HP and quality of todays vs. older equipment?!

[s1120]

<font color="red">The new engines certainly are more efficient from an emissions standard, and probably are more economical. I can't believe an old flat head can make the same HP and torque as an OHV engine with electronic ignition, and it would burn more fuel doing it.
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OK, I will give the nod to the new motors on HP, but torque?? No way. The key to good low end torque is a long stroke, and small valves, and ports.[and of corse cam timing to take advantage of them, but thats anouther story] In most cases to gain HP you have to spin the motor faster, or change the bore stroke ratio, or valve sizes, and port sizes.[and of corse the cam spec also] The pointed end of that stick, is that when you change for HP, you kill the torque. The real key? Look to displacment, and where the motor makes max HP.

I bet you will find the the older motors, while having lower HP, had a bigger cid, and max power at a lower RPM. And in a tractor, THATS what gets the work done.

 

[Joe1]

If I remember right, an old B & S single I had made max HP at 3600 rpm, which is about the same for the new OHV engines. It was a prett;y low HP engine, two hp I believe.

Some of the larger long stroke singles also probably had larger, heavier flywheels than some twins do today to help smooth them out with a small penalty in engine throtlle responsiveness.

An interesting thing to ponder, of course without engine specs and without being able to test them side by side it's academic; interesting, but academic.

Joe1

 

[slowzuki]

Not quite but close, the key to Torque is compression ratio (rather the b.m.e.p. to be exact) and displacment.

A modern motor of the same displacement should be able to whoop an old one it given the low end carburation isn't too poor.


</font><font color="blue" class="small">(

OK, I will give the nod to the new motors on HP, but torque?? No way. The key to good low end torque is a long stroke, and )</font>

 

[jrlichina]

The length of stoke is what determines torque(main factor). The longer stroke provides a longer "level" to turn the crankshaft. The longer the lever the more twisting force can be applied to the crank, and torque is the measurement of the twisting force of the crankshaft.

 

[art]

I believe the older engines, for the metal they are built with, and a new fuel system like what we are using on our diesels set with the torque curves they are, would grenade within an hour of locking it down!!!

 

[Chadtoolio]

Steve,

</font><font color="blue" class="small">( I'll be able to reply to this post using experience soon when my new 18hp deere has some hours on it but I have been cutting the grass for 3 years with my 1965 10hp cub cadet and attest to the over built theory. )</font>

I will be curious to see what you think...but-does your new Deere take ground engaging implements like the older ones? I have no doubt that the newer machines are engineered to cut grass finely and explicitly. No more/no less. But I think the bean counters would rather you buy a bigger machine than make a smaller one more versatile and rugged.

Chad

Good to see this post still going!

 

[bontai_Joe]

Hi Chad,
I finally made it over here. Glad to see some familiar names. /forums/images/graemlins/smile.gif Enjoyed this topic.