Rich Griff Posted June 28, 2021 Share Posted June 28, 2021 Ovens, a chap placed cylinder head and barrel in oven to cure the paint whilst she was out. Head was ok as it was right way up, so nothing "fell out". The cylinder was right way up also, resting on the cylinder liner bases...... The cylinder alloy casting with the fins on "fell down "... He just turn it upsidedown and waited. 1 Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 28, 2021 Share Posted June 28, 2021 I dont want to be all nanny state about it but i dont recommend putting a carcinogen in your oven and cooking it. 1 Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 28, 2021 Author Share Posted June 28, 2021 Sorry Rich need the needle for cosmetic reasons. Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 28, 2021 Author Share Posted June 28, 2021 Wondering if my chums in the motor bike repair shop have a bead blasting facility which may clean the last of the crud off the head. Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted June 28, 2021 Share Posted June 28, 2021 Ovens, a chap placed cylinder head and barrel in oven to cure the paint whilst she was out. Head was ok as it was right way up, so nothing "fell out". The cylinder was right way up also, resting on the cylinder liner bases...... The cylinder alloy casting with the fins on "fell down "... He just turn it upsidedown and waited. Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted June 28, 2021 Share Posted June 28, 2021 To get the head find really clean I used a brass wire brush. Yep I understand about the spray bar unit to keep the look, but I can pay for yours and send you my bent/ broken one. It will look athletic on the dummy engine, as if it was a runing engine, and then mine can/will run again. I can repair mine as I have some brass nuts, but a servicable one would be better. What do you think ? Quote Link to comment Share on other sites More sharing options...
Martin Arnold 1 Posted June 28, 2021 Share Posted June 28, 2021 (edited) Have had great success cleaning glow motors using Ethylene Glycol antifreeze (the old blue stuff) in a hot slow cooker for few hours, the gunk just brushes of with a toothbrush afterwards and it doesn't harm the original finish. Here is a before and after treatment, this had about 5 hours in the pot. Edited June 28, 2021 by Martin Arnold 1 Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted June 28, 2021 Share Posted June 28, 2021 (edited) I have heard of this method but not got round to trying it yet. 5 hours on a low heat, mmmmm how much gas or electricity is that I wonder, but will give it a go, maybe on the next one. Will have to think of a good excuse to give the wife a day off so I can try this.... Edited June 28, 2021 by Rich Griff Quote Link to comment Share on other sites More sharing options...
Martin Arnold 1 Posted June 28, 2021 Share Posted June 28, 2021 (edited) Will hasten add i do not use this for cooking !!! And not inside the house !! I run it in my workshop/garage on high heat, the antifreeze reaches about 130c from memory and the vapors are rather unpleasant, but as you can see the results are impressive it left that well caked up silencer looking like new with no abrasive used at all just a good scrubbing with a tooth brush three or four times during the process. As you can see there is no discolouring of the part either, apparently this is because the antifreeze is used without any dilution, if it is diluted the part can darken. Edited June 28, 2021 by Martin Arnold 1 Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 29, 2021 Share Posted June 29, 2021 (edited) 13 hours ago, Martin Arnold 1 said: Have had great success cleaning glow motors using Ethylene Glycol antifreeze (the old blue stuff) in a hot slow cooker for few hours, the gunk just brushes of with a toothbrush afterwards and it doesn't harm the original finish. Here is a before and after treatment, this had about 5 hours in the pot. That seems to work a treat, but...again, to be all nanny state, ethelene glycol is highly flammable so heating it could be rather precarious. it will also gas off as you mention causing a few issues should you happen to breathe the vapours or get it in your eyes. I am not saying it cant be used, just that many of the suggestions so far are potentially very hazardous and the end result of a shiny exhaust is not really worth it given the fact that it will only get oily again the next time you run the engine. Ultimately this is why i say not to bother with it. Edited June 29, 2021 by Jon - Laser Engines 1 Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 29, 2021 Author Share Posted June 29, 2021 Rich PM sent regarding needle. Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted June 30, 2021 Share Posted June 30, 2021 What would worry me using ethlylene glycol is it’s toxicity. If you are boiling it you may well be breathing the fumes which are poisonous. Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted June 30, 2021 Share Posted June 30, 2021 Hi Andy, pm just sent... Quote Link to comment Share on other sites More sharing options...
Andy J Posted July 5, 2021 Author Share Posted July 5, 2021 Just reassembled the engine and it feels as though it has little compression. Was this standard for the small Merco's given the piston has no ring? Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted July 5, 2021 Share Posted July 5, 2021 (edited) Lots of engines do not have a piston ring, including compression ignition diesels. You made and fitted a head gasket ? My 35 has very good compression with a home made gasket. You say the alloy prop driver hub is no t locked to the crankshaft via a taper, key, splines or d drive, which sounds very odd. Even a Cox 049 has a means via splines. The DC sabre diesel 1 1/2 cc has a taper and my magnum gp40 glow has a d drive... These engines are a bit small for a key... The 29, 35 and 61 merco I have use a split/slotted collet that is a taper fit into the alloy prop driver hub... The 29 and 35 are ringless and have good compression even though they have some wear and etching due to poor storage in thier former lives... Are you sure the collet is not stuck in the alloy hub ? The split/slotted collet is effectively clamped to the crankshaft due to the slit and taper fit of the drive hub and nut. Good luck with your "electrification" making the merco a "dummy engine"...mind you it will make good "trimming ballast" as well as the batteries needed to haul this relatively heavy engine around the sky. Edited July 5, 2021 by Rich Griff Quote Link to comment Share on other sites More sharing options...
