Tucano Posted August 23, 2019 Share Posted August 23, 2019 Is any one with a 914 interested in a set of Sodium Valves to suit their engine? Rotax is recommending that the valves be changed at overhaul but I am sure non one could afford them - try and get a price. I have made contact with a manufacturer engine valves that has Rotax blanks for sodium valves and based on a quote about 18 months ago a order for 24 would be $1K for four. Standard Rotax exhaust vales are about $US300 each so the price in good. I will fun the purchase with a deposit of 30% non refundable if order is cancelled. Would need 3 buyers outside myself Credits card is OK. Link to comment Share on other sites More sharing options...
facthunter Posted August 23, 2019 Share Posted August 23, 2019 Sodium is not what they are made of . It's in the hollow valve stems and in liquid form shakes around and gets more heat out of the valve head. The hollow stems are reduced in strength consequentially, making them a "lifed" component and inescapably expensive, due to the design. Nev Link to comment Share on other sites More sharing options...
onetrack Posted August 24, 2019 Share Posted August 24, 2019 Sodium-cooled valves are an expensive cure for short valve life. Stellite valves are a more affordable, and nearly as durable, option. Sodium-cooled valves do have a slight advantage as regards lightness, for very high RPM operation. Link to comment Share on other sites More sharing options...
Tucano Posted August 24, 2019 Author Share Posted August 24, 2019 Rotax is using these in the 915 and based on my info its for the 2000 hours - that enough life for anyone. These are only for someone operating a boosted engine looking for improved combustion cooling, a 80hp 912 does not need them. If am rebuild any engine at 2000 hours, the exhaust valves are for the bin, replacements are $1500 US plus, they can just do four for $800 euro and that is cheaper than Rotax plain exhaust valves. So again asking Link to comment Share on other sites More sharing options...
facthunter Posted August 26, 2019 Share Posted August 26, 2019 Keeping the valve head below a certain temp may be an issue also with the boosted engine. As is always the case., extra heat must be dissipated. They would not do it if it wasn't necessary. Nev Link to comment Share on other sites More sharing options...
Tucano Posted August 26, 2019 Author Share Posted August 26, 2019 We have 43'' available at take off with the supercharger - never been a issue to date Link to comment Share on other sites More sharing options...
Kyle Communications Posted August 26, 2019 Share Posted August 26, 2019 Isnt the TBO for the 912IS at 1500 hrs?....supposed to be maybe going longer but at this time it is limited to 1500 Link to comment Share on other sites More sharing options...
Tucano Posted August 26, 2019 Author Share Posted August 26, 2019 My error, but lots of hours. Link to comment Share on other sites More sharing options...
M61A1 Posted August 28, 2019 Share Posted August 28, 2019 At first glance this appears irrelevant, but I think it is quite relevant...... https://www.recreationalflying.com/forums/topic/67272-how-many-forum-posters-does-it-take-to-change-a-light-bulb/ 1 Link to comment Share on other sites More sharing options...
Tucano Posted August 28, 2019 Author Share Posted August 28, 2019 Seems to follow a pattern Link to comment Share on other sites More sharing options...
Kyle Communications Posted August 28, 2019 Share Posted August 28, 2019 Mick are you saying I maybe a bit pedantic at times ? Link to comment Share on other sites More sharing options...
Kyle Communications Posted August 28, 2019 Share Posted August 28, 2019 You can only afford a 915IS if you win the lotto anyway Link to comment Share on other sites More sharing options...
Litespeed Posted August 28, 2019 Share Posted August 28, 2019 Ouch, My old Alfas rang sodium exhaust valves, never ever heard of them having a issue. The price could be worse. My mate who builds Old school BMW M5 engines they are $ 400 each and you need 12, so $4800 just for exhaust side. And they are only going to get dearer. Link to comment Share on other sites More sharing options...
Downunder Posted August 28, 2019 Share Posted August 28, 2019 Are they the same size as 100 hp valves? Link to comment Share on other sites More sharing options...
M61A1 Posted August 28, 2019 Share Posted August 28, 2019 Mick are you saying I maybe a bit pedantic at times ? I was actually referring to the whole thread. I have seen it many times here and elsewhere....Someone asks a question, fifteen pages later, the question remains unanswered, but the OP's motive, viability, knowledge, and who knows what else have been questioned or derided. Link to comment Share on other sites More sharing options...
Tucano Posted August 29, 2019 Author Share Posted August 29, 2019 Experience has shown that the stock radiator will handle the load especially when installed with a duct - air dose not want to go through a Rotax radiator just because its hung in the breeze. My aircraft will also have the head load from the oil cooler added and the basic [very] calc's indicate it will be close to its limit at climb. Therefore a valve that better transfer heat into the head from the valve may help but is not a deal breaker. Hence the question at the start Link to comment Share on other sites More sharing options...
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