: I have been following the con rod debate and wish to add my two cents.
: Previous posts have said that tractor engines do not have anything in
: common with automotive engines. This is not true,they are both Otto four
: cycle engines, improving performance of either uses the same principles.
: They both respond to change in volume and/or velocity of airflow to
: the cylinder. Rod to stroke ratio has an influence on output because of
: relationship to optimum camshaft timing.Just like an engine's ignition : advance curve can be improved, so can it's "valve timing" be improved
: to better suited to the engines application.Two 500 inch U motors : identical except for rod length would need to be "degreed" differently
: to make the most power.
: Changing an engine's stroke and it's rod ratio means you should also
: check the camshaft's position (curve) for maximum power in the intended
: rpm range, even if power is increased from the previous maximum. Carb : limited stock cars and super stock drag racers have been doing this : years to go faster, we should follow their example.
: Smokey Yunick has been mentioned on some posts advocating the use of : the longest rod possible. While this not a bad idea, remember he gave
: that advice on racing where engine size is restricted, not rpm like
: antique tractor pulling! 500 c.i. NHRA pro stocks undoubtedly have : better rod ratios than 800 c.i. IHRA pro stocks, but the big engine
: cars are faster.
: Here is the formula for determining horsepower. Torque times rpm : divided by 5252 equals horsepower. Hope this helps compare engines
: of different specs. I agree. The best performance comes from the engine that has the best matched TOTAL package. Anything that can be done on a drag,truck,boat,etc. engine,can be done to a tractor engine. The biggest limitation is RPM's. That is where the problem lies. Antique tractor pulling is the only sport where the maximum rpm is slower than any other "race" engine's idle speed. I see this as a challenge. I have a model "R" that I would like to pull.( and maybe kick some of those little orange tractors around!!!) So this is a new science to me,so I have some learning to do,myself! I think this is a great forum for discussions like this,because I can see everyone else has the situation that I do,to try and get as much out of their set-up as they can!! It's great to see such a wealth of information being shared by everyone.
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