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I was reading an article that was written several years ago in one of the motorcycle magaizines by a reported British bike mechanic with several years experience working with British motorcycles. He advised that there was no reason to retain the sludge trap tube. He further advised that with modern detergent oils that the sludge tube was not needed. That the only negative was a slight reduction in oil pressure, that was not altogether bad since Triumph oil pumps could reach pressures in excess of 80lbs., which could wipe out rod bearings. Concidering modern oils & the use of a return line oil filter, I think that the sludge tube system is bacically usless. I can't think of any other manufacture that uses such an archaic system of oil filteration. I would welcome any comments concerning this view.
I've been hearing the same thing all my life it seems . One school of thought is that it doesnt hurt anything to clean it and leave it in , another is that when removed you may need to rebalance even if you replace the old caps with the hex caps it may affect balnce yet another is to remove the sludge tube and insert drill rod to add rigidity to the crankshaft???
The Triumph engine has a positive displacement oil pump so any reference to gain or loss of oil pressure is a bit odd, as is the proposition that high oil pressure may "wipe out" the shell bigends, the engine has an oil pressure relief valve in any case. Oil has to be fed to the drive side bigend, if Triumph had not provided a generous sludge trap a small oilway would have served the same purpose until it blocked at not much mileage. Everyone who runs these engines today should be using an external filter of the paper/cellulose type, the technology was simply not available to produce a good 15 micron/90% filter at a reasonable cost until the early 1960s', felt and wire gauze was standard on Velocette and Enfield and the Triumph had the sludge trap. Modern detergent oils are better by a long shot than the monogrades of old, and detergents and such are designed to keep solids in suspension so that a modern filter can remove them from the oil stream. I would happily run a non sludge trap crank on Penrite HPR-30 or equivalent with an external filter. However there are blokes who reckon that the sludge trap is an excellent "oil polishing" filter in that it will multipass trap sub 15 micron particles, the Boffins reckon that 10 micron or smaller cannot cause engine wear.
If you subsitute a correctly sized oil galley instead of a sludge trap then it will not fill up with gunge, the oil flow will keep it permanently clear. This is the principle used on most car cranks.
Yes, but Kommando, you flush all of the debris, wear bits, and combustion residue that works its way past the rings through the rod bearings... Is this a plan? While several different materials can be used for rod bearing shells (shells designed for high performance are made from harder materials which do not allow the swarf to imbed into a soft surface and protect the rod journal) shells designed to be used on the street have a soft top layer. While a filter will absorb most of the swarf floating around the motor when modern oils are used, the centrifugal force "sludge Tube" filter is much more efficient. Bearing makers have intentionally used softer materials in rod shells that are to be used in street motors. The thought is that the swarf imbeds it self into the soft shell instead of sitting on top of the surface where it acts like sandpaper. They are looking for longevity - not to protect from heavy pounding the rod shells get from of a race motor. Without leaving the Triumph group we can see the difference between the filtration and rod bearing failure and crank journal wear. Triumph 500 - 650 - 750 motors with their sludge tubes, seldom need their crankshaft journals ground (usually only after the motor was run after the sludge tube filled up). This is not the case with the Trident, which like a car, only has a conventional gauze filter. When I take apart a trident I expect to see undersize rod and main crankshaft journals and have the crankshaft ground. If one was to look at my percentage of sales of rod shells for the Triumphs that incorporate the sludge tube, the split would look like 100 sets of std, 12 sets of .010" under, 2 sets of .020" under and .5 sets of .030" under. While the triple rod bearing shells would almost be even across the sizes: for each std set I sold; I sold 1 set of .010", 1 set of .020" and 1 set of .030". Personally, where I can (Nourish exception) I use both type of filters.
Just pointing out that getting rid of the sludge trap does not mean blocked oil ways in a few 1000 miles. Always fit a return oil line filter, always clean the sludge trap on a stripdown but don't stripdown just to clean the sludge trap is my advice.
