---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Tue 11/02/10: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:42 AM - 582 oil line questions (Dave G) 2. 03:19 AM - 912 uls exhaust gas analysis (ndibiase) 3. 05:36 AM - Re: 912 uls exhaust gas analysis (FLYaDIVE) 4. 05:49 AM - Re: Re: Prop Strike crank damage (Catz631@aol.com) 5. 06:55 AM - Re: 912 uls exhaust gas analysis (Robert Borger) 6. 11:05 AM - Re: 912 uls exhaust gas analysis (rampil) 7. 02:02 PM - Re: 912 uls exhaust gas analysis (Roger Lee) 8. 03:06 PM - Re: Re: Prop Strike crank damage (bjones@dmv.com) 9. 03:43 PM - Re: 912 uls exhaust gas analysis (ndibiase) 10. 08:53 PM - Re: 912 uls exhaust gas analysis (Roger Lee) ________________________________ Message 1 _____________________________________ Time: 02:42:13 AM PST US From: "Dave G" Subject: RotaxEngines-List: 582 oil line questions During maintenance I examined the oil supply line for my 582 and found it needs replacement. It has become more prone to kinking over time and I wish to replace it. The original builder used that "blue" tubing and I could use that but I am curious what others use. On the plus side the tubing does not appear to harden with age carrying oil as I have seen with fuel. Dave Goddard KF IV 1050 / 582 / Warp ________________________________ Message 2 _____________________________________ Time: 03:19:06 AM PST US Subject: RotaxEngines-List: 912 uls exhaust gas analysis From: "ndibiase" For diagnostic reasons after an over speed of unknown entity on my Savannah LSA plane (consequence : big power loss -500 rpm with perfect carbs , push rods and compression and leak down tests ok. Growing oil consumption, little misfiring) i had the suggestion to do an exhaust gas analysis on my rotax 912 uls (100 hrs from new). Infact after a boroscope analysis (with a very cheap but low res instrument) there is evidence of some partial burned oil in the combustion chambers (little spots dark orange caramel like appareance). Leakage can be suspected from valve stem guides. Someone has done an exhaust gas analysis on rotax 912 uls ? Is there experience on witch are the normal range value of Co, Co2 , HC ? If there is an oil leakage is it shown in altered HC reading values ? Thanks in advance , i am not an expert and i am very far from nearest rotax service center. Nicola di Biase Read this topic online here: http://forums.matronics.com/viewtopic.php?p=317834#317834 ________________________________ Message 3 _____________________________________ Time: 05:36:20 AM PST US Subject: Re: RotaxEngines-List: 912 uls exhaust gas analysis From: FLYaDIVE Nicola: I think someone is pulling your leg... Exhaust Gas Analyzation!!! Just look at your spark plugs. They should be DRY - GRAYISH in color, sometimes with a brownish tinge and evenly eroding. Eroding, should be ZERO in 100 Hours. Check the internet - Look for a CHAMPION SPARK PLUG INSPECTION CHART. It will give you spark plug color Vs cause. What color is your engine oil? When was the last time you changed the oil? Double Check the compression readings. Sure reads like you have a bad ring or two. Look at the exhaust pipe... Is is heavy with BLACK SOOT? It should be light gray to dark gray or maybe with a slight brownish tinge. It should also feel dry. Do you see any oil leaks around the engine? Is there oil spray under the cowl? Check your radiator - Any oil in the water? Barry On Tue, Nov 2, 2010 at 6:16 AM, ndibiase wrote: > > For diagnostic reasons after an over speed of unknown entity on my Savannah > LSA plane (consequence : big power loss -500 rpm with perfect carbs , push > rods and compression and leak down tests ok. Growing oil consumption, little > misfiring) i had the suggestion to do an exhaust gas analysis on my rotax > 912 uls (100 hrs from new). > > Infact after a boroscope analysis (with a very cheap but low res > instrument) there is evidence of some partial burned oil in the combustion > chambers (little spots dark orange caramel like appareance). > > Leakage can be suspected from valve stem guides. > > Someone has done an exhaust gas analysis on rotax 912 uls ? > > Is there experience on witch are the normal range value of Co, Co2 , HC ? > If there is an oil leakage is it shown in altered HC reading values ? > > Thanks in advance , i am not an expert and i am very far from nearest rotax > service center. > > Nicola di Biase > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=317834#317834 > > -- Barry "Chop'd Liver" ________________________________ Message 4 _____________________________________ Time: 05:49:33 AM PST US From: Catz631@aol.com Subject: Re: RotaxEngines-List: Re: Prop Strike crank damage Dick, Speaking of that English language bugaboo, did you mike the crank, i.e. check it's size with a micrometer, or indicate the crank, i.e. place a sensitive (resolution of .0001" or .005mm) dial indicator on the nose of the crank and check for runout as the crank is rotated? The latter is what is required after a prop strike, while the former is a nice to do but doesn't really tell you much unless there is evidence that the taper on the crank nose or the mating surface of the drive gear is damaged. See the Line Maintenance Manual, << Rick I just returned from vacation and was too pooped to talk let alone type! Too many errors. No,a dial indicator was applied to the crank to determine the runout and it was fine, gearbox check will be next.(will use the manual as a guide) Dick Maddux 912UL ________________________________ Message 5 _____________________________________ Time: 06:55:45 AM PST US Subject: Re: RotaxEngines-List: 912 uls exhaust gas analysis From: Robert Borger Nicola, One of the biggest issues with an overspeed in a 9xx is a piston contacting a valve. This can result in damage to the piston, a bent valve stem, damaged valve guide or damage to other parts of the valve train. The engine probably needs to be checked by a ROTAX repair shop to ensure everything in the valve train is OK. They will also have a better knowledge of what other things may go wrong as a result of an overspeed. Good luck! Bob Borger Europa Kit #A221 N914XL, XS Tri-Gear, Intercooled 914, Airmaster C/S Prop http://www.europaowners.org/forums/gallery2.php?g2_itemId=60232 http://www.biplaneforumgallery.com/index.php?cat=10046 Europa Flying! 3705 Lynchburg Dr. Corinth, TX 76208 Home: 940-497-2123 Cel: 817-992-1117 On Nov 2, 2010, at 5:16, ndibiase wrote: > > For diagnostic reasons after an over speed of unknown entity on my Savannah LSA plane (consequence : big power loss -500 rpm with perfect carbs , push rods and compression and leak down tests ok. Growing oil consumption, little misfiring) i had the suggestion to do an exhaust gas analysis on my rotax 912 uls (100 hrs from new). > > Infact after a boroscope analysis (with a very cheap but low res instrument) there is evidence of some partial burned oil in the combustion chambers (little spots dark orange caramel like appareance). > > Leakage can be suspected from valve stem guides. > > Someone has done an exhaust gas analysis on rotax 912 uls ? > > Is there experience on witch are the normal range value of Co, Co2 , HC ? > If there is an oil leakage is it shown in altered HC reading values ? > > Thanks in advance , i am not an expert and i am very far from nearest rotax service center. > > Nicola di Biase ________________________________ Message 6 _____________________________________ Time: 11:05:33 AM PST US Subject: RotaxEngines-List: Re: 912 uls exhaust gas analysis From: "rampil" I agree with Bob. The engine manuals are free for the taking on the web and tell you exactly what to do in case of an engine overspeed or other issue. If you are working in isolation, read the books and don't bother asking advise from people who are not very familiar with the Rotax. It is not like other aircraft engines in many ways. Gas analysis is not a routine procedure, is not recommended by Rotax, and would not be the best way to diagnose bent lifters and bad, floated valves from an overspeed. -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=317880#317880 ________________________________ Message 7 _____________________________________ Time: 02:02:03 PM PST US Subject: RotaxEngines-List: Re: 912 uls exhaust gas analysis From: "Roger Lee" Hi Nicola, How bad was the over speed? With prop or without? How long? Do all of the engine temps and pressures look good and do you have all the read outs? (EGT, CHT ect...) You said now that oil is constantly used? What does the inside of the exhaust pipe look like? (Oily, dry, black soot, gray soot ect...) There is a procedure in the maint. manual for the over speed check, but these guys are right that a Rotax shop should do the check. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Repair Center Home 520-574-1080 TRY HOME FIRST Cell 520349-7056 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=317894#317894 ________________________________ Message 8 _____________________________________ Time: 03:06:22 PM PST US Subject: Re: RotaxEngines-List: Re: Prop Strike crank damage From: bjones@dmv.com VHJ5IHRoZSBSb3RheCB0ZWNobmljYWwgaGVscCBsaW5lIGF0IExvY2t3b29kIEF2aWF0aW9uIGlu IFNlYnJpbmcgRmxvcmlkYSBhbmQgYXNrIGZvciB0aGUgaGVhZCBvZiB0aGVpciBSb3RheCBzaG9w IEtlcnJ5IGZvciBtb3JlIGRldGFpbHMgb24gcm90YXRpb24gb2YgdGhlIGNyYW5rIHNlY3Rpb25z IHdoZXJlIHRoZXkgYXJlIHByZXNzIGZpdCB0b2dldGhlciBjYXVzZWQgYnkgcHJvcCBzdHJpa2Uu DQpUaGF0IGxpbmUgaXMgb3BlbiBmb3IgYW4gaG91ciBpbiB0aGUgYW0gYW5kIGFuIGhvdXIgaW4g dGhlIGFmdGVybm9vbiBlYXN0ZXJuIHRpbWUuIENhbid0IHJlbWVtYmVyIGhvdXJzLg0KVGhleSBo YXZlICBhIHRlY2huaXF1ZSBhbmQgZXF1aXBtZW50IHRvIG1lYXN1cmUgdGhlIHJvdGF0aW9uIG9y IHR3aXN0Lg0KRGVhbiB3aG8gcnVucyB0aGUgUm90YXggSW5zdGl0dWUgZGlkIG5vdCBicmluZyBp dCB1cC4NCkkgc3VzcGVjdCB0aGF0IHRoZSBwcm9ibGVtIGRpYWdub3NpcyBhbmQgc29sdXRpb24g b2YgY3Jhbmsgc2hhZnQgcm90YXRpb24gYXQgcHJlc3MgZml0IGp1bmN0aW9uIGlzIHVuZGVyIHNj cnV0aW55IGJ5IFJvdGF4IGFuZCBub3Qgb3V0IG9mZmljaWFsbHkgeWV0Lg0KTXkgaW1wcmVzc2lv IHdhcyB0aGF0IHRoZSBwcm9ibGVtIGlzIHByaW1hcmlseSBpbiBub24gc2xpcHBlciBjbHV0Y2gg ZW5naW5lcyBidXQgbm90IGV4Y2x1c2l2ZWx5Lg0KQiBKIA0KTjE1NEsgDQpONjI2TlINCg0KU2Vu dCBmcm9tIG15IFZlcml6b24gV2lyZWxlc3MgQmxhY2tCZXJyeQ0KDQotLS0tLU9yaWdpbmFsIE1l c3NhZ2UtLS0tLQ0KRnJvbTogQ2F0ejYzMUBhb2wuY29tDQpTZW5kZXI6IG93bmVyLXJvdGF4ZW5n aW5lcy1saXN0LXNlcnZlckBtYXRyb25pY3MuY29tDQpEYXRlOiBNb24sIDEgTm92IDIwMTAgMDc6 NTI6NTcgDQpUbzogPHJvdGF4ZW5naW5lcy1saXN0QG1hdHJvbmljcy5jb20+DQpSZXBseS1Ubzog cm90YXhlbmdpbmVzLWxpc3RAbWF0cm9uaWNzLmNvbQ0KU3ViamVjdDogUmU6IFJvdGF4RW5naW5l cy1MaXN0OiBSZTogUHJvcCBTdHJpa2UgY3JhbmsgZGFtYWdlDQoNCkJKLA0KIFRoYW5rcyBmb3Ig dGhlIGdvb2QgZXhwbGFuYXRpb24gZm9yIHRoZSBwdXJwb3NlIG9mIHRoZSBzbGlwcGVyIGNsdXRj aC4gTQ0Kb3ZlbWVudCBvZiB0aGUgY3Jhbmsgc2VjdGlvbnMgd2FzIG5vdCBtZW50aW9uZWQgaW4g bXkgUm90YXggY291cnNlcy4uKG9yIHRoYXQgDQpJIHJlbWVtYmVyKSBNYWtlcyBwZXJmZWN0IHNl bnNlLiBMZWFybiBzb21ldGhpbmcgbmV3IGV2ZXJ5IGRheS4NCiBTb3JyeSBhYm91dCB0aGUgbWlz IGludGVycHJldGF0aW9uIG9mICJjb21wb3NpdGUiIGFzIGl0IGFwcGxpZXMgdG8gdGhlIA0KY3Jh bmtzaGFmdC4gQ29tcG9zaXRlIHRvIG1lIGlzIGxpa2UgY2FyYm9uIGZpYmVyLCBrZXZsYXIsZXRj IChpZTsgb3RoZXIgdGhhbiANCnN0cmFpZ2h0IG1ldGFsKSBQZXJoYXBzIGEgc2VjdGlvbmFsIGNy YW5rc2hhZnQgb3Igc3VjaCB3b3VsZCBoYXZlIGJlZW4gDQpjbGVhcmVyLiAoYWhoaCB5ZXMuLi5F bmdsaXNoKQ0KIFdoaWNoIGJyaW5ncyBtZSB0byB0aGUgcG9pbnQ6DQogV2UgaGFzIGEgUmFucyBT LTYgZmxpcCB1cHNpZGUgZG93biBhIGZldyB3ZWVrcyBhZ28gZHVyaW5nIGxhbmRpbmcuIEl0IA0K YnJva2UgdGhlIFdhcnAgcHJvcCBibGFkZXMsIG9pbCB0ZW1wIGhvdXNpbmcsKHNlbmRlciBicm9r ZSB0aGUgaG91c2luZykgYW5kIHdhcyANCmF0IGlkbGUgdGhydXN0LiBXZSByZXBsYWNlZCB0aGUg aG91c2luZyxtaWtlZCB0aGUgc2hhZnQoT0spIGFuZCBzdGlsbCBoYXZlIA0KdGhlIGdlYXJib3gg dG8gY2hlY2suIEkgd29uZGVyIGlmIHRoZXJlIGNvdWxkIGJlIGEgY3JhbmsgcHJvYmxlbShpZTog c2VnbWVudCANCm1vdmVtZW50KSBvciBkb2VzIGluIGZhY3QsIHRoZSBzbGlwcGVyIGNsdXRjaCBm dWxseSB0YWtlIGNhcmUgb2YgdGhhdC4NCiBJIGhhdmUgYmVlbiBvbiB2YWNhdGlvbiBzbyBoYXZl IG5vdCBkb25lIGFueSBvZiB0aGUgd29yayBteXNlbGYNCiAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICBEaWNrIE1hZGR1eA0KICAgICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDkxMlVMDQogICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgTWlsdG9uLEZsDQo ________________________________ Message 9 _____________________________________ Time: 03:43:28 PM PST US Subject: RotaxEngines-List: Re: 912 uls exhaust gas analysis From: "ndibiase" Roger Lee wrote: > Hi Nicola, > > How bad was the over speed? With prop or without? How long? Do all of the engine temps and pressures look good and do you have all the read outs? (EGT, CHT ect...) > You said now that oil is constantly used? What does the inside of the exhaust pipe look like? (Oily, dry, black soot, gray soot ect...) > There is a