| Author | Message | ||
     Blake |
Steve, Careful with any conclusions from the above. Notsip provided the 35 FT*LB make-up torque for the cylinder studs. Interestingly the service manual calls for tightening the studs in stages to 12-14 FT*LBs followed by a final 1/4 (90o) additional turn of the nut/screw. The turn-of-the-nut method for achieving bolt preload IS widely recongnized by many structural codes as an approved method for installation of high strength bolts in slip-critical connections. Again, uncalibrated torque is not. The preload analysis/estimate using the manual's specified tightening procedure may reveal significantly different results. Unfortunately I do not have the information (stud/screw geometry, grip length and thread specification) required to perform that estimate. It is slightly more involved. One would estimate the preload due to torque then add to that the preload due to 1/4 turn worth of additional elongation of the stud/screw assembly... P=(1/4)/(n)*(K) where n is the number of threads per inch, and K is the axial stiffness of the stud screw assembly calculated using the properties of each unique cross section comprising the effective grip length of stud/screw. K is basically the reciprocal of the sum of reciprocals of each individual section's stiffness. In mathematical terms [Sn 1 (Li/AiEi)]-1 where A is the effective cross sectional area, E is the material's modulus of elasticity (Young's modulus) and L is the length of each distinct portion of the stud/screw assembly. Anyway, maybe we can get some accurate data and have some more fun with numbers. | ||
| Mikej |
 So, was I right or wrong in my assumption about why my bike venting is variable? | ||
| Notsip |
Blake, The 35 ft/lbs. was achieved as a approx. torque setting by torqueing the head screws to 14 ft/lbs and then rotating 1/4 turn. Checked with a torque wrench it came to 35 ft/lbs +/- 1 ft/lb. Anyways what are you trying to figure out and why? Save your energy, I have something else coming that will occupy your talent for a while. | ||
| Mikej |
I think I'll just assume I was sort of right and sort of wrong and sleep well tonight. Besides, I'm wearing another hole in my head scratching it with my finger like that. ouch. | ||
| Roadrunr |
NOTSIP,WHAT ABOUT THE SPEWAGE! What does suspension have to do with spewage? | ||
| Blake |
Notsip, "On the mounting of the engine Blake speaks about the way it should work. And I agree mostly with what he says. But in real life it doesn't work as well as we think it should." Well, upon further investigation I find that I was wrong in saying that the action of the upper/center tiebar bracket is inconsequential to this discussion. It, surprisingly to me, does indeed rigidly connect the cylinder heads to each other. That would tend to create a tension pulling the cylinder heads together as the engine heats up. The effect of that rigid connection during thermal expansion of the cylinders may or may not be significant. The placement of the bracket's bolted connections to the heads appears to be the best possible choice to avoid excessive distortion to the cylinders. The added rigidity may provide significant benefits. It certainly makes a world of difference in the overall structural rigidity of the engine. "There are to many other flexing factors that comes into play. I didn't mention them because I didn't want Blake to waste his time in figuring them out because what it is designed to do doesn't always work as designed. Save your energy for later." Let me get this straight Notsip... You don't want me to waste my time figuring out something that captures my interest and for which I am eminently qualified to address, but you feel fine asking disingenuously for my help in analyzing a problem for which you believe you have the irrefutable answer? I'd appreciate very much your dropping what I see as a very patronizing attitude. As to a design not working as intended by the designers... You may have the impression that the expected fruition of engineering design is functional perfection. That in fact is almost never true. There are almost ALWAYS agonizing compromises that must be made in the process of any complex design. Structural materials are rarely perfect. Geometry is never perfect; manufacturing tolerances are many an engineer's unrelenting nemesis. Structural restraints are rarely able to be perfectly implemented. Quality of vendor parts and manufacturing processes can vary. Then you get to operational scenarios... should a streetbike be designed to endure racing conditions without a degraded operational life? Will engines be faithfully/carefully broken-in as required? Will customers seek to alter the stock machine to augment performance or looks? Will maintenance be performed as required? Will operational guidelines (not dropping clutch on a downshift) be followed? It's awfully damn easy for someone to pontificate that "theory is theory I deal with the real world" until that person tries to sit his ass down and actually design an economically viable, manufacturable, complex machine. As an example, consider that we can easily design an upper/middle tiebar support mechanism that rigidly supports the engine laterally but allows the two cylinder heads to expand unhindered away from each other. If indeed that is desirable, it is easily