I just removed my sludge tube yesterday after the oil pump slider block disintergrated. What I found were finely ground particles of aluminum and some larger shavings in the sludge trap cavity. They were also inside and around the sludge trap tube. My tube is open at both ends with two 5/32" holes in the middle of the tube. I suppose that the tube trapped some of the debris but a good portion of it got through the tube and into the rod bearing oil passages. To think that the sludge trap/tube stops all debris from reaching the bearings until it fills up like and oil filter would do, seems unrealistic. I really believe that a return line oil filter of good quality is the answer, whether the tube is retained or removed. By the way, I weighed my sludge tube at 1 1/4oz. or 37grams. I would have to rely on someone with experience in balancing crankshafts to know how much this would effect the overall balance of the motor.
Not sure how true it is but a full sludge trap will vary the balance factor by 12%. The sludge trap was designed to filter out the small heavy particles, aluminium shavings do not fall into that catagory.
Not sure how true it is but a full sludge trap will vary the balance factor by 12%. The sludge trap was designed to filter out the small heavy particles, aluminium shavings do not fall into that catagory.
Quote Originally posted by kommando: Not sure how true it is but a full sludge trap will vary the balance factor by 12%. I don't think so. Maybe if you filled the entire sludge trap with lead?
Could I be so bold as to ask how metal from the oil pump drive block made its way out of the timing cover, past the pick-up tube screen in the sump, back through the oil pump return plungers, up to the oil tank, back throgh the oil tank filter, into the feed side of the oil pump to be delivered to the sludge tube. Wow, I always new that these pumps were self primig when some swarf lifted one of the balls off the seat, but those 4 valve pumps must be much better than I ever believed. I would like to see this... got pictures? Given that the Triumph balance figures assume that the sludge tube is full of oil, how much denser would sludge be than the oil that fills the cavity anyway. Sure a bit heavier, but 12%?
John, I'm not an engineer nor have anywhere as much experience as you. All I can tell you ia that the majority of the shavings were collected at the sump screen. However, some of the shavings coming off the drive block were ground up by the tining gears and found there way to the sump trap and the rod bearings. Also some of the shavings/debris found ther way through the two holes between the timing side an the crankcase. I wish I had I digital camera so I could show you some pictures. After fixing my bike, that will be my next purchase. As far as the balance factor, I have heard anywhere from 76% to 85% so I don't know whether removing the sludge tube would be benefical one way or the other. Thanks fo Your Comments, Ken
I have taken to many sludge traps out that were nearly blocked, to do away with them, even when using a filter. I also doubt that the amount of weight in a full trap would change the balance factor by enough for anyone to feel the difference. I have ridden bikes with factors from 47% to 87% on road engines ( 650 units) without a great deal of difference at 3-5k. I believe it is much more important that the outter webs be the same weight, (which demands dynamic balaning) than the exact balance factor of a given engine. I'm sure the expected RPM range that the engine is to be used,will also have a great effect on your choice of BF. I normally use 87% Dynamic. Seems to work for me. Dick
Quote Originally posted by Tiger73: I was reading an article that was written several years ago in one of the motorcycle magazines by a reported British bike mechanic with several years experience working with British motorcycles. He advised that there was no reason to retain the sludge trap tube. He further advised that with modern detergent oils that the sludge tube was not needed. ...Considering modern oils & the use of a return line oil filter, I think that the sludge tube system is basically useless. I can't think of any other manufacture that uses such an archaic system of oil filtration. I beg to differ, sir. The Triumph sludge tube is a centrifugal filter. It slings any particle heavier than air (and this also includes the oil itself) to the outside of the tube with the effective weight of several G's. If you've ever been to the fair and ridden one of those round rooms that spins at 300 RPM and has the floor drop out, then you know how the dirt in the oil feels. Except in this case, the "room" is spinning at 4000 RPM and hardly anything escapes. It doesn't matter if you run non-detergent oil, detergent oil, synthetic oil, mineral spirits, baby lotion, or what ever. Nothing but nothing can escape the pure and simple centrifugal effect created by the sludge tube design. The grit can't escape the sludge tube any easier than you could get up and walk out of the spinning room at the fair! So IMHO the base idea (that the sludge tube design no longer works) presented in the magazine article is totally preposterous! It simply goes against the laws of physics. What IS dated is that's it's clearly the "filter of last resort". When you run detergent oils the sludge tube will fill faster since grit does not settle out in the oil tank, as it did with non-detergent oils "back in the day". So clearly these days everyone needs a paper filter on their return line. But that does not validate taking out the tube. That's like saying "throw away your fire extinguishers because we have a smoke detector". Further more, LOTS of modern engines run a centrifugal oil filter: All Honda singles (only excluding the largest FT500 and XR650) which includes thousands of C15, Z50, SL65, SL70, XL70, XR75, XR80, S90, SL100, SL125, XL250, XL350. Then there's all the Honda twins 160, 305, CB350, CB360, CB450, CB500T, etc. Jez, simply too many to mention. And we haven't even gotten to the Suzuki, Yamaha, and Kawa 4-cycle engines. Frankly speaking brother, my question is how could anyone buy a motorcycle that was designed in 1938 and then comment in 2007 that the design might be "archaic"?
