ave8rr Posted February 5, 2013 Share Posted February 5, 2013 One of the easiest things to do each day before a flight is do a pull-through, it's not a 100% fool prof analysis but it's not a bad pre-flight progamme ... if there is a "soft one" stay on the ground and check out why.Cheers Vev Vev, that is exactly how we found the "soft" cylinder in our J160 at 160 hours. Link to comment Share on other sites More sharing options...
Guernsey Posted February 5, 2013 Share Posted February 5, 2013 One of the easiest things to do each day before a flight is do a pull-through, it's not a 100% fool prof analysis but it's not a bad pre-flight progamme ... if there is a "soft one" stay on the ground and check out why.Cheers Vev This is exactly what my wife does to me before we undertake any sort of aerial activity in the bedroom. (leaping from chandeliers etc ). Alan. 2 Link to comment Share on other sites More sharing options...
damkia Posted February 5, 2013 Share Posted February 5, 2013 I would never put a Jab into a Tornado, just asking for trouble. "Asking for trouble" would be a Jab powered Helicopter... 1 1 Link to comment Share on other sites More sharing options...
Vev Posted February 5, 2013 Share Posted February 5, 2013 Vev, that is exactly how we found the "soft" cylinder in our J160 at 160 hours. Good stuff ave8rr In my experience I have found the pull-thru very useful and a part of my pre-flight safety procedure .. whilst it won't tell you what is wrong it allows you to investigate. 9/10 times pulling the top end off a soft pot will save your wallet heaps.. it will also, in all probability, prevent a catastrophic failure in flight. Cheers Vev Link to comment Share on other sites More sharing options...
MarcK Posted February 5, 2013 Author Share Posted February 5, 2013 In my opinion this thread has been great and provided me with a heap of things to think over. Thanks to all that took the time to respond and provide there experiences and opinions. A good bit of heated debate to. I look forward to a thread that I am qualified to answer. Marc Link to comment Share on other sites More sharing options...
Ultralights Posted February 5, 2013 Share Posted February 5, 2013 "Asking for trouble" would be a Jab powered Helicopter... like this? Link to comment Share on other sites More sharing options...
dazza 38 Posted February 5, 2013 Share Posted February 5, 2013 One of the easiest things to do each day before a flight is do a pull-through, it's not a 100% fool prof analysis but it's not a bad pre-flight progamme ... if there is a "soft one" stay on the ground and check out why.Cheers Vev We found a soft cylinder as well in a J160.It has only flown from the factory to Boonah.Not good. Link to comment Share on other sites More sharing options...
Gnarly Gnu Posted February 5, 2013 Share Posted February 5, 2013 Can anyone indicate honestly, either their own, or someone they know, and can prove, that they have a 2200 engine that made 1000 hour top end without EVER having a problem, ie, never being opened up for anything more than normal scheduled maint, and ignoring minor issues. I dont want to hear that yours made it, but you replaced the heads at 220, and 600, and top ended at 800... I want to know if ANY jab 2200 engines made it all the way. Yep, 2200 first opened at 1000 hours and pristine inside. Was running great also. A surprise to many but it can happen... 2 Link to comment Share on other sites More sharing options...
planedriver Posted February 5, 2013 Share Posted February 5, 2013 Thats great to hear, hope theres many more with a similar post . I love Jabbys, but always have little niggle at the back of my mind as to whether the fan will keep doing its job? Link to comment Share on other sites More sharing options...
cooperplace Posted February 5, 2013 Share Posted February 5, 2013 One of the easiest things to do each day before a flight is do a pull-through, it's not a 100% fool prof analysis but it's not a bad pre-flight progamme ... if there is a "soft one" stay on the ground and check out why.Cheers Vev thank you I'll make sure that's part of my pre-flight. Link to comment Share on other sites More sharing options...
Keenaviator Posted February 5, 2013 Share Posted February 5, 2013 Andy,What fantasy dream are you trying to live out with that question? I do know a few that have made it all the way, ..................to the chain at the bottom of a boat anchor. Can't help you mate on your question don't know of any in my area Alf Unfortunately Alf we don't see much of you in our area! Sandra Lewis' and Nelson Smith's made it to over 1000 hours with routine servicing. I'm pretty sure Anthony Morrison had a good run with several in his school. My serial number 049 did between 500 and 600 hours without failure. Link to comment Share on other sites More sharing options...
Thirsty Posted February 5, 2013 Share Posted February 5, 2013 If you didn't fly every time you did a pull through and found a soft pot you'd never fly! Link to comment Share on other sites More sharing options...
David Isaac Posted February 5, 2013 Share Posted February 5, 2013 If you didn't fly every time you did a pull through and found a soft pot you'd never fly! I am curious, are you talking about Jab engines in particular or all engines ... Just to clarify from my perspective ... Because of known Jab issues, I would not fly a jab engine with a soft pot, but depending on how soft, I may fly a Lyc, Cont or Gypsy, but would notify the soft pot to the LAME or make a note in the maintenance release. I think I know engines enough to make the judgement call on 'how soft' though. If it was substantially soft, I would be concerned, run the engine to temp, then stop it and check how soft after running up to temp. Link to comment Share on other sites More sharing options...
motzartmerv Posted February 5, 2013 Share Posted February 5, 2013 How many pull through's for a 4 cylinder? 4 or 8? Link to comment Share on other sites More sharing options...
