| Author | Message | ||
     Blake |
Me too. My clumsy explanation of an "insulating boundary layer" was the result of dredging up information logged away 20 years ago with an imperfect information system (my memory). The layer I speak of is the layer of fluid that actually contacts the inside surface of any container that holds it. That would be incorrect. The boundary layer includes the film of which you speak, but it also includes adjacent “layers” out to a point where the fluid velocity becomes “significant” with respect to the free stream velocity. I still have my text from the graduate fluid mechanics class I took. ![:]](http://www.badweatherbikers.com/buell/clipart/proud.gif) This is why, all else being equal, the effective boundary layer for turbulent flow is significantly less than that for laminar flow **Since the velocity of the fluid layer adjacent to [a] wall is zero, the heat transfer between the surface and [the] fluid layer must be by conduction alone.** That is 100% correct. Would that principle also apply to the inner surfaces of any fluid carrying vessel, like a heat exchanger aka “oil cooler”, right? This layer of fluid that exist in any container that holds oil can never be turbulent if the velocity is zero. Likewise for an oild cooler. Be carefule, turbulence is a macro geometric property of fluid flow. It is not applicable to a molecularly thin film. Turbulence affects the thickness of a boundary layer; by definition a boundary layer is never turbulent. This is what I meant by an "insulating layer", the conduction at the interface. Like I asked before… Is hot motor oil more insulatve or more conductive… more like water, or more like styrofoam. I'd like to get straight to the point and counter a specific statement you posted. This statement pretty much sums up the information I disagreed with in earlier posts. "Suppose the oil cooler's cooling passages have a capacity of 4 onces (1/8th quart) an internal surface area of 20 square inches and an effective external surface area of 40 square inches. If we assume that we have a 3 quart total oil capacity for the engine/reservoir/filter, the oil cooler represents 1/24th of the total oil system capacity. The equivalent surface area corresponding to the total capacity would be 480 square inches (24 times 20 sq inches). Comparitively, the oil tank would hold roughly 2.5 quarts (5/6 of the total oil system capacity) with an interior and exterior surace area roughly equivalent at around 300 square inches (guesstimate) for an equivalent total capacity surface area of 360 square inches (6/5*300). That's not too far off from the total capacity equivalent volume of the oil cooler. In other words, with the addition of some fins and vigorous airflow, the cooling potential of an aluminum oil tank could be comparable to that of an oil cooler." This can not be true. You are only taking into account surface area for a sump vs. oil cooler and disregarding two important considerations: a) fluid velocity b) the ratio of inside surface area/fluid volume You are apparently assuming that the velocity/mixing within the oil tank is insufficient to support a high rate of heat transfer. That is a VERY big assumption. The outer surface of my aluminum oil tank gets quite hot. What does that indicate? I agree, there are factors which govern heat transfer that I did not include the above discussion, however if the velocity/mixing within the oil tank is sufficient to support a high rate of heat transfer, and I believe it is, then the only variables that matter are surface area. As my discussion shows, the oil tank when viewed versus the total single pass system cooling capacity of the oil cooler is a bit less than the oil cooler. But to say the oil tank could not be an effective oil cooler is another thing entirely. It easily could be. I’ve already described the reasons why oil tanks are NOT used as oil coolers. In forced convection, fluid velocity has a direct bearing on heat transfer. **The temperature gradient at the wall depends on the flow field, with higher velocities being able to produce larger temperature gradients and higher rates of heat transfer. That is correct of course. Do you know the relationship between the temperature gradient and fluid velocity? Is it linear, or is there a diminishing rate of return as velocity increases? The flow in the small passages of an oil-cooler are much higher than the flow of oil circulating through an oil storage tank. The rate of heat transfer (even if surface areas are equal) is much higher in an oil-cooler based on just this one premise. Remember, we're talking about velocity here and not volume. How might the time that the fluid is exposed to the temperature gradient affect total heat transfer? I didn't say more heat transfer, I said more efficient heat transfer. No one is arguing that an oil tank is as efficient in cooling oil as an oil cooler. The oil cooler is tiny by comparison, obviously much more efficient. You just made my point. The tank is not efficient, but it could, with the