Andy J Posted June 18, 2022 Share Posted June 18, 2022 Have a loose tank tank pressure nipple on the above silencer. Can anyone suggest a recovery method to fix the issue. Suspect it is the alloy casting that has worn rather than the brass fitting. Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 18, 2022 Share Posted June 18, 2022 OS pressure nipples are M3 if memory serves. Drill the hole out to 3.2mm and stick an M4 tap through it before fitting an M4 nipple. Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 18, 2022 Author Share Posted June 18, 2022 Thanks Jon, thread looks a lot finer than M3 on the nipple so will do a quick check with a spare nut and bolt just to be sure what I have before drilling out the silencer. See M4 nipples are readily available on ebay so should be an easy fix. Quote Link to comment Share on other sites More sharing options...
kevin b Posted June 18, 2022 Share Posted June 18, 2022 JB Weld. ? Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 18, 2022 Author Share Posted June 18, 2022 Just had another look at the nipple and it does look as though it was a BA thread as it a lot finer than metric. Unfortunately went to use my micrometer only to find it dead so assume the battery has expired. Suspect a replacement nipple will be cheaper than JB Weld Kevin its now just a matter of double checking the dimensions of what I have before doing any mod. Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted June 18, 2022 Share Posted June 18, 2022 Pretty sure OS won't have used a BA thread! Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 18, 2022 Share Posted June 18, 2022 Chuck one of these in it's place,,, and saw of the excess inside. 1 Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 18, 2022 Author Share Posted June 18, 2022 Are they called bulkhead connectors Paul? Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 19, 2022 Share Posted June 19, 2022 (edited) I don't know, maybe fuel tank nipples or something like that, Living in France for 45 years doesn't help my English,,? yes google search, fuel tank nipple,,,, PS if you need to know how to fit it (awkward ) just ask,,, Edited June 19, 2022 by Paul De Tourtoulon google search Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted June 19, 2022 Share Posted June 19, 2022 hello Andy,wrap the thread with some "thread" a couple of times and then give it a coat of either epoxy/or silicone.....worth a try... ken anderson...ne..1...thread dept. Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 19, 2022 Author Share Posted June 19, 2022 Found an old threaded nipple in my box of BA screws which seems to fit fine so have continued to play with the engine which leads me to a second problem. Whilst running the engine which took some time to find a decent needle setting noticed a few bubbles of fuel forming around the cylinder head joint so I stopped the engine and removed the 6 screws. Inspection of the head underside shows it to be a little tarnished in places but did notice no gasket is used. So the query is should there be one or do I just need to run some emery paper over the head to remove any minor high spots. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 19, 2022 Share Posted June 19, 2022 Emery paper ?, grinding paste '(tooth paste ) between the head and cylinder would be better. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 19, 2022 Share Posted June 19, 2022 Sure there's no gasket? Sometimes they are tucked away. Emery paper would ruin the top of the liner, I'd have thought. Not controlled enough. Lapping with cutting compound sounds like a reasonable dodge. What engine is it? Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 19, 2022 Author Share Posted June 19, 2022 Would not be happy using a grinding paste unless I did a full strip down as there would be a good chance some paste would get into the rest of the engine. Have two more OS 20''s coming next week so will see how they run before any further remedial work on my current engine. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted June 20, 2022 Share Posted June 20, 2022 As per Nigel's suggestion - the gaskets are usually aluminium shims and can bind to the head and be almost invisible unless disturbed. Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 21, 2022 Author Share Posted June 21, 2022 Made a brown paper gasket but have yet to run the engine. Do have some litho plate so that could be an option if the paper gasket fails. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 22, 2022 Share Posted June 22, 2022 Paper head gasket, are you serious ?, I only use Litho plate I have .3mm and .6mm Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 22, 2022 Share Posted June 22, 2022 There's a place that does laser cut gaskets. http://icbimproducts.com/gaskets/newcart/index.php No connection, simply happy customer, etc. Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 23, 2022 Author Share Posted June 23, 2022 Thanks for the link Nigel but don't like buying goods from the US given I have been hit by high postage and import costs in the past. Do have some litho plate so will give that a try on my low power laser cutter to see if it will at least mark it out to allow cutting out using hand tools. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 23, 2022 Share Posted June 23, 2022 I can lend you a compass and exacto model knife if you need it,,,? Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted June 23, 2022 Share Posted June 23, 2022 Yes should have a thin ali head shim/ gasket on the OS 20 . If the recess in the head is very shiny then it has a gasket wedged in there. Removing the gasket and annealing will often cure a slight leak unless the head has been tightened down unevenly or by a gorilla and distorted. If that's the case then it got to be replaced or if you have a scrap liner ground to a good fit. Over the years I have seen engines with all sorts of "mods" and gaskets fitted . One was a Frog 500 with a head gasket cut from a bicycle inner tube ! And the Frog doesn't need a gasket . Please don't waste time with paper gasket on head. Cut one from litho and annealed before fitting. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 23, 2022 Share Posted June 23, 2022 (edited) I'm somewhat sure you'll only pay VAT on something like a single gasket? Their international postage was quite reasonable when I ordered. Edited June 23, 2022 by Nigel R Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 25, 2022 Author Share Posted June 25, 2022 Tried using my laser cutter on litho plate but as I expected it did not even leave a mark so may well take you up on your offer Paul. Afraid I am no longer visiting France for work so you will have to drop the items in on your next visit. Did work in an Architects Office for about 4 years but blowed if I can now find all my old drawing board related items. Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 25, 2022 Share Posted June 25, 2022 2 minutes ago, Andy Joyce said: Tried using my laser cutter on litho plate but as I expected it did not even leave a mark so may well take you up on your offer Paul. Afraid I am no longer visiting France for work so you will have to drop the items in on your next visit. Did work in an Architects Office for about 4 years but blowed if I can now find all my old drawing board related items. I am not sure that I will be allowed in, French and English Nationality but my British passport has long gone so with all the paper work and Brexit I am not sure that Boris would grant me a visa, and with a Diesel the French "Greens" don't help? I don't know if I will be allow to drive through the larger French towns, so sorry I won't be visiting in the future, Quote Link to comment Share on other sites More sharing options...
Andy J Posted June 25, 2022 Author Share Posted June 25, 2022 You could give your compass to one of those chaps travelling through France on their way to the coast. However on second thoughts sharp pointed instruments and rubber dinghies don't match. Lifeboat may have to deal with a real emergency rather than a call we have got halfway come and pick us up. Quote Link to comment Share on other sites More sharing options...
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