Engine Doctor Posted August 11, 2023 Share Posted August 11, 2023 (edited) This might be of interest to some of you. I bought a couple of old Laser 75's at a swap-meet earlier this year. Both have decent compression so thought I would give them a refurb. I originally intended to convert one to a marine unit as a marine four-stroke sounds really good . However the cost of some brass rod of the diameter needed was rich so shelved the idea for now. I wanted brass as our local lake is brackish and it kills alloy in short order . I might have a go later making a water jacket from alloy and use a heat exchanger so not to cause damage to engine . Anyway with engines all cleaned and ready to re-assemble using new bearings i found i had to make a replacement PTFE gudgeon pin pad as one mysteriously disappeared ? Piston rings seemed ok so after removing and cleaning the grooves were re-fitted . I decided to brighten them up by anodising some of the casings . The results can be seen below . All parts were done in the same bath at the same time but obviously the different alloys take up the dye at different rates . Im currently looking for a couple of laser mufflers if anyone has a couple lying around . The ones i have have been battered and dented so a couple of fresher ones would be nice . If you have anything let me know but no silly prices please. Edited August 11, 2023 by Engine Doctor 5 Quote Link to comment Share on other sites More sharing options...
Alan Hilton Posted August 11, 2023 Share Posted August 11, 2023 45 minutes ago, Engine Doctor said: This might be of interest to some of you. I bought a couple of old Laser 75's at a swap-meet earlier this year. Both have decent compression so thought I would give them a refurb. I originally intended to convert one to a marine unit as a marine four-stroke sounds really good . However the cost of some brass rod of the diameter needed was rich so shelved the idea for now. I wanted brass as our local lake is brackish and it kills alloy in short order . I might have a go later making a water jacket from alloy and use a heat exchanger so not to cause damage to engine . Anyway with engines all cleaned and ready to re-assemble using new bearings i found i had to make a replacement PTFE gudgeon pin pad as one mysteriously disappeared ? Piston rings seemed ok so after removing and cleaning the grooves were re-fitted . I decided to brighten them up by anodising some of the casings . The results can be seen below . All parts were done in the same bath at the same time but obviously the different alloys take up the dye at different rates . Im currently looking for a couple of laser mufflers if anyone has a couple lying around . The ones i have have been battered and dented so a couple of fresher ones would be nice . If you have anything let me know but no silly prices please. I might have an original small one kicking around I will have a look if you are interested postage costs only 1 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 11, 2023 Author Share Posted August 11, 2023 Thanks Alan . E.D. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted August 11, 2023 Share Posted August 11, 2023 Very nice, still not having much luck with my anodising ,are these any good for a marine conversion Ex Merco 61 Quote Link to comment Share on other sites More sharing options...
Rich Griff Posted August 11, 2023 Share Posted August 11, 2023 Very nice ed.... I have a merco 61 single glow plug from memory if you need any measuring done but since your marinising a laser perhaps not relevant. You going to use thermosyphon ( probably not good enough ), geared pump or even an electric pump through an onboard heat exchanger or outside of hull "tube"......? Interesting project none the less. I am still at the "jotting ideas down on paper" stage for a pull start mechanism with recoil, centrifugal clutch/electro clutch, gearbox to achieve some sort of reverse which may be electro selection, even ic driven Genny then electric powered..... That actual project is for the future as I will need some sort of trailer that will pass through the kissing gates on way to the lake, far too heavy to carry stuff. I did make a seagull ob motor type pull start that holds the flywheel on which works and on board glow system. Would prefer petrol powered but not found strimmer motor small enough. I know Kawasaki make an 18cc air cooled 2t motor with centrifugal clutch... As said, future project...projects..... Huntsman, the longer wood one but have a f/glass perkasa in the loft..... Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 12, 2023 Author Share Posted August 12, 2023 13 hours ago, jeff2wings said: Very nice, still not having much luck with my anodising ,are these any good for a marine conversion Ex Merco 61 Hi Jeff . Thanks , ill get back to you re the flywheels will take some measurements . What problems are you having with your anodising ? Quote Link to comment Share on other sites More sharing options...
Alan Hilton Posted August 12, 2023 Share Posted August 12, 2023 Hi ED found it I’m in Hastings are you or any of your mates coming to the Hastings club flyin next month .Bert Baker usually comes Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 12, 2023 Author Share Posted August 12, 2023 (edited) Hi Alan Unlikely Ill be down there .I know Bert but rarely see him , I live in kent and likely will be at the southern model show .otherwise could you post ? Will Pm you my address . regards. PM sent PS anyone looking I'm still looking for a second ehxaust Edited August 12, 2023 by Engine Doctor Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted August 12, 2023 Share Posted August 12, 2023 I would think once you have that as a pattern ED it's well within your skill set to scratch build one Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 12, 2023 Author Share Posted August 12, 2023 Hi Jeff . It probably is but if i can find another i can be doing something else.😉 Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted August 12, 2023 Share Posted August 12, 2023 😄😄👍 oh,anodising, think it maybe a power supply issue but I'm not going to worry about it until w*nt*r sets in ! Interesting that the blue different intensity but the red is fairly constant ? Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 12, 2023 Author Share Posted August 12, 2023 Yes think its a different batch of alloy . Consistency in colour and intensity is really difficult hard to achive. Try to achieve 1 ampere from a 12 volt supply . Also a auto stirer helps . Quote Link to comment Share on other sites More sharing options...
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