Quote:
Originally Posted by rgx107
I was only trying to describe where the heat comes from and how much. And that the longer stroke / shorter rods of the 300 will produce slightly more heat compared to the 250 - even at the same power output..
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well, not quite the case... you see you are right about extra friction because of the stroke and the big bore= more heat production, but the short rods help in other points to prevent overheatingwhich might take pages to write down... but the most important factor is that they stay for LESS TIME at the TDC than a longer rod (I am talking about rod length, not stroke...) which, besides needing less advance spark timing (which also affects heat production...) keeps piston "bouncing" less on the cylinder walls, thus producing more friction....
the thing in Bruce's case is that he is using alla that "super frictious" moving parts in a totally outdated casing with only 2 liters of oil to cool all that extra friction, without oil cooler, without fins under the oil pan, like the 300 etc, a relatively inadequate (for such a huge mod) radiator, an also outdated and low-rate water pump in combination with low moving speeds at high revs...
the 300 casing takes more oil (3L), cools it better (external filter, fins etc), has an upgraded water pump and radiator with heat shield etc so it can cope better with the longer stroke.... I have been dealing with the same issues myself so I eventually decided to move on to a whole 300 transplant...