addition of airflow and fins become an effective oil cooler. The reasons that oil tanks are not used as oil coolers were described previously (lack of control, always on no matter the ambient or oil temperature). The conduction taking place at the interface between the fluid and the inside surface of the container places a limit on the heat that can be transferred from a large volume of oil regardless of the surface area on the outside Not necessarily, you are neglecting the time variable. There are examples using free convection that are simple sumps of oil with cooling fins though; we see them every day on top of poles that carry electrical equipment. These are applications where long term maintenance is troublesome and not financially viable. I disagree that, "a 3 quart aluminum oil reservoir with fins that are exposed to ambient airflow could shed comparable amounts of heat as a little 4 once oil cooler". Please realize I never said you were wrong; fins on a sump will offer some benefit, just not nearly as much as you would think. If the surface of an oil tank becomes much hotter than ambient air, fins are of great benefit in helping to cool the tank, which in turn cools the oil. You may be underestimating the effects of the mixing, sloshing and oil jet action within the oil tank. The reason I raised the issue was that I disagreed strongly with your assertion that oil tanks do not have fins because they are not effective in helping to cool the oil. The reason most oil reservoirs don’t have fins is that such uncontrolled cooling is highly undesirable. Fins would definitely aid significantly in transferring heat from an aluminum oil reservoir. | ||
| Djkaplan |
Blake, I appreciate the response. "This is why, all else being equal, the effective boundary layer for turbulent flow is significantly less than that for laminar flow." Not sure why you think what I said was incorrect. I never compared boundary layers in terms of laminar and turbulent flow. When I get some time, I'll crunch some numbers (Jeez, I wanted to avoid this) if only to convince myself I am right (or wrong!). I still think there's going to be a more significant temperature difference in 4 oz oil-cooler than a large sump with fins. Only you could make me go back and do this on my own time (for fun?). Oh, the wonders of the BadWeb... | ||
| Blake |
DJ, I'll be interested to see how you will characterize the flow/circulation/sloshing in the oil tank. Before attempting that, you might first look at just the properties and quantities of interest... conductivity of hot engine oil, conductivity of aluminum, the amount of heat given up by 3 quarts of oil in going from 220oF to 180oF. Then you can ascertain the delta air temperature at ambient temperature (50oF to 90oF) and some reasonable flow rate (60 mph?) that would be required to accept that amount of heat. Don't forget radiation from the tank, from the oil cooler the radiative losses are probably small enough to neglect. Sounds like fun. It's about time someone else cracked a textbook around here.  | ||
| Ara |
Reep, what do you safety wire the filter TO? | ||
| Reepicheep |
I put a cable tie around the base of the heim joint right beside it, and left the loose tail sticking out. I then use a big hose clamp (home store, not auto parts store) around the filter and over the tail of the cable tie. It could turn a quarter turn or so, but thats it. I will be happy to post a pic if anyone wants one. This was a quick kludge to solve an immediate problem (*cough* in the lot of the auto parts store at the end of a trail of oily right boot prints *cough*). I might work out something prettier after the next oil change, I was thinking a strap that goes all around the back and hits the big hose clamp in two places, but I have not looked closely to see where it would fit. | ||
| Henrik |
Ara/ Reepicheep; I used the large hose clamp as well, but used safety wire to secure it - and right now I forget to what. With the snail part of the clamp facing down I threaded the safety wire through an opening in the snail and secured it on the right side of the bike. That way the filter is prevented from spinning counter clockwise (loosening). I do replace the safety wire occasionally, but it is possible to loosen the clamp and remove the filter without cutting the wire. Just leave the clamp/wire attached, slip the new filter into the clamp and tighten. Henrik | ||
| Ara |
Reep & Henrik - Thanks, guys. Couple of good ideas there. I've got a Billet Cool spin-on oil cooler installed and next oil change I'm going to be using the Mobile 1 equivalent of the FL-300, which is the shorter but full-diameter version of the FL-1A. I'm definitely going to safety wire it because I've got TWO things that can loosen and leak. Appreciate your suggestions greatly. Russ | ||
| Bomber |
I've seen some folks use clamps the look like jumbo versions of the one holding the shock resevoir to the front muffler mount . . . . the bolt coing through the clamp can be positioned against the engine cases so the filter can rotate . . . . clean, easy, no safety wire required | ||
