Russ P Posted September 5, 2013 Share Posted September 5, 2013 What can I do to stop a 4 stroke silencer vibrating loose? No matter how tight I tighten the locking nuts, they vibrate loose. Edited By Russ P on 05/09/2013 18:56:18 Quote Link to comment Share on other sites More sharing options...
Wingman Posted September 5, 2013 Share Posted September 5, 2013 I use epoxy as a locking compound and I also use it as gasket material for flange type silencer fittings - the heat involved seems to prevent it being a 'permanent solution' Quote Link to comment Share on other sites More sharing options...
Russ P Posted September 5, 2013 Author Share Posted September 5, 2013 I did think of using a silicone sealant but not sure it could cope with the high temperature. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted September 5, 2013 Share Posted September 5, 2013 I've had this problem Russ and if anyone comes up with a total solution I'd be pleased to hear about it. One thing that does help is to tighten it up when its hot rather than cold. I find that lasts for a month or so - then you have to do it again! TBH I've tried most of the selants - they don't seem to work for me. Most epoxies are only good to about 250C which is below the manifold temperature of the average 4 stroke. BEB Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted September 5, 2013 Share Posted September 5, 2013 hello russ from the ne...1 tech dept../not ...... take the exhaust off clean it with a wire brush and do the same with the head.....then ensure that it is dry....put it back together with a generous coat of clear silicone(aquarium type) is what i use.........when the flange is nipped up...run the rest around the nut and it should seal the joint and hold it in place....and should you need to break the joint-its easy to 'pick off' etc....i've used this method on 2/4st's for years with no problem's......... ken anderson ne..1 ..... tech dept.... Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 5, 2013 Share Posted September 5, 2013 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Ben B Posted September 5, 2013 Share Posted September 5, 2013 JB weld might be the answer. Good to 600F for 10 minutes (315 degrees C). Otherwise can you not use two thin lock-nuts to really nip it up tight? Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted September 6, 2013 Share Posted September 6, 2013 I'm with Percy on this one. Silencers coming loose just haven't ever been a problem on any of my 4 strokes - but I do always balance my props and avoid cheap and nasty spinners. I always screw the header pipe into the head until the thread botttoms - then unscrew (less than a turn) to align it with the desired angle so that the maximum number of threads are in use and do the locknut up as tight as possible with a correctly fitting spanner (not an adjustable). Quote Link to comment Share on other sites More sharing options...
Russ P Posted September 6, 2013 Author Share Posted September 6, 2013 Thanks for all of the ideas. I,ll start with the easiest, check the prop. Thanks again. Quote Link to comment Share on other sites More sharing options...
Greybeard Posted September 6, 2013 Share Posted September 6, 2013 I use silicone sealant on my OS 4 stroke engine exhausts, something that they recommend. It works well and is easy to dismantle and clean off. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted September 6, 2013 Share Posted September 6, 2013 Well, I had an OS91FS, I always balance my props, for this I balanced the spinner as well. Both prop and spinner where "top end" components. The spinner for example being a Tru-Turn job I imported from the States. I tried everything with that engine. Sillicone, epoxy, lock nuts, JB weld, exhaust cement, copperbond; I tried different exhaust geometries from straight out the box standard to complex arrangements using flexipipes or knuckles - you name it I tried it. In my oopnion the vibration was far from excessive - less than on most engines - but could I keep an exhaust on that engine for more than half a dozen flights? Could I heck! I tried a new header pipe, I examined the outlet threads with a magifiying glass - all looked well. But if I just installed the prop it would come off after 5 minutes. If I installed hot - as I said I might get half a dozen or so flights before it came off. I've never had this problem - certainly not to this degree - with other engines. But it can happen and if it hasn't happened to you, I can only say that I'd add a "yet" to the end of your sentence! BEB Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 6, 2013 Share Posted September 6, 2013 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Rick Tee Posted September 7, 2013 Share Posted September 7, 2013 I use high temp oil resistant silicone or acrylic sealer, the bath room type doesn't seem to tolerate the heat or oil. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted September 7, 2013 Share Posted September 7, 2013 I always add a few layers of PTFE tape (the sort used by plumbers) to the manifold thread before screwing the manifold into the head (right in as Martin Harris sez...) & fitting the silencer. Use a correctly fitting spanner to nip them up.....job done!! I've never had one come loose......yet!! (OK.... BEB?? ) Quote Link to comment Share on other sites More sharing options...
Doug Ireland Posted September 7, 2013 Share Posted September 7, 2013 Posted by Steve Hargreaves - Moderator on 07/09/2013 11:25:25: I always add a few layers of PTFE tape (the sort used by plumbers) to the manifold thread before screwing the manifold into the head (right in as Martin Harris sez...) & fitting the silencer. Use a correctly fitting spanner to nip them up.....job done!! I've never had one come loose......yet!! (OK.... BEB?? ) Something to be wary of when using thread tape. Don't use too much or you can/will crack the head or silencer! Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted September 11, 2013 Share Posted September 11, 2013 It could be just an out of balance engine . I have seen it in the past ,two identical engines but one will vibrate really bad. I have two YS 140 and one is as smooth as can be and the other vibrates quite a lot. It hasn't shaken the exhaust off yet bit is still noticably more shaky than the other. I dont use any sealer ,tape or stuff on the exhaust. I just insert the header as far as it will go , screw back to align then tighten. Run engine up to temp and re-tighten while hot, as said previously ,using a good quality spanner . Quote Link to comment Share on other sites More sharing options...
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