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Engine projects


jeff2wings
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  • 3 months later...
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It is indeed a G60 RV of 1966 vintage ! yes it was looking a bit sad when I got it,it looks like some one may have converted it to marine use at some stage by taking off most of the fins,I think it may also have a later piston fitted as it should have two rings not one ? anyway it only cost me a fiver, worth it for the carb alone !

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  • 2 weeks later...
  • 3 weeks later...

very interesting thread this,l too have just taken possession of a project engine from ebay….cameras on the blink, but will post some pics asap---this engine is a petrol twin based around a pair of cylinders from crrc 50 size engines,the crankcase has been machined from billet alloy,and the standard of machining looks really good,the inlet ports have been blanked of with custom made plates,and a walbro carb sits on a machined in mount.....l am assuming that the internals I e crankshaft are custom madembut l suspect that the conrods and pistons will be from the original engines......the only markings on the engine are on the rear of the crankcase,where the letters"ftl" appear,it is a big chunk of engine,anyone know anything about it??,its a professional job,done by someone with a fair bit of knowledge,hopefully l can get it to run,but something is nagging at me about it,cant put my finger on it though,l am not really an engine man,but have dabbled in model engineering,any info will be most welcome.

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robin,that does sound very similar,my concern is the fuel mix transfer to the combustion chamber from the crankcase,the crrc 50 singles have the carb mounted direct to the cylinder,so l cant quite see how the fuel mix can transfer from the c/case to the transfer port and thence to the combustion chamber....l plan on doing a partial strip down for inspection,so hopefully all will be revealed,if it runs as good as it looks then l will be a very happy bunnysmiley

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Jack, on the single cylinder engine, the bottom of the piston acts as the valve controlling flow from the carburettor into the crankcase. On the twin, I suspect a reed valve between the carburettor and crankcase does the job, in the same way as on a Cox Babe Bee 049.

When the pistons are moving apart (going up the cylinders), there will be a negative pressure in the crankcase, which opens the reed valves allowing the air fuel mix in. When the pistons move towards each other (descending in the cylinders) the reed valve shuts, squeezing the fuel/air mixture up the transfer ports on each cylinder and into the combustion chambers.

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robin,thanks for that,what l am not sure of is whether the transfer ports are actually open to the crankcase as the cylinders are from a single cylinder engine,but,as l say,l cant see someone putting so much work in to the project with out having addressed that question,my camera should be fixed soon so l will post some pics,plus l plan to take the cylinders off for a look see at the internals

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  • 3 weeks later...

regarding my posts on the twin l recently bought,l am not really sure what size prop to use on it,as l said,it appears to be around 100cc,using a pair of crrc piston/cylinders,each of around 50cc,giving a total of 100cc,so it will swing a fairly big prop,l intend using an rxcel ignition set,so can anyone give me an idea as to prop size?,not really a petrol head so this is likely a daft question!!!.....jack,

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