thanks for the tutorial on piston design, i am sure someone here learned something for the effort.
the thing i keep coming back to is this, i find it hard to believe that honda is ok with a cold start at 20 or more below zero, going to full throttle and full rated load within a few seconds of being first lit up.
i don't care what oil you want to use!
years ago i was tasked to find out why a quarter midget race car powered by a 500cc single cylinder honda could not finish an 8 lap race without scoring its cylinder...
the reason was the piston fit was too tight for the application, the car weighed in at about 3 times what the bike the engine came off of, the airflow was inadequate and the piston would very quickly out grow the bore.
it didn't score due to ring end gaps or the size of the piston head, it scored due to too little clearance between the barrel/body/skirt of the piston and the cylinder bore. opening up the clearance to near .008" (about 3 times the honda spec) corrected the problem.
if you recall cummins diesels scoring cylinders on cold morning startups, wherein the driver would jump in, startup and haul ass out the gate would score the cylinder,, it was not due to ring gaps or piston head as cummins piston heads are decidedly smaller than the skirt diameter, it was scoring of the skirts and overheating of the liner which would burn the liner packing and you got antifreeze in the oil.
so unless you allow the honda to warm up a bit on a cold startup before you apply a full load my bet is you will run the very real risk of scoring.. i see no way around it with 20 or more below zero F.
the coefficient of expansion of the aluminum alloy vs that of the iron sleeved cylinder will certainly be a problem.
either that or the engines are set up with loose fitted pistons to start with, in which case maintaining piston sealing is problematic, so a compromise would have to be made. a compromise that would not enhance normal temperature longevity, so it is hard to imagine why honda would make that compromise in order to allow operation in sub zero climates under this sort of startup/load demand.
now what i would accept is honda might spec an engine for such use, with the understanding that the reduction in longevity is traded for the ability of abusing the $#|+ out of the engine with such a demanding startup.
there really is no reason that anyone should design a genset for this sort of duty other than for emergency backup power use.
this is why we see gensets sold surplus for pennies on the dollar that have less than 500 hours on them... it is well understood that the engines have had the living $#|+ demanded of them and as such have lost a significant amount of their lifespans.
personally i would never recommend to anyone in your position to design a system that would place this sort of startup requirement on a generator,, its just not good engineering in anyone's book!
the idea that you have to have power "Right now" is not reasonable, and i would refuse to sell you a unit to be used in such a manner. if cummins wants to do so, fine, they have deep pockets and they are charging twice what the machine ought to sell for anyway.
you will never convince me, nor would anyone else in a similar installation that an automated system with an appropriate delay to provide for warmup before the load is applied is not acceptable.
there is no reason that you or your wife, could not wait the requisite amount of time needed to provide for such a warmup. the idea that you want to start a load of laundry "now" rather than having the washer start when the power is available a couple minutes later seems without merit to me.
now if you came to the table and said i must have this sort of performance because of my medical needs such as some sort of heart monitor, or similar thing that is mission critical, then i would say fine, lets build you a generator that will not only start reliably at 50 below zero but also take on a full rated load within a few seconds... but this is not the case!
i think sometimes we make unreasonable demands of a system and its components, and are unhappy with the cost, with the longevity or performance of the system in general or some component part when it fails to meet our "want" instead of our "need"
i guess i would not want to hear you come back here, bitching about honda in the event that on a very cold morning even though it started you scored the cylinder and damaged the engine trying to get a hot cup of coffee "right now" instead of waiting a couple minutes for it to warm up and stabilize first.
i would not see this as a fault with honda, i would attribute the failure to owner abuse!
hey, but thats just me
i have always been the poor guy that has to clean up the mess when folks abuse equipment, and it is never their fault it is always the POS equipment that is at fault, at least this is what they would have you believe.
bob g