Scott Edwards 2 Posted July 2, 2023 Share Posted July 2, 2023 That's a mint 90 ! 11 cooling fins is the giveaway. Possibly manufactured 1985-1987 or so ? The Laser "ripoff" was the Flyte 150 in the mid 90's. Very crappily made and an obvious copy. It was basically made of chocolate 🤣 Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted July 8, 2023 Share Posted July 8, 2023 I couldn't resite it, old Laser instructions, if they have already been posted please delete. Laser operating instructions - 2010.pdf Link to comment Share on other sites More sharing options...
Andy J Posted July 11, 2023 Share Posted July 11, 2023 About to put my Laser 75 back into service in a Flair Bristol F2B. Yes I know the recommended engine would be an 80 but the 75 is the largest I have available. So have not had the engine apart since I purchased it about 10 years ago so thought I would at least have a peak inside. Having removed the front crankshaft assembly was pleasantry surprised to find it pretty clean inside so declined to dismantle the engine further. However I will check the tappets, so what clearance do you suggest Jon? Also I assume a 13x6 is ok for this application or can I get away with a 14inch prop? Link to comment Share on other sites More sharing options...
Jon H Posted July 11, 2023 Author Share Posted July 11, 2023 We discontinued the 75 back in 1992 so if you bought it new 10 years ago its not a 75 and probably a 70. If its a 70 then 13x6 is fine. If you arent sure what the engine is, grab a photo and we can sort it. Link to comment Share on other sites More sharing options...
Andy J Posted July 11, 2023 Share Posted July 11, 2023 No it was second hand Jon so it likely is very old. Photo was posted on June 14 in this thread and identified as a 75. So what valve clearances do I aim for? Link to comment Share on other sites More sharing options...
Jon H Posted July 11, 2023 Author Share Posted July 11, 2023 ah fair enough. .1mm or 4 thou will do for the valves Link to comment Share on other sites More sharing options...
David Davis Posted July 18, 2023 Share Posted July 18, 2023 Ok so this is not a particularlarly technical question but I am finishing off the construction of a DB Sport & Scale Auster. https://www.dbsportandscale.com/auster-j1-6515-p.asp I have three unemployed Laser engines, one of which will be fitted into this model and one of the other two will fit my Warbirds Replica Hurricane once I get around to building it. The engines in question are a Laser 70, a Laser 80 and an old but very strong Laser 75. Which would you fit to the Auster? Link to comment Share on other sites More sharing options...
Jon H Posted July 18, 2023 Author Share Posted July 18, 2023 The 75 or the 80. They are almost identical in terms of external dimensions and will offer plenty of power for the Auster. Whichever one is left over can go i the Hurricane. As i commented on another thread a few minutes ago i would ditch the hardwood rails and modify the model to take a nylon mount. Its gong to be much better in the long run Link to comment Share on other sites More sharing options...
David Davis Posted July 18, 2023 Share Posted July 18, 2023 Ok John. I would like to fit the later silencer to the 75, I've run the engine successfully on my test stand using a silencer borrowed from a Laser 70. With the original silencer it was too noisy. Is the silencer available as a spare? If so how much is it? I will be visiting England in August so i'll give you an English address to send it to. Link to comment Share on other sites More sharing options...
Jon H Posted July 18, 2023 Author Share Posted July 18, 2023 we no longer make exhausts for the 75 and our current design will not fit. If the exhaust you stole from the 70 has a single O ring then stick that on the 75 and i can supply a new one for the 70. Link to comment Share on other sites More sharing options...
Andy J Posted July 21, 2023 Share Posted July 21, 2023 Jon couple more queries also related to the Laser 75 exhaust. What threading are the grub screws securing the exhaust and what size is the O ring. Had to turn the exhaust to make it fit in the Flair Bristol and found one of the exhaust screws very tight so had to resort to brute force rather than an allen key and once I removed the exhaust I found the o ring could do with being replaced. Link to comment Share on other sites More sharing options...
