I was examining one of my /5 restoration projects and snapped this pic of its dipstick. I'm assuming this in one of those ISO oil coolers? I didn't find much info with an online search, so figured I'd tap the collective wisdom here. I read it was designed by a NASA engineer and the measuring tube houses a liquid that transfers heat from the engine oil to the top cooling rings. Obviously, it performs its task as an oil measuring stick with finesse.... but what about the scientific cooling part? Anyone have one? <img src="http://farm6.static.flickr.com/5095/5423936306_2af5124f74_b.jpg" width="1024" height="768" alt="IMG_3660" /> <img src="http://farm6.static.flickr.com/5258/5423335811_589fd10b0a_b.jpg" width="1024" height="768" alt="IMG_3668" />
Wowza! I can't wait to hear scientific analysis of that beauty. I can't believe that it has any significant effect on oil temp...but I'm no scientist. Besides, if it did, wouldn't BMW have used that instead of installing inelegant, cludgy and expensive oil coolers? But again, I'm no scientist. I'm just someone who extrapolates based on bad information. Story of my life.
The threaded connection is effectively an insulator, so any cooling effects are negligible. Hot below, cool above... kinda like the stock dipstick.
I wouldn't assume any vast cooling efficiency with this, it's just so damn oddÂ….. or maybe over-engineered for a dipstick. I tell you one thing, it's a hell of a lot easier to unscrew from the case than the stock stick!
Nuh-uhh.... It's a heat-pipe cooler, and the heat source is primarily the hot oil mist flying around in the cases on the way from the bearings to the sump. The cooler design, despite its' detractors' not knowing any better, can actually move a lot of heat when done right. If you've ever oveclocked the cpu on a computer, the upgraded cooling solution that kept the hotter processor happy was probably a heat-pipe cooler. They're not as good at rejecting BTUs as a dedicated conventional cooler, but better than nada, and w/o the plumbing needed for a conventional cooler. More tip-over proof too.
I understand what you're saying and I still believe that the threaded connection accounts for only negligible internal heat dissipation. The entire heat sink is trapped (in contact with the heat source). Thus, I would think that it might be slightly cooler to the touch (thus easier to remove when the engine is at operating temperature) than the stock one, but it would not provide noticeable cooling effects anywhere past the threads.
I don't know whether they work or not but those are pretty rare Airhead accessories these days. Actually, my bet is that they do work but are simply not effective enough to cool the engine to any appreciable degree. I had one on my 1970 R75 and if I could get one for my R100, I'd have one. I just think they're kool and you never see em anymore. PS CDD: The threaded part pf the cooler has nothing to do with whether if cools or not. The stem contains a metallic or liquid cooling material (I don't remember which anymore.) that conveys the heat to the heat sink. They are reputed to work but I doubt that they'd replace a real oil cooler.
FWIW, I guess I'd be interested in the science as to whether this device cools a 1970 - 1995 BMW airhead in any meaningful way. There's no doubt that the concept is sound and remarkably effective in some situations. It just seems that the heat dissipation capacity of this dipstick is minimal relative to the heat created by an airhead. I'd love to see oil temp gauges on two similar bikes traveling down the road side-by-side, one with this marvel and one w/out. And then the same gauges on the same bikes traveling down the same road after the dipsticks have been swapped. Just curious cause I'd love to rid my GS of the Rube Goldberg oil cooling contraption that it has. Again, I'm certain that it has a greater cooling effect than a stock dipstick. I just wonder what kind of device is needed to measure that effect.
Read the linkie, and all wll become clear. Or not. your is the choosing. This one, if it is still holding its' vacuum, probably uses methanol as the heat transfer fluid.
I read the linkie. Much appreciated. But despite all the talk about space craft, CPUs, nuclear power cells, pipelines over permafrost, etc. I didn't see any mention of this type of device being used to cool an airhead. I'm convinced it works, but I'd just be interested in how much it cools the oil in an airhead during everyday use.
I'm sure it moves some heat. Whether it moves enough heat to have a meaningful effect on your oil temp is another thing. One thing I AM relatively certain of is that it DOES move enough heat to make the heat sink on top hotter than hell and thus makes it a sonofabitch to check your oil bare handed.
All you have to do is calculate its area in relation to the total engine casing area. It will give you a good idea of how meaningless its cooling contribution is!
I'd have to guess that the rarity of this item attests to it's relative ineffectiveness in this application. If it were a better mousetrap everyone would have one.......:huh It being a 'period' accessory it will have some attraction.
I had bought it on ebay about 10 years ago. I thought it was so cool that NASA had designed my dipstick....!!! But it did look pretty neat next to my very clean engine block and shiny heads... <a href="https://hardwaregrrl.smugmug.com/Other/misc/16038929_btsAe#1210871424_xE9Yk-A-LB" title=""><img src="https://hardwaregrrl.smugmug.com/Other/misc/IMG1273/1210871424_xE9Yk-M.jpg" title="" alt=""></a>
All the shiny does look nice. But, you would get more heat transfer than the NASA dipstick can provide just by sandblasting all the surfaces and leaving them rough.
When I saw the title to this thread I thought it was gonna be another one about Asian built BMWs on eBay.
FLIR PICTURES NOW!!!! or you're all wrong. That's the cadmium control rod to regulate the rate of fission.
Yeah... Kinda been the mood here lately. Yup, those were my thoughts exactly. Aside from it's cooling ambiguity, it makes for a conversation piece. I just hope this methanol filled 'potato masher' doesn't spring a leak in the case.