accomplished. It would add cost, weight, and complexity. A good designer must weigh all factors against any potential imperfection in design and its effect on function. The crankcase could be built from steel for more rigidity. It would add unacceptable weight. For a sport bike that is already not anywhere near the lightest, is fabricating the cylinders from solid cast iron really a great idea? These are not cruisers. What real benefits would it bring versus the existing design? Designers must consider the big picture, the overall system (the overall performance of the bike). "As for the cylinder studs, the number that I used was figured using the actual cylinder stud supplied by H-D." Are you joking? It was "figured"? Are you saying that your "I already know what it is" preload is a mere estimate? It was not a result of direct measurement? Cause that is the ONLY way to be certain of the actual preload; even then there will be significant uncertainties in repeatability. "I know that the numbers that Blake and I have are a little different, but if you want the exact clamping pressure take a H-D stud and have it analized then take the results from that and then refigure your loads. You will see why there is a difference." There is NO analysis method I know that will yield trustworthy let alone "exact" predictions of bolt tension versus torque. To be accurately known, preload must be measured; otherwise it is simply an estimate. Even when measured there are inaccuracies that must be addressed. "In going with your scenerio with combustion pressure, and this is different depending on what compression is being used, no there is not much margin there. That is why it is imparative that the engine be thoroughly warmed up before applying any loads to it." I was hoping you would tell us what the actual peak combustion pressure is for a stock Buell engine. Please do if you know what it is. "Blake is correct, the frictional horsepower loss is different at every rpm." My point was that at 6,000 rpm, power lost to friction will vary with throttle position (power output). I agree of course that it would also vary with engine speed. "The only cylinder that we have found that will withstand all of the rigors that it is put through is the Axtell Cast Iron Cylinder because of it durable strength." Please describe in detail the specific testing scenarios to which each cylinder was subjected. Without that information, it is difficult to draw any meaningful conclusions from your statement. "Yes it does have some drawbacks but I look at the overall picture." Really? Seems to me you are focused quite narrowly on only the cylinders. Why don't you also propose the benefits of fabricating the pistons and crankcase from cast iron or steel? "It maintain's it's concentricity better than anything else which gives you more consistant horsepower as heat develops in the engine." You may be right, but if you have evidence to support that claim, maybe you could share it? "Also keeps blow-by at a minimum." Again, evidence supporting that claim would be nice. "My thought process is this. Less weight equal less stability and concentricity which reduces consistant horsepower output, reliability and increases blow-by. More weight equals more stability and concintricity which produces consistant horsepower output, reduces blow-by and increases reliability. This is not a hard one to figure out. Your opinions are interesting, some make sense, some don't, some are wrong. What bothers me is that you seem to present your opinions and assumptions as fact along with a bunch of very vague generalities. Though you claimed to possess it, I'm not seeing anything resembling actual evidence in support of your assertions. Maybe you have it all in your pocket waiting to include in the next stage of your discussion. I hope so. To be honest I'm bothered by your glib confidence and persona of self assured expertise, when in fact you started out talking about the supposed detrimental effects of rear shock mount loading and engine braking on the cylinders' geometric integrity and rate of wear. Those were not valid theories. Now you offer that... "My thought process is this. Less weight equal less stability and concentricity which reduces consistant horsepower output, reliability and increases blow-by. More weight equals more stability and concintricity which produces consistant horsepower output, reduces blow-by and increases reliability. This is not a hard one to figure out." That is an interesting "thought process", but it falls short of being convincing evidence. In light of the fact that NO modern motorcycle engines that I know of come fitted with cast iron cylinders, you might want to rethink that position. Are you aware of the effects that added mass has on structural resonance? I anxiously look forward to hearing more about your observations on the breather pukage issue. "...your analogy on the swing arm theory is flawed and you may want to rethink it." What "theory" are you talking about? I don't recall offering any kind of "analogy" wrt the swing arm. If something I've stated is technically inaccurate, please identify it and offer a correction/clarification. Doing so will allow the discussion to proceed much more efficiently and smoothly. "I am not an engineer so therfore I can only state what past experiences has