Andy J Posted July 6, 2021 Author Share Posted July 6, 2021 Removed the hub just to see if there was a split collet and indeed there was, so removed the collet by pushing it out. Assuming the correct assembly process is to place a washer between the engine casing and collet, then slide on the collet and then tighten down the prop hub. Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted July 6, 2021 Share Posted July 6, 2021 (edited) NO WASHER! There may be a thin thrust washer to prevent wear but this will only be 5 or 10 though thick. This is yo prevent the two alloy components rubbing and wearing. The collet should slide up to the shoulder on the crank shaft ,then place the prop driver on and fit prop and tighten . Its should lock in place on the shaft. If it doesn't then the collet may be worn or stretched . When solid on the crank the small split should ve clearly visible. If its closed then it will need re gapping to allow it to compress onto the shaft. A junior hacksaw blade ground flat to about 5 thou will do this. If comp is ĺow and there are no leaks on head or glowplug it's probably just a worn piston /cylinder. There must be loads lying around and I may even have a used set. Check first for leaks and let us know. If Piston/cylinder is worn there will be bubbles showing as blow by when you turn it over. Edited July 6, 2021 by Engine Doctor Quote Link to comment Share on other sites More sharing options...
Andy J Posted July 6, 2021 Author Share Posted July 6, 2021 The washer was perhaps 0.5mm thick and did show show markings that it had been in place for some time but will try with this removed. Given the absence of the inner and outer gaskets on the head, found air was leaking so have made a new outer gasket. Compression was improved but when turned over it still just does not feel right. Making a replacement inner gasket will be difficult given that it sits inside a 1.5mm recess. Possible I have distorted the inner piston sleeve when I gripped the top trying to remove the item. Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted July 6, 2021 Share Posted July 6, 2021 Engine doctor, might you have a spray bar and needle spare, as well as an alloy prop driver hub please, good price paid... I can send pictures and details of parts required... Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted July 6, 2021 Share Posted July 6, 2021 (edited) Andy, I have been banging on for a little while about this engine, and low and dehold when you have listened and looked, there it is. I learn something new on this place nearly every day ! Compression on my 35 was virtually non existent untill I made a head gasket, really good compression now. Even with some compression the engine will run, use straight castor and run a few tanks of fuel thru it to coke/gum/burn a good seal. Remember your engine has been cleaned using a strong detergent not to mention solvent which has no doubt removed gum etc. which was helping create a "seal"... Edited July 6, 2021 by Rich Griff Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted July 6, 2021 Share Posted July 6, 2021 10 minutes ago, Andy Joyce said: The washer was perhaps 0.5mm thick and did show show markings that it had been in place for some time but will try with this removed. Given the absence of the inner and outer gaskets on the head, found air was leaking so have made a new outer gasket. Compression was improved but when turned over it still just does not feel right. Making a replacement inner gasket will be difficult given that it sits inside a 1.5mm recess. Possible I have distorted the inner piston sleeve when I gripped the top trying to remove the item. My previous post should read "There should be a thrust washer between the prop driver and case" not an ordinary washer. Sorry got the builders in and was distracted. Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 6, 2021 Share Posted July 6, 2021 If in doubt about the head seal run a drop or two of washing up liquid around the joint & turn the engine over a few times. Any leaks will show up as bubbles. Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted July 6, 2021 Share Posted July 6, 2021 Stuck stiff little end you said, you gripped the cylinder spigot, I have seen the pictures, spray bar different to mine and a few etc.'s..... Good luck with your electrification, I hope it works. RIP dear merco 35... I am still on the hunt for a spray bar and needle, anyone got one, even a complete carb ? If none come forward I will repair my pre bent one but will need the required taps and dies or suitable brass machine screws, and appropriate drills... I will post a thread about it when the time comes, and about the dB Gyrace unless someone wants to buy it ? Quote Link to comment Share on other sites More sharing options...
Andy J Posted July 6, 2021 Author Share Posted July 6, 2021 Richard do a search on ebay sure I saw one this morning under the Merco listings. Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted July 6, 2021 Share Posted July 6, 2021 Ok will check, I know a stunt spray bar was shown, mine is RC. Just engines do a stunt spray bar, but not yet measured mine yet. Mecoa of USA may have some parts but they are difficult to contact, they tend not to reply to emails etc., and they are difficult to deal with as Thier world seems to stop at the coast and border... Quote Link to comment Share on other sites More sharing options...
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