| Rick_A |
Well, I got my cooler setup on. I ended up using a vertical mount Sportster oil cooler from Lockhart with a Jagg bypass valve. It clears my steering damper and I had to run about 4.5' of extra oil line to keep the routing looking clean. It added almost 1/2 quart to my oil capacity. Looks awesome...and the weather hasn't gotten hot enough to see a real big difference yet. | ||
| Buellistic |
Rick_A: Have you went to "SYC3" oil yet????? Going to put a "COOLING FAN KIT" on????? In buelling LaFayette | ||
| Hoser |
Youz Guys discussing the oil filter safety wire thing , do this................................  | ||
| Reepicheep |
Very cool solution Hoser. I will keep my eyes open for one of those nice clamps. Does it chew up your case at all where the bolt rests against it? Looks like it might be a little annoying to get a wrench in there as well, though I suppose you could just leave yourself a quarter turn of tightening margin and just tighten a little, remove the clamp, then remove the filter. Thanks for the post, I think I will try that. | ||
| Road_thing |
That does look like a neat way to secure the filter positively.  You could probably get a rubber or plastic cap for the end of the bolt to keep from marring your cases, although I've personally never seen a filter back off, and I doubt you'd notice any scratches in that particular location, anyway! r-t | ||
| Lake_bueller |
Pop goes the oil cap (sort of).... I've found some info on popping oil caps in the archives. However, there doesn't seem to be any real fixes mentioned. Most people recommend removing the cap when you start the bike. It seems like there should be a better solution. Now for a little background.... I just got the bike back on the road after a long winter of misc. projects. One of which was replacing the rocker gaskets with the metal upgrades. I replaced the filter and added oil to the proper level. For the first two days, no problems. Day 3...the bike is billowing blue smoke from the exhaust. My first thought is that I really F'd things up somewhere. Then the smoke disappated. I went for a brief ride and everything seemed fine. Day 4...the bike is billowing smoke again. I decide to again check the oil level. BTW...I have a Banke cap (you know, the screw-on type). When I removed the cap, it popped like a cork. Within seconds, oil is pouring out of the reserve tank. It settled but at a below normal operating levels. Any suggestions?!?!?!? Sorry about the lengthy post. I just wanted to get the all the background info out in the open. Thanks, Dennis | ||
| Ara |
I think he's already got a rubber cap on the bolt. Hoser, where'd you get the clamp? | ||
| Mikej |
Dennis, Check your primary fluid level before you do anything else, Also ensure the vent lines are free and clear of obstructions. Then redrain the engine oil and measure how much comes out. You could have had oil settle down in the engine and it might be coupled with a stuck checkball letting the oil drain right back down. For the blue smoke out the exhaust, is it actually coming out of the end of the exhaust pipe outlet? Could it be from a stuck ring? Remove your spark plugs and crank the engine over and see if anything blows out the hole (like oil). If the oil has settled down in the enging, and is doing so each time you shut it down, this may or may not be the cause of the bus-flume of smoke out the tailpipe. I'll let the engine experts chime in on this one at this point. | ||
| Buellistic |
If you change the oil and filter(HDI) the system only holds 2 1/2 quarts... You take it out for a ride to get the engine to operating temperature... With the engine running you check the oil... Mark the dip stick as this will be where the oil should be with a fresh filter and oil... From then on always check your oil after you have come in from a days ride... Now if you have trouble getting this right you can put a "PCV VALVE" set up in the timing hole and if you put too much oil in it will "PUKE" it out the "PCV" hose until the engine gets to the correct oil level... In buelling LaFayette | ||
| Buellistic |
Now before someone says my transmission vent hose is blowing out oil... If you put to much in the system or up north run too heavy a oil when it gets cold... The BUELL oil pumps it back a little faster than it sucks(with the help of gravity) out... On a cold start with 20W50 in the cold mornings with the seat off it will blow a stock filler cap about 10' in the air with a pow in N.C. in October... Too much oil has to go some where: into the head breather hoses into the air cleaner(if you sitll have the stock factory set up) and onto your pants leg,it will go past the crank pin seal tranmission side and blow out the trans vent hose, in some cases out your cluthh cable getting your clutch hand oily, not for getting weeping gaskets... In buelling LaFayette | ||
| Steveford |
Does anyone know what the viscosity rating of Sport Trans and Type E fork fluid really is? | ||
| Buellistic |
