facthunter Posted June 7 Posted June 7 Silicone is an INSULATOR of heat and messy to deal with. You can't dissolve it. What purpose is it serving?. It's just another complication to deal with. The Plug washer is really a single use item. It's torqued till it flattens. The longer reach plugs have more of an issue. They can even get tight from oil carboning and require some careful easing and solvents to work them out without damage and to remove the head and heat it.. Aluminium is good at picking up metal when the fit is tight. It needs special lubricants when being machined...Threads in aluminium are often a problem. It's relatively soft and the threads easily shear. Thats why fine threads are not used. Some motors have a cast-in threaded bush for the plugs, made of strong bronze. There are recommended ways of coping with this. You might get away with doing none of it. but why not apply best practice? Prevention is better than cure. Nev.
Red Posted June 7 Posted June 7 Sigh....Its there to simply fill voids with something more heat conductive than nothing (there are many many voids in the crudely machined threads of a spark plug) Go tell the many people who fried their CPU because they forgot to apply thermal paste that it doesnt work This https://www.aircraftspruce.com/catalog/cspages/silheattrans.php is not the same thing as silicone sealant 1
skippydiesel Posted June 7 Posted June 7 "You might get away with doing none of it. but why not apply best practice? Prevention is better than cure. Nev." I can not imagine that there would not be a dissenting word again this sentiment Nev. Does this mean that you now support my position, on following Rotax service instructions, for the installation of spark plugs, in their 9 series engines? In case the above sentiment is not a change of heart by you: https://en.wikipedia.org/wiki/Rotax_912: Rotax 9's have been in production since 1989 (Certified production commenced in 1995). 50,000 units had been produced by 2014. Total flight hours is in excess of 45 million. Whatever service techniques you may legitimately use on other aircraft and ground based engines, it seems to me that the above achievements, by Rotax, strongly suggest following their (not your) service directions ie "apply best practice"😈 1
danny_galaga Posted June 7 Author Posted June 7 Spark plug debate here: https://www.recreationalflying.com/forums/topic/39835-rotax-9-series-engines-anti-seize-thermal-paste-nothing/
BurnieM Posted June 8 Posted June 8 Not trying to drag this out but; https://ngksparkplugs.com/en/resources/spark-plug-basics "The optimal firing end temperature is approximately 500°C (932°F) to 800°C (1472°F). The two most common causes of spark plug problems are carbon fouling (< 450°C) and overheating (> 800°C)." Is saving 10 degrees revelant ? https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs "NGK spark plugs feature trivalent plating. This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without lubrication or anti-seize. Anti-seize can act as a lubricant, altering torque values up to 20 percent, increasing the risk of spark plug thread breakage and/or metal shell stretch. Thread breakage can sometimes involve removing the cylinder head for repair. Metal shell stretch changes the heat rating of the spark plug and can result in serious engine damage caused by pre-ignition. Do not use anti-seize or lubricant on NGK spark plugs. It is completely unnecessary and can be detrimental." 50,000+ is a lot of engines but literally millions of motorcycle engines are running without this compound recommendation. The only motorcycle heat compound recommendation I can find is for Canam, also a BRP company. I am all for best practise but is Rotaxs recommendations it ? Show me the data, please. 1
skippydiesel Posted June 8 Posted June 8 Hi BurnieM, I refer you to Rotax 912 Line Maintenance as earlier stated Rotax, MAINTENANCE MANUAL LINE, Chapter 12-20-00, Page 57 "...................... Apply heat conduction compound sparingly and do not apply to the first three threads. Apply small amount of heat conduction compound to spark plug thread and tighten spark plug to 16 Nm (142 in. lb) on the cold engine
facthunter Posted June 8 Posted June 8 Skip. Silicone is not the kind of MUCK you want on a spark plug thread. It's weird stuff and is not a CONDUCTOR of heat. ALL these things will alter the tension feel. The washer crushes and you can feel that situation by hand. Heat removal from the spark plug body is not an issue if it's TIGHT. Thread wear could occur in aluminium, particularly with shorter reach plugs or ones that have been out of the Package floating around in a tool box. allowing tread damage and then there's the odd cross threading possibility. Nev
sfGnome Posted June 8 Posted June 8 (edited) Without wanting to get involved in this discussion, it’s worth noting that ‘silicon’ is not ‘silicone’. I think you’re talking about two different things. Edited June 8 by sfGnome
facthunter Posted June 8 Posted June 8 Silicon is in sand and glass. It's also sometimes used in aluminium alloys to lower the thermal expansion rate. It makes the alloy harder and more brittle and more dense. I can't recall the word "silicon" used in this discussion prior to now. Nev
danny_galaga Posted June 8 Author Posted June 8 11 hours ago, danny_galaga said: Spark plug debate here: https://www.recreationalflying.com/forums/topic/39835-rotax-9-series-engines-anti-seize-thermal-paste-nothing/
