Steve Hargreaves - Moderator Posted May 13, 2007 Share Posted May 13, 2007 Does it matter if you put a piece of fuel tube over the crankcase breather of a 4-stoke motor? I want to route the pipe to outside the cowl so it doesn't spray oil mist around the inside of said cowl but something makes me think that maybe I shouldn't....The pipe would need to be about 6" long & the motor is mounted inverted...Any advise?? Quote Link to comment Share on other sites More sharing options...
Bladerunner Posted May 14, 2007 Share Posted May 14, 2007 Steve, that should work fine. Most folks use some tubing on the breather to help duct the oil. I use 4-8 inch tube on my 4 strokers, and no problems. However, make it as short as possible, and follow the manufacturer recommendations when provided. Some of the newer engines feed the breather to the carb, thus reducing the oil residue. Quote Link to comment Share on other sites More sharing options...
Chris Dickens Posted May 14, 2007 Share Posted May 14, 2007 SteveIf you are just going to add a length of fuel tubing to the breather nipple then 2" would be the maximum that will work before you start to get potential running problems. The reason being that any greater length will cause too much back pressure. If you need to extenfd further then feed a short length (less than 1" ) of pipe from the nipple into a tube of at least 1/4" (5mm) diameter and you should then have no problems.Chris Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 14, 2007 Author Share Posted May 14, 2007 Aaaarrrghh....two different answers to the same question!!!Now what do I do???? Quote Link to comment Share on other sites More sharing options...
winchweight Posted May 14, 2007 Share Posted May 14, 2007 My ASP65FS had about 4" and ran fine. Until the crash that is....... :( (Nothing to do with the engine, more to do with the hamfisted clown flying it!) Quote Link to comment Share on other sites More sharing options...
Bladerunner Posted May 14, 2007 Share Posted May 14, 2007 Just run it. You should'nt have any serious problems. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 14, 2007 Author Share Posted May 14, 2007 Bladerunner...you think like me!!!!I shall give it a go & see wot happens!! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 15, 2007 Share Posted May 15, 2007 I thought back pressure was only a problem with an enclosed sump containing oil ?Hence the provision of a breather system on your motor car or lawnmower (assuming you've not gone all 'lectric with them as well!) Quote Link to comment Share on other sites More sharing options...
Roger Auker Posted May 15, 2007 Share Posted May 15, 2007 I have an RCV 91 CD installed in a World Models Mustang 60. The crankcase breather issue was a concern to me as I did not want to have the excess oil on the plane. Whilst running the engine in I connected a long (like 1.3m) length of fuel tube and had it "dangling in the breeze". When this worked fine and deposited the oil aft of the tail, I then routed the fuel tube in the fuselage and exited near the tailwheel. I know the instructions said a maximum of 6", but the system works fine and despite very high ambient temperatures as we approach summer, the engine has never missed a beat. By high temperatures I mean 39° and that is by 10:00 in the morning !! It does get a lot hotter in full summer !! By the way I live, work and fly in Dubai. I can supply photos if you are interested. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 15, 2007 Author Share Posted May 15, 2007 I think the issue is one of pressure equalisation....obviously as the motor runs the crankcase volume will change as the piston moves up & down....the breather is to allow air to rush in & out as needed....obviously as the air rushes out it will take some oil mist with it & potentially block the tube. That said the pumping force will be quite significant compared to a small plug of oil so like Bladerunner sez it shouldn't cause any problems.... Quote Link to comment Share on other sites More sharing options...