taught us." I don't follow your meaning there. You certainly don't need to perform any engineering analysis to present pertinent data and/or observations. I'd caution that what many consider as valid conclusions based upon experience (observations) are often unable to withstand the rigors of critical review. For instance, I install and test two sets of cylinders according to the same procedures. Set "A" outperforms set "B" by a wide margin. One could easily conclude that set "A" represents a superior component. Oops, further investigation reveals that set "B" should have been torqued differently, required different compression rings for optimum performance, as well as a different piston to cylinder clearance. Then of course there is the problem of statistical validity. With a sample size of only one, it is very difficult if impossible to draw any meaningful conclusions from test results. "Again things don't always work the way that they are designed and intended to." True. However, the vast majority of engineered and tested "things" do work the way that they were intended. "This is probably one of those situations." Just to clarify... What exactly about the Buell are you contending does not work as well as intended? I assume you mean the integrity of the ring/cylinder seal? Blake | ||
| Steveshakeshaft |
Interesting points all round. For those seriously interested in learning about the behaviour of bolted joints you need to track down a book by JH Bickford, "Introduction to the design and behaviour of bolted joints", publisher, Marcel Dekker. A good practical bias book well worth a read. But in a nutshell, Blake's right. | ||
| Bomber |
MikeJ . . .your spewage is variable due to the varying nature of sins commited in a previous life, and, therefor, your variable Karma . . . given your life this time around the wheel, you should be able to accurately predict spewage rates during your next incarnation . . . . if you life mirrors your B'Trax times, your spewage will be of unknow amounts, but constant. Hope this helps. | ||
| Mikej |
evah ot mees I ,tiaw ,mmmh ,rebomB sknahT .toohs ,emit siht sdrawkcab tuo emoc JekiM | ||
| Court |
>>>you should be able to accurately predict
| ||
| Bomber |
Mike . . .simply cross your arms in front of you when typing . . .this should clear the trouble you are experiencing | ||
| Mikej |
Ah, but a predilection is an entirely different matter.  | ||
| Mikej |
How do you think I typed that in. Sat backwards too. | ||
| Court |
>>>Ah, but a predilection is an entirely different matter Call me when you reach "pre-dereliction" | ||
| Bomber |
too late, Court . . .Mike passed that stage long ago | ||
| Court |
>>>too late, Court . . .Mike passed that stage long ago I think I felt the disturbance in the force... | ||
| Bomber |
THAT, sir, was the remains of a re-fried bean encrusted kringle | ||
| Mikej |
http://www.m-w.com/cgi-bin/dictionary One entry found for dereliction. Main Entry: der·e·lic·tion Pronunciation: "der-&-'lik-sh&n Function: noun Date: 1597 1 a : an intentional abandonment b : the state of being abandoned 2 : a recession of water leaving permanently dry land 3 a : intentional or conscious neglect : DELINQUENCY <dereliction of duty> b : FAULT, SHORTCOMING ================ I do believe I've done been insulted, insinuatingly so, indubiously.  Okay, back on track, Catch Cans, why and wherefore?  | ||
| Mikej |
Cube alert, cubical alert, to the doors, ruuuuuuuuuuuuuun  | ||
| Rick_A |
I've never had a spewage problem with my Buell...but...I did have an oil consumption problem on a long trip. I was using H-D dino oil instead of my usual synthetic and used about 1/4 quart every 500 miles. With synth I may add a few oz to top it off every 1000 miles. | ||
| Mikej |
Rick, Where are your rocker breathers vented to? Open air or into the intake or into a catch can? | ||
| Notsip |
There are a couple of things that I didn't cover in the last post. I didn't get into the amount of heat that is seen in the cylinder at running temperature. We done a test recently and found that the cylinders do not operate at the same temperatures. We found the following. Front cylinder temperatures were: Thrust Side: Top 365 deg., Middle 380 deg. and Bottom 325 deg. Non-Thrust Side: Top 185 deg., Middle 184 deg. and Bottom 182 deg. Rear cylinder temperatures were: Thrust Side: Top 197 deg. Middle 196 deg.and Bottom 191 deg. Non-Thrust Side: Top 440 deg., Middle 445 deg. and Bottom 431 deg. FYI piston scuffing begins at approx 465 deg. depending on material of piston Now add this radical temperature differences to the already stressed cylinders and it is almost impossible to keep the cylinder rings sealed because of the distortion of the cylinder. Now let's add in the powder coating that is applied to the cases, cylinders and cylinder heads. For every .012" of coating that is applied to the surface of each component it will reduce the cooling capabilities by approx. 