Engine Running-on
Hi Nano
I have registered to see if I can get some assistance with the WASP CRF 0.12. running in a RRR.
I have three motors (early editions), two pipes (EFRA 2626) two CRF clutches, tapered venturis, innumerable spare parts and bearings etc. Also two of the 2007 carby update. No one here in Melbourne (16% nitro) can get any of these motors to run at a reasonable running temperature, say 120C and so give reasonable power without severe running-on at throttle lift-off or when pitting for fuel. It is so bad that since Christmas we have been trying to sell the whole lot but no one is interested, even at 1/3 original price and most is brand new or near new!
Reading through the Forum I have noted a couple of items that strike a bell such as damaged crankpins, leaking end bells and liners that are very tight in the crankcase. I have had all these problems. Our first motor, after an hour or so running for tuning attempts and one race meeting ended up with an oval crankpin measured at 0.2mm out of round - no kidding! I found the liner very tight in the rankcase and have noted oil leaking from the end bell. These were fixed with a new "o" ring, conrod and crankshaft - but how long will the new crankshaft last? The WASP crankpin is virtually half the size of an equivalent NovaRossi so I really have a problem with the loading on these pins. Is a new design being considered?
Now to the liner. Would I be correct that the tight fit is intentional to reduce, as much as possible, the air gap that forms due to differential expansion rates between the steel liner and the aluminium crankcase? It is probable that when hot (normal operating temperature) the expansion of the crankcase is much more than the liner and this develops an air gap beween the inlet and exhaust ports which results in the incessent run-on. What do you think? Would a soloution be to use a Nikasil plated brass liner?