procharger Posted October 24, 2015 Report Posted October 24, 2015 Can I buy all o rings for top end for one cylinder or do I have to buy for all four? I got a leak somewhere. Who has them? thanks
Tom Baker Posted October 24, 2015 Report Posted October 24, 2015 Can I buy all o rings for top end for one cylinder or do I have to buy for all four? I got a leak somewhere. Who has them? thanks What kind of leak, and where do you think it is coming from.
procharger Posted October 24, 2015 Author Report Posted October 24, 2015 not sure had head and cyl. redone about 125 hours ago because of a leak but it appears to be coming between cyl. and head again at bottom not sure I have cleaned it several times to try to find it but can't seem to pinpoint where it is, all the wind blowing through cowl spreads it around, not bad but a little kooks like a lot.
Tom Baker Posted October 24, 2015 Report Posted October 24, 2015 I recently removed and reinstalled the heads on a 912 to clean the exhaust valves. In talking with Brett at LEAF there is a service instruction that covers a leak that appears to be coming from the cylinder head, but it is coming from the stud in the case and traveling through the passage in the cylinder. He said if you have it apart it should be done, along with replacing all the seals. For all 4 cylinders it was over $300 in parts, but that did include the cylinder alignment tool. http://legacy.rotaxowner.com/si_tb_info/serviceinfo/si-912i-006r1.pdf I installed the special seals when I re-assembled the engine.
FredG Posted October 25, 2015 Report Posted October 25, 2015 Tom, on the 912, where does the oil come from that gets into the void where the case stud is located (what is the source of that oil)? Procharger - what year is your engine? Thanks, Fred
Anticept Posted October 25, 2015 Report Posted October 25, 2015 Those holes have rods that are similar to through-bolts for opposing cylinders in lycomings and continentals. What they do, is help mate the main bearings snugly once torqued. I can't exactly remember how they were fitted, but I am pretty sure there are rods inside the case, with a female-female threaded sockets on each end, in which the rods that bolt the cylinder on will thread into. Oil can get by from crankcase pressure. The gasket/o-ring prevents the oil from getting past the stud and outside. This is why I was asking for photos because that's where I was headed :-)
Tom Baker Posted October 25, 2015 Report Posted October 25, 2015 Those holes have rods that are similar to through-bolts for opposing cylinders in lycomings and continentals. What they do, is help mate the main bearings snugly once torqued. I can't exactly remember how they were fitted, but I am pretty sure there are rods inside the case, with a female-female threaded sockets on each end, in which the rods that bolt the cylinder on will thread into. Oil can get by from crankcase pressure. The gasket/o-ring prevents the oil from getting past the stud and outside. This is why I was asking for photos because that's where I was headed :-) 2 of the studs per cylinder have inserts in the case and the other 2 just thread into the case. The latter two are the ones that leak. Fred, The area in the case that the stud is threaded into must be open to inside the crankcase where the oil lives.
Anticept Posted October 25, 2015 Report Posted October 25, 2015 Yeah the service bulletin says which of them needs the seals.
procharger Posted October 25, 2015 Author Report Posted October 25, 2015 My leak shows up at bottom between head and cylinder drops of oil on fins on both sides of push rod tubes mainly. I have cleaned area several times and then fly hard for 30 min. or so and pull cowls and don't see anything, that's the weird part then next time I will see signs of oil so not sure what is going on, usually when it leaks there will be some oil on front ex. pipe that has dripped down anyone else seen this on there engine?? Does my engine have any seal on studs now? Mine Ct is 2007 about 1200 hours.
N456TS Posted October 25, 2015 Report Posted October 25, 2015 So, after you fly there is nothing, but the next day, oil shows up? You could spray some leak detection/tracing powder and check for leaks the next day. It's good to know exactly where the leak is before diving in.
Tom Baker Posted October 25, 2015 Report Posted October 25, 2015 No seals on the studs from the factory for your year model. The problem showed up with the new heavy case in mid 2006. There is also a serial number break where it takes a different seal. If you have the head loose you should also replace the cylinder base o-ring, because it will relax and not seal right when tightened back down. It is kind of a pain, because you need to strip the engine down far enough to remove the top air shroud.
procharger Posted October 25, 2015 Author Report Posted October 25, 2015 Plane was flown for hour yesterday i went back this afternoon and no oil showing anywhere this has happened before kind of crazy it may take more than an hour for it to show not sure. My serial # is 5.648.277 its the front left cylinder.
Anticept Posted October 26, 2015 Report Posted October 26, 2015 Keep an eye on it. When you see it, take photos.
FastEddieB Posted October 26, 2015 Report Posted October 26, 2015 You could spray some leak detection/tracing powder and check for leaks the next day. Desenex or equivalent spray foot powder works well.
procharger Posted October 26, 2015 Author Report Posted October 26, 2015 thanks for all suggestions I might try the powder next.
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