40%. Now we are going to look at the motorcycle in riding trim. We have a front wheel, fender and forks blocking the air from reaching the engine. On the bottom of the engine you have a shock on one side, a muffler on the other side and with a air dam on some models. On the cam side of the engine you have a huge air box and a closely fit exhaust system. Now you get on the motorcycle and put your legs along side of the engine behind the air box. How is this engine supposed to get any air to cool it's self? With all of the stress, frictional heat and the inability to shed heat through the material beacuse of the coatings and lack of air supply it's no wonder there is a problem with blow-by and excessive crankcase pressures. Because of all of the problems and several more that hasn't been discussed, this is where your spewage is coming from. I'll start from the first post and breifly touch on each topic we discussed. Added stress applied to engine through the action of the suspension will add stress up through the cylinders and causing them to distort. Then you add in all of the friction created by the moving internal parts. Then add in all of the blocked air not getting to the engine to properly cool it. Then add on the coatings to the engine components. This causes a tremendous amount of heat build up in the engine, which then cause cylinder distortion and that causes blow-by and that causes excessive crankcase pressure. With what we have discussed it is very apparant that the engine has become a huge heat sink without any way to cool it's self properly. Now we will get to the spewage problem. I have seen where some of you speak of rocker boxes leaking. The problem that they are leaking is because of the excessive heat and the rubber gasket is failing. So if the rocker box gaskets are fialing that means that the umbrella valve are also failing. Without these working properly the excessive crankcase pressure that is created by the blow-by is going to go past the umbrella valve at a higher speed and is going to carry oil with it. THE FIX: 1) Replace the cylinders with Axtell cast iron cylinders that will not distort very much and you will cure your ring sealing problem and thus your crankcase pressure will drop way down and you won't have as much blow-by. 2) Reduce the amount of heat developed by the engine and increase the air flow to the engine. FYI: From this testing that we have performed we have developed the "COOL-SHOT" Piston Oil Squirter that will reduce the cylinder temperature by approx 225 deg. in the hottest spot. Thank you for your patients, we have finally reached some of the causes of spewage. I hope this has helped you with your spewage questions. | ||
| Mikej |
So, if I read that right, the heat in the cylinders is on the outside (front of the front, rear of the rear) of the "V", and the coolest parts of the cylinders are in the middle of the "V" below the intake. I would assume this heat differential is caused by the cooler intake air in the middle, and the exhaust port on the outside of the "V". Can I safely assume that on the VR/RR/XR editions of the engines that the main heat will remain on the exhaust side of the engine cylinders? Probably obvious, huh? Would running a dual-carb setup with a VR/RR/XR configuration rear cylinder help to keep the rear cylinder farther away from the scoring temperature potential? Are you basically saying we need either iron jugs or oil squirters or a new configuration to "cure" the spooge? The 40% reduction in cooling efficiency sounds a little suspect, didn't think paint was that much of a thermal barrier. Some, yes, but not 40% worth. Not saying your wrong, just sounds like too high of a number. I've worked with the design of cooling components in a steam environment and nothing got painted due to the critical nature of the needs. | ||
| Jprovo |
Notsip, Test conditions please, air speed, cylinder type, bike type compression ratio.... Did you measure the exterior on the interior temperature of the cylinders? The interior of the cylinders will be hotter than the exterior of the cylinders, so if the rear cylinder has an exterior temp of 440-445 F, then the rear cylinder temp will approach the 465 deg scuffing temp at the piston. The asymmetric temperature gradient will have a much larger effect on cylinder distortion than suspension stress any day of the week. The temperatures represent varying degrees of thermal expansion at the different temperatures, while the loads are on the magnitude of hundreds of pounds, distributed over the entire faying (gasket) surface of the cylinders. BTW, are your numbers for front and rear cylinders switched? I have always heard that the temperatures for the rear cylinder is lower than the front cylinder due to oil splash. Your powder coating cooling reduction of 40% sounds way out of line, can you cite your source data? What are stock Buell cylinders coated with? Why not use unfinished or chemfilmed aluminum cylinder (high thermal conductivity, roughly 175 W/m*K) than a powdercoated/high temp painted cast iron cylinder (low thermal conductivity, less than 75 W/m*K). I am an engineer, and I don't see any problems with Blake's FBD or load path diagram. I think that we can discount the Uniplanar mounting system as a cause of breather spewage, due to the number of Sportsters that experience spewage without the better chassis. BTW: thanks for the commercial  I think that your oil sprayers help, but they will help out a bike with higher cylinder temps (cast iron cylinder) more than a bike with lower cylinder temps (aluminum cylinder). I’d love to see the research that shows 200+ degree oil squirters reducing cylinder temp from 445 degrees to 220 degrees. My thought process is