Ted Khinsoe Posted January 10, 2020 Share Posted January 10, 2020 looking for advice how to loosen a stuck piston ring. Acquired a used Enya 53 four stroke. Ring looks ok but is stuck solid. Tried soaking in petrol, methanol, heating in oven without any joy. I’m keen not to destroy the ring if possible. Ted Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted January 10, 2020 Share Posted January 10, 2020 Hello Ted . It should come out but it takes time .I have done many over the years and only occasionally have I been beaten . A good soak in some "Plus Gas " really helps . Other penetrating oils like WD 40 are a waste of time . Some heat will also help but you will need more that a oven . I have used a small blow lamp but care needs to be taken as overheating will ruin the temper of the ring . Heat the whole piston gently from the crown and allow the heat to travel down past the ring .If this fails to loosen it then soak over night in Plus Gas and try again . Then try prying the gap of the ring apart very gently with a Jeweler screwdriver sharpened to a sharp edge . Be VERY gentle or the ring can break . Once it starts to move push it back in then pry it out of the slot again and again ,gradually it will free . Keep applying plus gas to the area . If it does break then a new / replacement ring is available on ebay for about £10 Good luck and let us know how you get on . E.D. Quote Link to comment Share on other sites More sharing options...
Ted Khinsoe Posted January 11, 2020 Author Share Posted January 11, 2020 Thanks ED. Thought that may be the case I was hoping to avoid mechanical force if possible. I thought about applying the blowtorch but was concerned about the temper. I think the previous owner was a castor fan Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 11, 2020 Share Posted January 11, 2020 Try Freezing Then warming Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted January 11, 2020 Share Posted January 11, 2020 Posted by Denis Watkins on 11/01/2020 09:23:12: Try Freezing Then warming Good point Dennis. The contraction and then expansion of the alloy piston will be greater than the iron piston ring and may compress the varnish/gum etc that's holding the piston in its groove . Soaking it before hand in plus gas may soften the varnish /gum and make the effect more pronounced . Quote Link to comment Share on other sites More sharing options...
Jon H Posted January 11, 2020 Share Posted January 11, 2020 I cant disagree with anything thats been said. The only thing you need to try and decide is what is holding the ring. If its castor then by all means try and rescue it. At work i have used drops of methanol and a sharp tool i have to try and pry the ring gap open but that only works with oil residue. If you think the ring has rusted into the slot then you might do better to just go nuts and take it out in pieces as a rusty ring will need to be replaced anyway. This was the case on my enya 53 and i asked the chap on ebay to make me a slightly oversize replacement as i had to do some surgery to the liner with a brush hone to take out some light rust pitting. Quote Link to comment Share on other sites More sharing options...
Richard Wills 2 Posted January 11, 2020 Share Posted January 11, 2020 If you have or know anyone with an ultrasonic cleaner, popping the piston in there for half an hour will do the trick. Quote Link to comment Share on other sites More sharing options...
Ted Khinsoe Posted January 12, 2020 Author Share Posted January 12, 2020 Thanks for the suggestions I’ll let you know how I get on. Currently building a SE5a so the engine work will be done while waiting for paint to dry. Quote Link to comment Share on other sites More sharing options...
Wilco Wingco Posted January 20, 2020 Share Posted January 20, 2020 Does anybody know how to "release" a suspected stuck piston ring without stripping the engine?. I have replaced a broken valve spring and reset the gaps but still very little compression. Wide open throttle makes no difference. If I inject a little fuel into the cylinder the compression improves but not brilliant. The bore has no sign of ware and there seems to be no leaks round the valves so the only thing I can think of is stuck ring?. I have not tried running the engine yet so maybe that will improve the situation??. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 20, 2020 Share Posted January 20, 2020 Usually Wilco The piston ring does its thing with the motor running. You can't turn it over fast enough by hand I have 4 strokes I can easily turn over by one finger cold But thrash around the sky when hot Quote Link to comment Share on other sites More sharing options...
Jon H Posted January 20, 2020 Share Posted January 20, 2020 If its not rusty then it sounds like it needs an italian tune up. Go a good inch smaller than your normal prop, fire it up, full chat as lean as it will go then throttle back by about 500-1000 rpm. Leave it there for a little while, back up to full power, idle, rev up, generally slap it around with a decent number of accelerations from idle to full power and plenty of revs. After a few minutes of that it should be right as rain. If not, slap a new ring in it and do it again Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted January 20, 2020 Share Posted January 20, 2020 As suggested an "Italian tune up" may do the trick also as said "If its not rusty " If engine has been stored for a long period and there's a chance it may be rusty then running it with a stuck piston ring may do damage to the liner. Quote Link to comment Share on other sites More sharing options...
Wilco Wingco Posted January 20, 2020 Share Posted January 20, 2020 When I had the head off to replace the valve spring the bore looked fine, don't know if I would see any signs of rust? Not sure how long the engine has not been run, bought at a swap meet, so I will risk the "Italian Tune up" and see what happens. Thanks chaps, watch this space. Quote Link to comment Share on other sites More sharing options...
Jon H Posted January 20, 2020 Share Posted January 20, 2020 Posted by Wilco Wingco on 20/01/2020 13:48:05: When I had the head off to replace the valve spring the bore looked fine, don't know if I would see any signs of rust? Not sure how long the engine has not been run, bought at a swap meet, so I will risk the "Italian Tune up" and see what happens. Thanks chaps, watch this space. If the ring is rusty you will likely see rust coloured oil in the bore as you move the piston up and down. If there is any suspicion of rust on the ring or bearings then its worth stripping it down. Slightly noisy bearings should be replaced immediately as eventually the cage will fail and metal fragments will fall into the crankcase. This makes a right mess so if you are in any doubt take it to bits and have a good look. Quote Link to comment Share on other sites More sharing options...
Wilco Wingco Posted January 20, 2020 Share Posted January 20, 2020 Thanks Jon. I wiped the inside of the bore with a tissue before re-oiling it and replacing the head, no sign of rust at all. The bearings are silent as the grave so I will give it a run soon and see if that improves things. Assuming it will run with little compression???. Quote Link to comment Share on other sites More sharing options...
Barryorbik Posted January 20, 2020 Share Posted January 20, 2020 Not tried it myself but a few of the even older members at our club swear by diesel fuel (the sort you put in your car not the free flight stuff!) for freeing badly stuck piston rings. Apparently you may have to leave the piston in the stuff for a few days but it is supposed to clean the gum or oil off really well. Might be wrth a try. Barry Quote Link to comment Share on other sites More sharing options...
Wilco Wingco Posted February 7, 2020 Share Posted February 7, 2020 Just run the engine with suspected stuck ring. What can I say. It started first flick with a chicken stick and ran like a good un. It now has some compression when I turn it over by hand, lets hope it will improve with more running. Looks like the old "Italian Tuneup" worked. Quote Link to comment Share on other sites More sharing options...
Ted Khinsoe Posted February 19, 2020 Author Share Posted February 19, 2020 Just to follow up on my Enya53. I managed to move the ring over 1/3 circumference but the remainder was solid and the ring broke. I replaced it with a spare I had for an OS 56alpha (all dimensions were identical!) and it’s running well. Thanks for the suggestions. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted February 19, 2020 Share Posted February 19, 2020 Glad you sorted it Ted. Its a very slow process to get a ring un-stuck and they unfortunately sometimes break just when you thought you were winning . Worth knowing that the OS ring is the same size . E.D. Quote Link to comment Share on other sites More sharing options...
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