Thirsty Posted February 5, 2013 Share Posted February 5, 2013 David: Talking about Jab engines. We operate Jabs in the flying school where I work and I own a J160. We often get soft pots and there is no way we could pull heads off every time that happens. Sometimes a hard run will return compression and sometimes not. We just have to take our chances. Andy: we pull through 8 times. Link to comment Share on other sites More sharing options...
David Isaac Posted February 5, 2013 Share Posted February 5, 2013 Same here call me excessive, I pull through at least 8 and sometimes more if I have a concern. I will also run an a engine up if in doubt and recheck. I know pilots that don't pull through at all and wouldn't have a clue what a 'soft pot' is. But please be careful pulling through Magneto equipped engines. Treat the prop as live at all times. Jabs are not mag equipped and can lead to lazy practices if you then pull through a Mag equipped engine. If you pull an engine through the compression stroke slowly you can hear any valve leak through the exhaust or inlet if the ambient is quiet, but the act of pulling slowly is VERY dangerous on mag equipped engines. 3 Link to comment Share on other sites More sharing options...
Thirsty Posted February 5, 2013 Share Posted February 5, 2013 And instead of instantly pulling heads off it's a lot quicker to do a quick leakdown (if you have the gear) and find out what the problem is. Might be rings in which case go fly and give it a good hard run, actually a good hard run often fixes most problems with these engines we've found except if a valve is about to let go :) 1 1 Link to comment Share on other sites More sharing options...
Vev Posted February 5, 2013 Share Posted February 5, 2013 David: Talking about Jab engines. We operate Jabs in the flying school where I work and I own a J160. We often get soft pots and there is no way we could pull heads off every time that happens. Sometimes a hard run will return compression and sometimes not. We just have to take our chances. Hi thirsty, I don't think one needs to pull a head off every time you find a soft pot but you do need to investigate why. In the example you have used about compression going up after a hard run, it could still mean there is a serious problem. I have seen on a number of Jab engines rings stuck in their groves owing to carbon build up, often from burnt oil as opposed to blow by from combustion. The burnt oil can also often be seen on the underside of the piston crown, which is a sure sign of over heating. If a stuck ring is left unchecked it can cause ring breakage, bore scoring and piston ring land break up and of course an engine failure. I still maintain you need to find out what is wrong and simply not take chances. Cheers Vev 1 Link to comment Share on other sites More sharing options...
Sapphire Posted February 5, 2013 Share Posted February 5, 2013 New engines where the rings havn't been run in and cold engines is no time to check final compression. New engines that don't run in need to have the bore deglazed properly and new rings put in. Link to comment Share on other sites More sharing options...
Thirsty Posted February 5, 2013 Share Posted February 5, 2013 We understand all that Vev but over the years (17 or so operating these engines) we've not had real issues like that. We mostly have through bolt failures and the odd dropped valve. Again, if we had to spend the time researching and fixing low compressions on these engines we'd never fly and that's not an exaggeration. Link to comment Share on other sites More sharing options...
Gentreau Posted February 5, 2013 Share Posted February 5, 2013 All sounds incredibly complex and subjective for an engine manufactured in the 21st century ! . 1 Link to comment Share on other sites More sharing options...
Sapphire Posted February 5, 2013 Share Posted February 5, 2013 All sounds incredibly complex and subjective for an engine manufactured in the 21st century !. The Continental 0-200 was designed in the 1940's and new engine designs are only a rough copy. 60 over 80 in a leakdown test is considered min. compression and lower copression means less power but not necessarily engine failure. Link to comment Share on other sites More sharing options...
Gentreau Posted February 5, 2013 Share Posted February 5, 2013 So we're still using 1940's technology and maintenence routines in 2013 ? I would have thought we've had time to improve somewhat over the last 70 years ! . Link to comment Share on other sites More sharing options...
motzartmerv Posted February 5, 2013 Share Posted February 5, 2013 No no. The 40's design is good, its the more modern incarnations that are causing the problems..;) 1 Link to comment Share on other sites More sharing options...
alf jessup Posted February 6, 2013 Share Posted February 6, 2013 Unfortunately Alf we don't see much of you in our area!Sandra Lewis' and Nelson Smith's made it to over 1000 hours with routine servicing. I'm pretty sure Anthony Morrison had a good run with several in his school. My serial number 049 did between 500 and 600 hours without failure. Keeny, Nope I do not see much of you boys down the Valley way. That is excellent news on Sandra's, Nelsons, Anthonys and yours, how many down there have had trouble. I know Barry had a through bolt then later on a valve go. one of edges up here had to re valved and ringed at 380 hrs, Tony P's LSA had nothing but trouble when he had it. The Sale boys Ben and Darryl have had a good run with theirs but have made a few changes from standard, fine finned heads and changed back to solid lifters, I don't think Darren has had much go wrong with your old Corby (I am presuming this is Laurie I am talking too) That is the thing we only ever hear over the grapevine of grumblings and not the good things. I don't have an issue with them as I have a few hrs behind them, I just would not be comfortable taking it over the country I take my rotax over at times. Alf Link to comment Share on other sites More sharing options...
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