Steveford: That's not important, but what is, is that all "BUELLS" should be running "SCREAMIN'EAGLE SYC3 in the engine and transmission... The next important thing is you should go to SCREAMIN'EAGLE fork oil P/N99881-87... If that is not satisfactory go to race kit fork springs... In buelling LaFayette | ||
| Blake |
Lake, What Buellistic said. Sounds like you have too much oil in your engine. Only check/change oil after the engine is warm, otherwise you risk leaving a significant amount of oil inside the crankcase. Steveford, I sure don't. But HD now recommends their 20W50 synthetic oil for the tranny and Racetech recommends 5W oil for the forks. | ||
| Hoser |
Ara: The clamp can be sourced at an industrial supply store , one that sells truck / heavy equipment parts. These clamps are used for a variety of things like large radiator hoses , turbo / air cleaner ducting etc on trucks , buses , earth moving equipment , available in a range of sizes too. Slip a rubber plug ( vacuum port plug ) over the stud to prevent scuffing up the crankcase. | ||
| Al_lighton |
NAPA sells em. They're called T-Bolt clamps. If the counter guy doesn't know this, he has a catalog of a bunch of different kinds of radiator clamps, and they're in that. There's a bunch of manufacturers of them (Clampco,5-Star, are two). Its a nice sano solution. I've never had one come loose without the clamp, but all it takes is once to ruin your day. | ||
| Reepicheep |
Al. I have. It did. Actually, it turned out fine. I was wearing full gear, and noticed a big trail of smoke on my mirror checks while aggressively riding some twisties. Once I made sure that it was not the car in front of me, I quickly found a place to pull over. Before I got there, It felt like my rear brake toe peg had unthreaded and was loose (it was solid, but soaked with oil). Then I noticed that I had no rear brakes whatsoever. It then started creeping into my head that perhaps I should be stopping and turning VERY gingerly. I was soaked in oil on my right leg from toe to knee. Never even felt it, had pretty good gear on, boots and Cordura armored riding pants. Had I been in jeans, it probably would have at the least hurt, and maybe burned me, who knows. Because of the hugger fender and the airflow over the bike, I think when this happens, you get "one free stop in a more or less straight line". The tire was wet all along both sides, but the middle was still dry when I came to a stop. Once stopped, stuff just went everywhere and the tire was soaked, as well as everything else from the oil filter back. Major panic for a moment sitting on the side of the road seeing oil EVERYWHERE. And this was right after some major work on the cam side and oil pump, so I though I really screwed something up this time. Once I saw the mostly unthreaded oil filter hanging there, you never saw a guy so happy to be broken down on the side of the road "> There was enough oil left in the system to keep pressure up and let me limp to the nearest auto parts store for more full synthetic 20w50. I now keep an extra quart with me on the bike, and tie down that oil filter. Note this was the big ford FL1A, I never had the problem with the stock part. Thanks for the NAPA tip, I will go get one. (Message edited by reepicheep on May 07, 2003) | ||
| Buellistic |
Bill: Been running a FORD Motorcraft FL-1A for years... That has never happend to me????????????????????? Maybe that is why "i" always safty wire no matter what oil filter "i" have ever installed... Remember O'TOOLs LAW: "MURPHY WAS AN OPTIMIST"... In buelling LaFayette | ||
| Hoser |
It's happened to me too , when I first started using the long dyna filters , during an evening ride heading into the sun , luckily I spotted the oil pressure light glowing and noticed the rear wheel a bit squirely when pulling off to the side of the road. The filter was backed off a few turns and the gasket was dangling , swaying in the breeze. I screwed the filter back on checked the oil level , and was able to proceed to the next town where the oil was topped up and a car wash tidied up the big mess. | ||
| Kinger |
I have been doing some routine maintenance stuff on my bike on and off for the last week or so. While looking over the service chart, I noticed that the service manual calls for changing the engine oil every 5,000 miles. Is this the interval most of you use? Just curious. Thanks. | ||
| Buellistic |
Kinger: Have a 97S3T and just as of last ride turned over 60159.4 miles ... The "TOP-END" has never been off...Have used 20W50 HDI for first 60K changing ever2K... Have went to SCREAMN"EAGLE SYC3 20W50 and now going for another 60K(will change every 3K now)... In buelling LaFayette | ||
| Sarodude |
Synth Oil Mist Q... I've read a couple of posts around here indicating that running synthetic oil reduces the amount of oil mist. Any clues as to why? -Saro | ||
| Buellistic |
Sarodude: Maybe one of the "OIL ENGINERS" can tell us ALL... Have never heard that one before... Hear something new every day... In buelling LaFayette |