sfGnome Posted June 8 Posted June 8 9 hours ago, facthunter said: Silicon is in sand and glass. It's also sometimes used in aluminium alloys to lower the thermal expansion rate. It makes the alloy harder and more brittle and more dense. I can't recall the word "silicon" used in this discussion prior to now. Nev The picture of the Wacker tube says ‘silicon’. 1
Area-51 Posted June 8 Posted June 8 There is no consensus on this one... Best to play it safe by not starting the motor between each spark plug service 👍 1 3
danny_galaga Posted June 8 Author Posted June 8 7 hours ago, Area-51 said: There is no consensus on this one... Best to play it safe by not starting the motor between each spark plug service 👍 That's what I'VE been doing 😄 2
facthunter Posted June 9 Posted June 9 It's dead easy to google these things and find out. We should be able to discuss things like this sensibly. Jokes belong in the other section. Nev 1
danny_galaga Posted June 9 Author Posted June 9 4 hours ago, facthunter said: It's dead easy to google these things and find out. We should be able to discuss things like this sensibly. Jokes belong in the other section. Nev The joke is you seem to be ignoring what the Rotax engineers are recommending. Maybe you could write them a letter to tell them where they are going wrong? All this is making the spare parts thread needlessly long. 2
facthunter Posted June 9 Posted June 9 I've explained it fully all the way through. Rotax do suggest a few funny things at times. It's NOT blasphemy to question it. Plug heat transfer is NOT an issue. Silicone is not good at transferring heat. I do have a long and extensive experience with many kinds of Motors. Not just U tube. WHY BOG up threads with silicone? It's extremely difficult to clean off. It has VARYING outcomes. . Expensive and NOT necessary. On electrical sinks it holds the two pieces together in close proximity. You don't create a thick blob. Nev . 1 1
facthunter Posted June 9 Posted June 9 OK Hands up who has ever had a cooked spark plug in a 9xx motor.? . Don't tell me everyone uses wacker or something. Where are the examples?. Nev
skippydiesel Posted June 9 Posted June 9 2 minutes ago, facthunter said: OK Hands up who has ever had a cooked spark plug in a 9xx motor.? . Don't tell me everyone uses wacker or something. Where are the examples?. Nev If you purchase your Rotax plugs B from Floods, you have the option, for a small fee, to have the threads "treated" with the appropriate paste - I have never asked what brand but assume they would use Wacker P 12. This does not mean that all patrons of B Flood, go to the added small expense, however my money is that most will and those that don't will apply their own.
Blueadventures Posted June 9 Posted June 9 17 minutes ago, facthunter said: OK Hands up who has ever had a cooked spark plug in a 9xx motor.? . Don't tell me everyone uses wacker or something. Where are the examples?. Nev I have used Wacker on all plugs; bought a tube of it in 2010 for $18. Plugs have been good ULS now and UL previously. 2
facthunter Posted June 9 Posted June 9 I want evidence of the NEED for it. Isn't that reasonable?. I'm also an atheist for a similar reason. Evidence. Nev
skippydiesel Posted June 9 Posted June 9 5 minutes ago, facthunter said: I want evidence of the NEED for it. Isn't that reasonable?. I'm also an atheist for a similar reason. Evidence. Nev Not going to happen - Rotax Maintenance Manuals are THE WORD and THE WORD IS GOOD thus saith a Rotax owner, who doesn't want to risk damage to his 912ULS, by experimenting on leaving off a few cents worth of conductive paste. In the unlikly event, that you are correct and there is no benefit, neither can there be any harm, in applying the past as specified.😈
facthunter Posted June 9 Posted June 9 You are inconsistent. You argue about Rotax's oils being too expensive and infer they are ripping you off.. With this you say just use it anyhow. with a silicon(e) paste product. A metalised anti seize may conduct heat better than where Silicon doesn't allow such a good contact. One side of all the threads has excellent contact with the head metal when it's tightened and if it's all clean and the sealing washer collapsed properly. I suggest 144 inch Lbs may not be sufficient to reliably achieve that. You can feel it when done by hand if you know what you are doing.. Hey JUST show me ONE cooked plug or tell me what they look like and cause to happen . Nev 1
Red Posted June 9 Posted June 9 👇 https://www.recreationalflying.com/forums/topic/39835-rotax-9-series-engines-anti-seize-thermal-paste-nothing/ 1 1
danny_galaga Posted June 9 Author Posted June 9 (edited) 15 hours ago, facthunter said: I've explained it fully all the way through. Rotax do suggest a few funny things at times. It's NOT blasphemy to question it. Plug heat transfer is NOT an issue. Silicone is not good at transferring heat. I do have a long and extensive experience with many kinds of Motors. Not just U tube. WHY BOG up threads with silicone? It's extremely difficult to clean off. It has VARYING outcomes. . Expensive and NOT necessary. On electrical sinks it holds the two pieces together in close proximity. You don't create a thick blob. Nev . Oh, you don't have to explain it to us, we're good with it. Just email the Rotax engineers and tell them why they should stop recommending heat transfer paste. Be convincing and we'll all love you for it because then hopefully they'll recommend using nothing at all, saving us Rotax drivers money 🙂 But please, FFS, use this link for continued debate https://www.recreationalflying.com/forums/topic/39835-rotax-9-series-engines-anti-seize-thermal-paste-nothing/#comment-566016 Edited June 9 by danny_galaga 1
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