The new engine
Posted: 13 Jul 2020, 00:57
Started on this particular design some 4 years ago but as is sometimes the case, things get put on hold.
Photos below show the timber patterns both for the external sand castings and for the cores.
Friend of mine, George Punter, has been doing aluminium casting for many years and his expertice comes in handy against my limited (I might add successful) attempts. George is last years Duke of Edinburgh Award winner in the UK in model engineering.
Engine will be V8 water cooled somewhere around the 50cc mark, spark ignition petrol fuel, four stroke, centre top cam with pushrods and rockers to overhead valves, sump with oil pump. At this stage, hall effect sensor for either cdi or kettering ignition and possibly some temperature monitor.
Most of the design will follow the already tried and proven 25cc four cylinder I built a few years back. As with this, the V8 will eventaully get to live and work in a scale model boat, type yet to be decided on,however it would be a shame to conceal the engine down in the hull so this will be a consideration.
Patterns yet to receive a final coat of paint after a trip to see George and a couple of minor modifications.
Lower left is the sump cover which is a pattern for both the sump and the core of the same.
Top left and centre are the core boxes for the internal waterways and the crankcase inner core. 2 of each of these are used within the casting.
Finally the patterns for the crankcase itself.
Eventually will get around to the rocker covers.
George loaned me a set of aluminium patterns for the piston cores which makes for far less machining as it is then used as it comes from the casting process. Outer pattern for the piston is timber as shown in the last photo.
The four cylinder I built used 20 x 20mm pistons turned from solid whereas with George's piston molds, I can select anywhere between the same and around 22mm diameter, hence the previous "around 50cc".
Also in the last photo is the outer pattern and core for the lower crankcase.
Photos below show the timber patterns both for the external sand castings and for the cores.
Friend of mine, George Punter, has been doing aluminium casting for many years and his expertice comes in handy against my limited (I might add successful) attempts. George is last years Duke of Edinburgh Award winner in the UK in model engineering.
Engine will be V8 water cooled somewhere around the 50cc mark, spark ignition petrol fuel, four stroke, centre top cam with pushrods and rockers to overhead valves, sump with oil pump. At this stage, hall effect sensor for either cdi or kettering ignition and possibly some temperature monitor.
Most of the design will follow the already tried and proven 25cc four cylinder I built a few years back. As with this, the V8 will eventaully get to live and work in a scale model boat, type yet to be decided on,however it would be a shame to conceal the engine down in the hull so this will be a consideration.
Patterns yet to receive a final coat of paint after a trip to see George and a couple of minor modifications.
Lower left is the sump cover which is a pattern for both the sump and the core of the same.
Top left and centre are the core boxes for the internal waterways and the crankcase inner core. 2 of each of these are used within the casting.
Finally the patterns for the crankcase itself.
Eventually will get around to the rocker covers.
George loaned me a set of aluminium patterns for the piston cores which makes for far less machining as it is then used as it comes from the casting process. Outer pattern for the piston is timber as shown in the last photo.
The four cylinder I built used 20 x 20mm pistons turned from solid whereas with George's piston molds, I can select anywhere between the same and around 22mm diameter, hence the previous "around 50cc".
Also in the last photo is the outer pattern and core for the lower crankcase.