procedure in the maint. manual for the over speed check, but these guys are right that a Rotax shop should do the check. Over speed was of unknown entity , perhaps > 6200 rpm (i was forced to do a sudden collision avoidance maneuver in the traffic circuit with full throttle, high airplane speed and bad -minimum pitch- variable propeller setting) but it last for only 2-3 seconds. After that ,there was huge power loss (550 rpm) , CHT normal, EGT with no abnormal sign (max 30 Celsius spread between cylinder couple and 90 between front and rear). Very little misfiring at low load/rpm. Oil consumption has gone from almost negligible to 250 gr. in 2-3 hour. Leak down test and compression test perfect. carbs and leverages are ok. spark plug seems ok. Boroscope analysis (with a very cheap and low res instrument) showed evidence of some partial burned oil in the combustion chambers (little spots dark orange caramel like appearance) but i am not an expert and this is my first time of using this kind of instrument in an engine. There was also a very subtle sign. Oil recovery procedure (the "gurgle") takes much more propeller turns than before. I am not a mechanic but, in my humble opinion, this can be sign of valve stem guide problems (crankcase pressure escape from the valve guides- heads in 912 are pressurized ). Is it a reasonable hypothesis ? There is some black soot in the exhaust. i know that in case over speed > 6200 rpm Rotax maint. manual states "the whole engine must be inspected......and i will contact nearest rotax heavy maintenance center. But i'd like to do a logical analysis before to open the engine. My summary : If is it a valve train problem it is strange that leak down and compression tests are perfect. if is it a crankshaft problem it seems very strange to have not a lot of engine vibrations. i'd like to know how common and what are the usual signs of crankshaft problems in 912 ULS?. thanks Nicola di Biase Read this topic online here: http://forums.matronics.com/viewtopic.php?p=317910#317910 ________________________________ Message 10 ____________________________________ Time: 08:53:45 PM PST US Subject: RotaxEngines-List: Re: 912 uls exhaust gas analysis From: "Roger Lee" I sent Nicola's comments in for a second opinion and here is what was said. This come from way up the food chain and should be considered very good information to follow. Roger First, what was the differential pressure test result per cylinder, to just say its ok is not good enough in this case. While the book says you can accept 25% loss I would not personally, anything over 10 would send an alarm bell ringing for me. Indeed, if the RPM was high enough the only way you would do anything is if you kissed a valve and perhaps bent a push rod or two. If the report is correct higher oil consumption might indicate damage to the oil ring(s) and that might have happened in the case of cracking the piston ring lands if the piston hit the head(s) For sure since he reports performance loss treat it as requiring more in-depth inspection. Remove the heads, check all the push rods and pistons. With the heads off you will know right away if you have a sticking valve. If you have any bent push rods pull all the valves and check for bent valve faces. On the good side, if no valves hit the pistons it is extremely unlikely to have caused any crankshaft problems, so this should be fine. The report that it is harder to get it to gurgle can be a sign of perhaps damaged rings, or leaking valves, both of which would cause the engine case pressures to be slightly lower and affect the case pressure. My recommendation, bring it to someone who can do a good evaluation of the top end. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Repair Center Home 520-574-1080 TRY HOME FIRST Cell 520349-7056 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=317937#317937 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rotaxengines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RotaxEngines-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rotaxengines-list Browse Digests http://www.matronics.com/digest/rotaxengines-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.