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Engine Doctor

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Engine Doctor last won the day on March 21 2022

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  1. As you say but now use Ali tube as the brass tubing is attacked by any nitromethane in the fuel as copper is dissolved leaving pin holes. Signs are green residue around brass especially where it goes into the bung. One other thing , I fit a sintered metal clunk instead of the supplied clunks as they are brilliant filters . Strangely the copper in the Bronze sintered clunks doesnt seem to suffer or dissolve like the copper in the brass tubing although the short brass connecting tube eventually degrades .Any Chemist or metallurgist in our ranks who can explain ? I think the bond between copper and Tin in Bronze is more robbust than that between copper and zinc in Brass ?
  2. Canopy glue from DeLuxe materials would do it . Its a miky white but cures to clear but takes while grab. Not many other glues really stick to bottle plastic and if they do stick they generally embrittle the material. Canopy glue stays flexible and any unwanted glue can becleaned off with a damp cloth.
  3. Sorry got the product mixed up. Solarfilm and Solarspan were both polypropelene but the Span was a 50% thicker version. The polyester was named Supershrink polyester or Matt Ployester. The Polyester was proof agains most fuels but the Solarfilm and Solarspan would go soft and wrinkle with diesel or petrol but ok with glow. Solarfilm are still listing yheir coverings on their website. They do make the best ever fuel proofer IMO ... Clearcoat. It heat sensetive and is a great adhesive for Litespan another excellent fuel proof,tough alternative to tissue.
  4. Yes Solarfilm just kept churning out the rubbish polypropelene r8ght up until thry closed. Ok in its time but superceded by the polyester covering.
  5. Yes do . Anything to do with building is interesting to many of us . Ive sold my last boat now but who knows , IC power is my interest in any model . I have a couple of old Laser 75's and was going to convert one to marine some time back . Not difficult but the cost of the Piece of brass for a flywheel put me off 😶.
  6. Worth a try Manish and nothing to loose. Loctite can always be undone with heat a bit like cyano although be careful as you wouldnt want to distort the cases. If you stripped it now before its fully run in the parts are still relatively new so running in and fits wouldn't be a problem. The only parts you would need are a few gaskets. Give the glue a try but oil in the join might prevent it from sealing properly. Good luck.
  7. Providing it has some compression. There are some good ones out there.... its finding them thats the problem. A better bet would be to find a good used OS 26 or 30. Nice engines .
  8. You say your ASP has very little compression and that says a lot. A lot of the ASP,SC ,etc had little or no Qualty control and their FS range were badly affected. If you check valve clearance and seating and its ok the problem is usually the cyl head . These leak past the bronze valve seat inserts and the casting. This can be heard when turning over No cure as these seatings are cast in . Just fit a new head but none acailable now and even if y9u could find one chances are its also faulty. Probably your only chance of getting it to run is to buy a broken used engine ( broken lug etc)but check it has sone comoression first wnd that exhaust thread is ok.
  9. I think some of the offerings from Ripmax etc are rubbish , JMO or course others may think differently. Many of the colours are not opaque and show balsa grain through. Solarfilm polyester covering was good but the normal Solarfilm was also horrible as went saggy in sun on a hot day. The Chinese polyester covering sold online or if your lucky by your model shop is really good. I think its the same as sold by HK. Its easy to apply , overlaps really stick down well,shrinks well in all directions and stretches well around compound curves. As you say Oracover is just to expensive.
  10. Set mix to run properly (not rich) and see if it idles ok. If it wont then the leak needs fixing. Crankcase compression on a two stroke is more important than cylinder compression as it this that transfers fuel mix to cylinder and operates the pump in thr carb. Any leak if left can worsen and could eventually damage the case surfaces. Is that joint a machined mating surface or should it have a thin gasket? It does look like a mated surface . Personally I would strip it and first check for any debris in the locating pin socket thats preventing it seating properly . If any damage or marks on faces reasemble using a thin smear of gasket cement or even a smear of one hour/slow epoxy on the faces. Easily removed if needed but will make a perfect seal. Be careful not to use too much gasket cement or epoxy as you dont want any squeezing into the crankcase. You could of course try cleaning area thoroughly with alcohol then applying some 24 hr Araldite as a temporary fix Of course if you paid to have it rebuilt then return it and let them sort it.
  11. old engines often had numbers electrically etched onto the case by , i think , the distributor. DC as far as Im aware never put serial numbers on their engines . The only differences during production was that early engines had more finer cut fins on the cylinder head. Later versions had far fewer thicker fins along with poorer castings and material quality , especially the con rods. early ones and up to early sixties were great little engines and JMO better than the Mills 75 . in the last years the quality really declined and fortunately the later ones can be spotted easily,
  12. Yes as Jon says and dump any castor. It varnishes internals especially in fourstrokes where higher temperatures are produced. I recently sorted a ASP 120 FS for a mate, a Chinese copy of your OS with the recyling oil pipe from case into intake. It was very smokey , enough to set off the smoke alarm in garage. Most other engines dont produce enough smoke to set it off as I always run a large exteactor fan at the same time just behind the test stand.
  13. Yes i recently had a comp screw loosen on my Frog 150 powered Frog 45 . But engine just slowed down as comp backed off and i had to land quickly. Screw still there. I guess Gary's engines CP held in place and screw just vibrated out .
  14. Shouldnt be an issue with 2.4 radio. If it does just slip a piece of heat shrink over it to isolate it from the engine.
  15. Comp screws are not generally a problem to make/replace but the MVVS is a very od thread/ pitch combination. Its a 6mm dia with an odd pitch . 6x0.8mm is an unusual pitch but MVVS chose what looks like 0.75mm pitch ? My pitch gauge doesnt have the exact pitch . So a different approach was needed .The head was bored and threaded to 5/16 UNF and a short bolt was machined from a 5/16 UNF bolt. This was then drilled and tapped to take a M4x0.7 for replacement comp screw and screwed into the head using some strong thread lock. All sorted and ready to rock and roll with a lock bar. The pin used on DC , Mills and probably others was a good idea until the engine was run in and you needed to turn the comp screw past that position. Unscrewing the pin useually resulted in it becoming lost but or vibrating out 4BA screws were very easy to obtain and make a replacement. Just think using a a chain before 2.4 radio. That would cause radio havoc on 27 or 35 meg 😮.
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