[AT] Horsepower Question

[David Rotigel]

Thanks for the info Carl! Has this sort of "meltdown" ever been tested?
	Dave

On Oct 7, 2010, at 7:38 PM, carl gogol wrote:

> Dave-
> I only check personal email once a day so I am a bit slow in  
> answering.
> In order to control end cost, the cooling of these small lawnmower  
> engines
> are not designed for cooling more than the average anticipated  
> load.  The 20
> HP rating is for peak horsepower, which it might be able to produce  
> for a
> few minutes without the engine getting too hot.  However, if you run  
> it
> continuous at the peak HP its temperature will quite rapidly rise  
> past the
> design temperature limit.  At that point it is just getting worse  
> faster as
> the temperature goes up the oil breaks down and the friction  
> increases and
> ....
> To produce peak HP you are requiring a higher throttle setting than  
> the
> continuous load rating in order to get more fuel into the cylinder  
> -- which
> produces proportionally more waste heat.  These engines might be  
> able to
> continuously provide 10 HP (maybe less) because usually no more than  
> that is
> needed.  There is enough mass in the block to absorb additional heat  
> for a
> short period, but then the block's temperature starts to rise fast  
> due to
> its limited cooling area.  No problem for a short period, but  
> continuous
> full production at maximum short term rating will cause failure due to
> temperature induced bearing and piston failure.  They are aluminum  
> after
> all.  If you want to try this, do it on a real cool day because on a  
> hot day
> it will be over quickly.
> Carl Gogol - Manlius, NY
> Tasty grazing in the Oran valley of Central NY
> AC D14, 914H
> JD 5320 MFWD
> Kubota F-2400, B7300HST
>
> ----- Original Message -----
> From: "David Rotigel" <rotigel at me.com>
> To: "Antique tractor email discussion group" <at at lists.antique-tractor.com 
> >
> Sent: Wednesday, October 06, 2010 8:09 PM
> Subject: Re: [AT] Horsepower Question
>
>
>> Hi Carl, Why would that be the case?
>> Dave
>>
>> On Oct 6, 2010, at 7:26 PM, carl gogol wrote:
>>
>>> If your lawnmower engine had to actually produce 20 HP for an hour
>>> it would
>>> probably melt
>>> Carl
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