Roger Auker Posted May 15, 2007 Share Posted May 15, 2007 Forgot to mention in my earlier post, I do hang the model nose up after the flying session for a couple of days to help the oil drain from the fuel tube. No problems at all and the engine is a real powerhouse. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 15, 2007 Share Posted May 15, 2007 Thanks Doesn't it make you wonder who is the expert that stipulates what you can & can't do with their engines (the manufacturers /designers etc ) when all along it does't seem to really matter .Who really knows what it's like to be in a crankcase What an ever( fast ) changing environment eh ? Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 15, 2007 Author Share Posted May 15, 2007 Of all the places I've ever wanted to be Myron, a crankcase is not one of them!!!!!! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 15, 2007 Share Posted May 15, 2007 Nice one Steve You've obviously never been in a cylinder head Luxury !!!!!! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 15, 2007 Share Posted May 15, 2007 PS Ijust remembered I did go into a crankcase years ago changing bits on an oil rig engine I think it was called a SNACME if my memory serves me correctly More useless information he said .Do you thin k a "nostalgia " topic/thread or whatever would be of popular appeal on this great website I really enjoy remi-remmin remni Goig back ie going back ? Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted May 15, 2007 Author Share Posted May 15, 2007 Would that be an aluminium cylinder head??? Luxury.....when I wor a lad we was glad to even get to SEE a cast iron cylinder head......oh dear this thread seems to have degenerated into a Monty Python sketch!!!I do remember seeing a picture of a marine diesel being decoked.....three blokes with scrapers & brooms stood on top of one of the pistons!!! Now thats big!!! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 15, 2007 Share Posted May 15, 2007 Before I remember I was talking about having a breather (I'd nearly forgotten )We never 'ad brooms We had to lick off carbon w'it toung Aye .As for scrapers I won't (daren't) tell you what I had to use but it's a good job no-one was looking through the inlet or exhaust ports.You must be a lot younger than me 'cos i remember cast iron well.It was the only thing I couldn't solder together aye them wer't days Long before breathers were invented We used to----Hang on I'm definately going off the subject & someone will complain ?By the way cast iron is still difficult to stick back together(getting back to engineering)Or is there a new DEVRON product on the market Do you remember the name We used it on cylinder walls to fill cracks & IT WORKED Yes I remember my spells in the odd crankcase /head Them we're t' days Eh! Quote Link to comment Share on other sites More sharing options...
Dave Harbour Posted May 21, 2007 Share Posted May 21, 2007 In the instructions for my TT54FS it suggests connecting the breather to a 2 1/2" length of brass tubing strapped to the exhaust muffler bent at 45 deg at the end so the oil is blown away with the axhaust gasses, works fine. Quote Link to comment Share on other sites More sharing options...
Aslan Posted May 21, 2007 Share Posted May 21, 2007 Tongue?????|Yeou were lucky.....We adint got one o'those..... Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 21, 2007 Share Posted May 21, 2007 After 12 cylinders I 'ad no tongue either /Call that luck ??? Try licking just 1 and see how t' mouth feels- by gum ! Quote Link to comment Share on other sites More sharing options...
Aslan Posted May 22, 2007 Share Posted May 22, 2007 Mouth!!!!!.....Heaven....had t'use eyeball,and it were bugger to get back in after.:):) Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 22, 2007 Share Posted May 22, 2007 You've never lived ! You had an eye !? We had no equipment like a glass eye to help us . We had to use t' lid to polish up t' piston tops & eyebrows to get a really good shine on t' crown .It never blinkin' worked I don't think -but then again we worked in the dark confines of t'moving parts of t' engine where no-one checked our wirk Weworked 24 hour shifts 8 days a week if i remember correctly .My co worker once had a day off 'cos his 'er indoors said he had a serious headache & to prove it she had to produce his death certificate .You tell young people that .They wouldn't believe it .We need more breathers (going back to the thread )and should only do jobs in engines for a maximum of 7 days a week. Quote Link to comment Share on other sites More sharing options...
Malcolm Fisher Posted May 22, 2007 Share Posted May 22, 2007 I can remember casting cylinders for ships diesels - three foot ID and about six foot stroke an we 'ad to decore 'em wiv bare 'ands...As fo days orf - ferget it. Quote Link to comment Share on other sites More sharing options...
Aslan Posted May 22, 2007 Share Posted May 22, 2007 Only 7 days in a week....you reeely were lucky.We 'ad 7 years in our week,and no ruddy eyebrows.Comical it were...Comical I tell thee.Would have paid(if we 'ad any dabs)to decore wiv bare 'ands....lugsherry,pure bliss...'ad t'use scrotum in my day..if ye could find one. Quote Link to comment Share on other sites More sharing options...
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