Blueadventures Posted May 23 Posted May 23 13 minutes ago, skippydiesel said: FYI BMW Bing choke return spring about $7.50 each. Not sure of the Rotax Bing choke return spring cost but $23.85 delivered (express post) What occurred? Rusted through or lost the original. May pay to get 2 or 3 depending on the condition of the spring on the other carby. 2
skippydiesel Posted May 23 Posted May 23 Near new engine - did a Mandatory SB on carburettors. Had a bag for L/R carby parts. Dont know how? Dont know when? One choke return spring went AWOL. New spring on way - Back in the air very soon😈
Blueadventures Posted May 23 Posted May 23 41 minutes ago, skippydiesel said: Near new engine - did a Mandatory SB on carburettors. Had a bag for L/R carby parts. Dont know how? Dont know when? One choke return spring went AWOL. New spring on way - Back in the air very soon😈 OK, your Zephur should be flying soon; RAA are currently processing it.
Area-51 Posted May 23 Posted May 23 Earlier springs were zinc plated and rusted out over time. Latest Rotax choke and throttle springs are stainless. Throttle arms should be upgraded to those with integrated nylon spring retention bush to prevent failure.
skippydiesel Posted May 24 Posted May 24 46 minutes ago, Area-51 said: Earlier springs were zinc plated and rusted out over time. Latest Rotax choke and throttle springs are stainless. Throttle arms should be upgraded to those with integrated nylon spring retention bush to prevent failure. Not the throttle spring - choke return spring - PN 938286 (no nylon/plastic inserts)
skippydiesel Posted May 24 Posted May 24 15 hours ago, Blueadventures said: OK, your Zephur should be flying soon; RAA are currently processing it. Yeah! Thanks for that. Had heard - even seen some photos - looks great
BrendAn Posted May 24 Posted May 24 1 hour ago, skippydiesel said: Yeah! Thanks for that. Had heard - even seen some photos - looks great Is it a mk 3 with twin Su,s 4
skippydiesel Posted May 24 Posted May 24 3 hours ago, BrendAn said: Is it a mk 3 with twin Su,s Obviously a mature Ford lover😈 1
skippydiesel Posted May 28 Posted May 28 Of possible interest: https://www.silent-hektik.de/UL_R_912.htm
skippydiesel Posted June 1 Posted June 1 MG Chemicals Heat Transfer Compound Silicon - substitute for Wacker P12 Paste as recommended by Rotax for use on spark plug thread. Almost impossible to find Wacker in Australia (at a reasonable price). MG Chemicals Heat Transfer Compound Silicon comes highly recommended by Rotax Owners Forum technician and is available in AU. https://www.rotax-owner.com/en/912-914-technical-questions/9293-is-this-spark-plug-thermal-paste-ok?start=15 Page 4 Best price I have found, $27.53, is from CLC Tech Australia https://clctech.com.au/mg-chemicals-heat-transfer-compound-silicone-150g.html 1
skippydiesel Posted June 1 Posted June 1 (edited) 1 hour ago, danny_galaga said: I just went to Jaycar Yeah! but what product ?? and does it meet Rotax specifications ?? Lots of heat sink paste products out there but only a few suitable for spark plug to aluminum head, heat & electrical conductivity. Edited June 1 by skippydiesel 1
danny_galaga Posted June 2 Author Posted June 2 Who knows? It has silver in it, conducts heat and electricity. Just like in heatsinks, it doesn't conduct heat nearly as well as metal to metal, but it does conduct way better than air. You are only filling in the tiny air gaps that appear between the threads. Much of the heat, and probably all of the electrical current is being conducted metal to metal. 1
facthunter Posted June 2 Posted June 2 An anti seize is a must. and plug correctly torqued. That crushes the washer properly. Could be too hot for silicone. No one ever mentions Hot and cold plugs which surprises me. Nev