Jon H Posted July 21, 2023 Author Share Posted July 21, 2023 4ba for the screws and BS011 for the O ring. I can supply O rings, got plenty of those. The grub screws are long gone though so a cap head will have to do. Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted July 21, 2023 Share Posted July 21, 2023 EKP Supplies have 4BA grub screws Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted July 21, 2023 Share Posted July 21, 2023 I bought these, Joint Torique OR-7X2-FPM70 Générique, Diamètre intérieur 7 mm, Diamètre extérieur 11 mm, Epaisseur 2 mm, matière FPM ID 7 x OD 11 2mm thick. Link to comment Share on other sites More sharing options...
Andy Stephenson Posted July 21, 2023 Share Posted July 21, 2023 Modelfixings also have BA grub screws in stainless or 14.9 with 3 different end types. https://www.modelfixings.co.uk/stainless_grub_screws.htm Also Orings https://www.modelfixings.co.uk/o_rings.htm Link to comment Share on other sites More sharing options...
Jon H Posted July 21, 2023 Author Share Posted July 21, 2023 Oh they are available, you should just bring some port and crackers to go with them. 1 Link to comment Share on other sites More sharing options...
Andy J Posted July 21, 2023 Share Posted July 21, 2023 PM sent re the O rings Jon. Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted July 31, 2023 Share Posted July 31, 2023 Hi Jon, My 300v twin has just had an intake valve spring fail. Fortunately this happened on the ground before flying. I can't see any signs of rust on the spring (see pictures ). The engine was running at about 7700-7800 rpm max on the ground (Menz 20x7) so I don't think the rpms were too high. Did I just have bad luck or am I doing something wrong? Or is it an issue with a bad batch of springs or something and should I change all the springs for the peace of mind? Anything to be doen to prevent this happening again? Anyways, how do I carry out the spring replacement? Shall I loosen the small phillips screw in middle and then screw the axle out? Anything else that I should take in consideration? another thing: I'm planning to borrow one spring from my 240V to be ably to fly without much of delays - I suppose the spring is the same on both engines? thanks, Artto Link to comment Share on other sites More sharing options...
Andy Stephenson Posted July 31, 2023 Share Posted July 31, 2023 I changed the springs on a 150 and if I remember correctly the rocker pivot has to be removed to lift the rockers clear of the valve stems. The tricky bit is to remove the collets without losing them, it's best to order a few spares along with the new springs. Also, there are spacers on the pivot bar which are awkward to get back into position when putting it all back together. Link to comment Share on other sites More sharing options...
Engine Doctor Posted July 31, 2023 Share Posted July 31, 2023 Remove and fit the collets with the head inside a large polythene bag big enough to get you hands in . If one does pop off it wont then fly into the abyss of your workshop. 1 Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted July 31, 2023 Share Posted July 31, 2023 Thanks Andy & Engine doctor good hint to use a plastic bag! Can you carry out the spring replacement without taking of the head? Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted July 31, 2023 Share Posted July 31, 2023 2 hours ago, Artto Ilmanen said: Shall I loosen the small phillips screw in middle and then screw the axle out? Probably just a slip of terminology but that looks like a Posidriv screw - if so, please use the correct driver as a Phillips driver is likely to damage the head. Perhaps Jon can confirm? Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted July 31, 2023 Share Posted July 31, 2023 (edited) 27 minutes ago, Martin Harris - Moderator said: Probably just a slip of terminology but that looks like a Posidriv screw - if so, please use the correct driver as a Phillips driver is likely to damage the head. Perhaps Jon can confirm? After having had a second look it is actually a posidriv screw. Thanks for notifying, Martin Edited July 31, 2023 by Artto Ilmanen Link to comment Share on other sites More sharing options...
Andy Stephenson Posted July 31, 2023 Share Posted July 31, 2023 When I tried the poly bag thing it just fogged up with condensation and I couldn't see a thing so I always do it very carefully out on the bench. Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted August 1, 2023 Share Posted August 1, 2023 (edited) 6 hours ago, Andy Stephenson said: When I tried the poly bag thing it just fogged up with condensation and I couldn't see a thing so I always do it very carefully out on the bench. I put mine over the engine's head, not mine,,,😄 I also put a magnet in the bag. Edited August 1, 2023 by Paul De Tourtoulon Magnet 2 5 Link to comment Share on other sites More sharing options...
Recommended Posts