this. Less weight equal less stability and concentricity which reduces consistant horsepower output, reliability and increases blow-by. More weight equals more stability and concintricity which produces consistant horsepower output, reduces blow-by and increases reliability. This is not a hard one to figure out I have to laugh at this logic… Why not make the cylinders out of lead, it’s nice and heavy… Empirically, an aluminum shape with an asymmetric heat load will have a more uniform temperature gradient than a cast Iron shape with the same heat load. I have observed this in my college measurements class, and it agrees with my textbooks and calculations. Because of the better thermal conductivity of aluminum, and it’s more uniform temperature gradient, it will retain it concentricity/shape better than a cast iron cylinder. I won’t argue that ring blowby combined with poor head drainage is a source of spewage, but I don’t think that cast iron cylinders are the solution. Don’t get me wrong, I love my Ironhead Sportster, and cast Iron cylinders work well in high pressure applications (top fuel drag racing, turbocharging, etc.), but they really don’t work as well as aluminum cylinders do for modern street/roadracing applications. If cast iron cylinders worked better, HD would still be using them. HD had the technology and equipment to make cast iron cylinders until at least the mid 80’s, and the raw material is cheaper than aluminum. HD also tends to resist change, so the only reason for them to change to aluminum cylinders is that they work better. James | ||
| Blake |
Notsip, That's great data. Still need more information before it becomes really meaningful. I have questions. You apparently don't like to answer my questions. Please do so? Here are some more... 1. Is that data for aluminum or iron cylinders? 2. Do you have data for the other? What were the conditions under which the temperatures were produced? 3. What kind of performance did the engine produce on the dyno? 4. What comprised the engine, stock or high performance parts, bore, stroke...? 5. Was this a dyno test or on the road/track test? 6. What engine lubricant was used? Mike, the thrust side is the rear side of each cylinder. Here's a graphic of Notsip's data.  Iron or Aluminum Cylinders? What test conditions? What engine? | ||
| Aaron |
"I have seen where some of you speak of rocker boxes leaking. The problem that they are leaking is because of the excessive heat and the rubber gasket is failing." I suggest you do a little reading up on the subject, we've gone over this issue in some detail in the past. Many people have shared their experiences, including a dealership tech who has changed LOTS of them. I've probably fixed a couple dozen myself. There are even pictures of various failure modes. Bottom line, the failure modes and the fix are well understood and your information is inaccurate. "So if the rocker box gaskets are fialing that means that the umbrella valve are also failing. Without these working properly the excessive crankcase pressure that is created by the blow-by is going to go past the umbrella valve at a higher speed and is going to carry oil with it." Again, I would encourage you to read up on the subject. Not only are rocker gasket failures and umbrella valve failures unrelated, but slowing down the escaping blow-by to reduce spewage is not the function of the umbrella valve. We've discussed many times how the crankcase ventilation works and what the umbrella valve does. It's all in the archives. FYI, the factory actually shared some information with us about how to fix breather spewage, awhile back. I'm sure it's still in the archives somewhere, you should take a look. From what I understand, it's a good fix, which suggests that in many cases this problem is caused by casting imperfections in the rocker boxes instead of excessive blow-by. If you hang around here much, I think you'll find that a LOT of good experience has been shared and there's a pretty solid base of knowledge about what's going on with these motors. When a new guy comes on professing to be knowledgeable on a subject and then commences to teaching us about it, he's likely to get critiqued and corrected a lot, as you've seen happen. The bullshit filter is pretty effective and there's a tremendous potential to damage your own credibility when you offer information that's inaccurate and not well thought out. Not at all sure that's an effective marketing strategy. But whatever floats your boat. | ||
| Blake |
James, THANK YOU BROTHER!!! Notsip, I'm really having to bite my lip. Too much bullshit, followed by generalities, and vague assertions. Your presentation lacks any meaningful technical content. Then it turns out you are simply trying to peddle your products, again. I'm not pleased. | ||
| Hootowl |
Aaron, I had a nice little piece written up explaining the actual failure mode of the rockerbox gaskets (as well as pointing out other glaring tidbits of BS), but thought better of posting it. It seems fairly clear that Notsip isn't reading the replies to his ramblings and is only interested in saying what he has to say, right or wrong. | ||
| Hootowl |
Blake, I vote you kill this whole thread, lest some unsuspecting reader mistake it for useful information. | ||
| Hoser |
Blake: I second that . Spewage indeed !! |