Gotta agree with John and RF, I've taken down a '66 BSA A65 and a '66 TR6 in the last two years and found the sludge trap contents to be alarming. Judging by the exterior condition of these engines, the previous owners lacked a lot in mechanical ability and maintenance skills. Both engines got new STANDARD big end shells, the crank journals were in excellent condition. The BSA even got put back together with the original TS main, measured out at .003, outside limitation of service limit. (I know, FEAR!,FIRE, FOES! yada yada...)nevermind. I have to attribute the good condition of the internals to the type of filtration. I was afraid of my sludge traps...now they are my best friends in the engines. Great description/explaination of sludge trap function RF, I think they would not be so reviled if they had called them 'centrifugal filtration system'.
Ok, boys there will be a meeting down at the club house tonight... I'll bring the gloves. I guess it's put up or shut up time!
OK, I have a problem, my operator's manual for the TRW mentions the sludge trap, but it is for a different "mark" than mine. I have 2 damaged cranks in the garage (like that when I got them, but I am packrat), and I cannot see what I am looking for. The last time I was in the cases was in 1979, and I knew not then what I kno now, not a lot of miles on it since, but now I have a bad crankshaft oil seal to deal with (original '56!), so while I am in there.... Oh yes, add thje humble Honda CD175 (late 60's on) to the centrifugal filter list!.
Thank you RF.I was racking what passes for my brain about what kind of engine it was,that I used to clean the centrifugal oil filter in all the time. Your post brought it all back.It was my first real motorcycle,with gears and clutch,and all.A Honda SL100.It was a dirt bike,and got ridden every day.It's oil was changed at least once a month,with sludge trap cleaning as well.I was always amazed at how much crud would be packed in there!
I'm afraid I must agree with you on this one RF Whatley. Remember, if you fit a smoke detector, don't throw away your fire extinguisher.
It's funny that this sludgetrap thing has just come up as I just redid the old '70 T-120 which has a total of 177,000 on it. I have always used 20-50 detergent, changed at about two thousand miles. This engine has never had a filter and the crank still mic's up to factory specs. The other bike,another '70 T-120 does use a filter using the 3 cylinder filter element and is necessay as this engine is a homebuilt 76% crank which,of course, not longer has the infamous sludgetrap.It now has 56,000 on it and I change the filter element every other time as I always take the old filter apart to see what it has trapped and it is quite clean. And John, I AM seriously considering going to the Chachuma rally, as the Mulreen's are not going to be able to continue this great rally. I wouldn't even laugh if you rode one of those "newfangled thingys"
To be "perfectly clear" slugetube filters are GREAT. Dick
Gang - Somewhere in all this... I see a T-shirt!
Quote Originally posted by RF Whatley: I see a T-shirt! Like this one?
Brilliant. Alex, you need to copyright that, and quickly!
I'm sure the system is effective, but IDK how small a particle (microns) the centrifugal speed of the crank will remove. Disregarding the tube radius, the rotational speed is based on the stroke (82mm - 3.228") is 10.14" per rotation, and at 4,000 RPM (high cruising speed) that's only 56 f/s. Gravel will come out, specs of dust won't. Once the particle size and relative density (S-G) fall below a critical level the particle/oil mix becomes a colloidal suspension (like milk) and will not separate out easily. Happily, the centrifuge is most effective at removing the most dense particles and most abrasive to bearings and ahsfts: iron and steel. The relative density of carbon or aluminum vs. oil is much closer, those these won't come out until higher speed, or lower viscosity. Yes, revving the engine with the oil hot cleans it better! In short: frequent oil changes remove even more.
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