|
BajaBob-delete -> RE: 4 cycle (4/14/2004 10:06 AM)
|
The Zenoah 26cc 4 stroke is made with the same level of quality or lack there of as they achieve on their 2 stroke engines,crank case mating surfaces are not machined,there are dings and dents on mating surfaces.There is no assurance the case halves will mate squarely with out the machining.
The quality level deficiencies of their 4 stroke are compounded by its design.The reciprocating assemebly with the stamped connecting rod design and the plastic button wrist pin retainers may work well in a low rpm trimmer but are marginal in a high performance application.
The small bore diameter limits the valve sizes,the head and intake tract are tortuous at best. Up draft carburation? The large and deep swimming pool combustion chamber with the valves shrouded is reminiscent of early to mid 70s smog engines coming from Detroit.Even if larger valves could be fitted the ports do not have enough material around them to allow them to be enlarged and their shape is ludicris.This is your fathers Oldsmobile.
The oil dipper lubrication system is pure stone age,however it is in keeping with the era of technology used in the design of other systems on this engine.
The plus side of this thing,is with the removable head the compression ratio may be raised relatively easy by machining the deck face,the pushrods would need their length adjusted.A larger carburetor of the same type is recommended.freeing up the exhaust will help with an improvement made to the intake side but is most likely not necessary because the rpm capability won't increase all that much. Ignition timing could be advanced somewhat to gain some throttle response and maybe some power.
For all practical purposes this engine is best suited for a scale type of craft that doesn't require high rpm or a lot of power.
|
|
|
|
