days, Castrol makes R-3 (correct me if I'm wrong) which is castor oil based for race cars. Again, it only comes with very short service life. With a lot of robust, multi-vis motor oil available these days (Gp2+,3, 4, PAO, etc.),with excellent service duty and long service life, I simply cannot see why/how someone would go back to castor oil. But then again, castor oil mix for 2-stroke RC engine gives off a distinctively "sweet" smell...(*grin*)
 
Messages
76
Location
Southern Florida
quote:
Originally posted by Ray H: Castor oil is superb in high temperature applications but has one nasty habit - its molecular structure changes after being heated and it congeals to an unpumpable, undrainable gell at cooldown. If it's allowed to cool to ambient temperature in the device, that device has to be disassembled and the goop literally dug out. Castor oil was used for WW-I aircraft engines as well as early race cars. In addition to prompt engine drains for those pilots fortunate enough to make it back from a mission, the lack of valve covers meant the pilots were constantly exposed to castor oil mist. Those brightly colored scarves the pilots wore weren't merely for jaunty show - they protected the pilots' mouths and nostrils from excessive exposure to the oil mist. Even at that, the pilots still ended up with strong urges by the time they landed. Latrines were thoughtfully provided near the end of the taxiways for those really regular guys. In that era there were old pilots and there were bold pilots. There were no constipated pilots, though.
Interesting story/facts Ray....Thanks!
 
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8,711
Location
Nothern USA
Dug out a booklet let over from my days as a paint chemist. Castor oil, 87% ricinoleic acid, 7% oleic acid, 5% linoleic acid, 2% palmitic acid, and 1% steric acid. They are all present as mixed esters of glycerin. An ester is formed by reacting an acid with a hydroxyl. The ricinoleic acid does not ''dry'' (polymerize) like most vegetable oils. I see 2 routes to the gelling. In the heat of the engine, the hydroxyl could be driven off along with a hydrogen leaving behind dehydrated castor oil, a fine drying oil. There could also be ester interchange, where the linkage to the glycerin breaks down and the acid group on one forms an ester with the hydroxyl. The acid could also be a linolic one that bonded to a linolic on another molecule. Most vegtable oils will polymerize when heated in the presence of oxygen without a stout dose of antioxidants. I prefer less reactive products in my engines. Esters are OK as long as you don't mix different types.
 
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681
Location
TX
Aren't oleic acid and linoleic acid used as friction reducers? I remember the wonderful smell from my friend's brother's go-kart when he used castrol. I also remember the gum in the gas tank and carburetor after it sat over the winter.
 
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8,711
Location
Nothern USA
''Aren't oleic acid and linoleic acid used as friction reducers?'' In small quantities, they aren't going to cause big problems. Of course, we change oil because the additives are worn out and sludge is starting to form.
 
Messages
151
Location
so california
Great comments...glad to see I'm not the only one who remembers "R" and enjoyed breathing the exhaust fumes it created. Re: My original post; putting aside the short effective life of this oil, would anyone care to guess how this would compare to a modern racing (syn or dino)? Has anyone ever seen any period test data comparing it to the then state of the art dino oils? Finally, does anyone (Torco, etc.) still make this stuff? Seems that an "exhaust aromatic enhancer" would be just the thing for those expensive VARA classics racing today! Bill.
 
Messages
151
Location
so california
beanoil: Thanks for that link...I had no idea it was still being made. This stuff must have merit if it can still exist alongside the latest synthetics. Bill.
 
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