skippydiesel Posted June 2 Posted June 2 1 hour ago, facthunter said: An anti seize is a must. and plug correctly torqued. That crushes the washer properly. Could be too hot for silicone. No one ever mentions Hot and cold plugs which surprises me. Nev Rotax specifically warn against anti seize for spark plugs. Rotax recommended product is a heatsink paste, Wacker P12 Paste. Difficult to find in Au - hense my suggestion of MG Chemicals Heat Transfer Compound Silicon. 1
spacesailor Posted June 2 Posted June 2 Unlike me . They all use what is specified. Have you seen the size of those ' Old ' VW spark plugs . I will try anything to save a " gram " or two . Plus the " original " plugs are no longer manufactured. spacesailor
skippydiesel Posted June 5 Posted June 5 On 01/06/2024 at 2:44 PM, skippydiesel said: MG Chemicals Heat Transfer Compound Silicon - substitute for Wacker P12 Paste as recommended by Rotax for use on spark plug thread. Almost impossible to find Wacker in Australia (at a reasonable price). MG Chemicals Heat Transfer Compound Silicon comes highly recommended by Rotax Owners Forum technician and is available in AU. https://www.rotax-owner.com/en/912-914-technical-questions/9293-is-this-spark-plug-thermal-paste-ok?start=15 Page 4 Best price I have found, $27.53, is from CLC Tech Australia https://clctech.com.au/mg-chemicals-heat-transfer-compound-silicone-150g.html Sorry Folks! - CLC Tech claim that the price above is an old one, that they will not honour. Next best price seems to be Mektronic $65.15 (delivered AU) https://mektronics.com.au/products/mg-chemicals-heat-transfer-compound-silicone-150g 1
skippydiesel Posted June 5 Posted June 5 20 minutes ago, danny_galaga said: Damn, big jump in price 😲 Yeah! The good things about this product; Available in AU Highly recommended by Rotax Owner Forum technical expert One tube will likly last an owner maintainer, the whole life of the engine (very little used per plug & usually only one application/new plug every 200 hrs) Cheaper than Rotax recommended Wacker P12 Paste (if you can find it) Down side; Price May deteriorate with age ?? - Need to find a way to seal tube between uses.
spacesailor Posted June 5 Posted June 5 Use it for your plugs , then onsale it at half price to ' mates ' . How many plugs per tube are expected to treated , ( at a smear per plug ) . spacesailor 1
facthunter Posted June 6 Posted June 6 I'd just use Anti seize. I don't know how silicone takes the possible heat. The main thing is to look after the alloy thread in the head.. A helicoil is not a suitable repair. for spark plug threads. Nev 1
skippydiesel Posted June 6 Posted June 6 31 minutes ago, facthunter said: I'd just use Anti seize. I don't know how silicone takes the possible heat. The main thing is to look after the alloy thread in the head.. A helicoil is not a suitable repair. for spark plug threads. Nev I can not make an informed comment, other than to say when it comes to Rotax product recommendations, I go by their advice, whenever possible. In this case (heat sink compound for spark plugs) Rotax advise Wacker P12 Paste - very difficult to find in Au. Rotax Owners Forum technician Roger Lee, has suggested MG Chemicals Heat Transfer Compound Silicon as an appropriate substitute, that he has used to good effect for 23 years. https://www.rotax-owner.com/en/912-914-technical-questions/9293-is-this-spark-plug-thermal-paste-ok?start=15
facthunter Posted June 6 Posted June 6 (edited) A properly tensioned spark plug will allow adequate heat transfer. The area of a plug exposed to flame is not large with a 14 mm plug. even better with smaller ones. The point is that it's consistent and if the plug exhibited an overheat of the insulator, internally. (The ONLY bit that matters) you would adjust to a cooler heat range. Nev Edited June 6 by facthunter expand 1
Red Posted June 6 Posted June 6 2 hours ago, facthunter said: I'd just use Anti seize. I don't know how silicone takes the possible heat. The main thing is to look after the alloy thread in the head.. A helicoil is not a suitable repair. for spark plug threads. Nev The whole point (according to Rotax) is for heat transfer purposes.
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