Torque measurement

[Greg Hermann]

>Since the motor mounts are connected to the block , you need to rotate the
>block to compress the load cell not the crank.
>The hardest part with this method is figuring out the scale in foot pounds.
>Usually load cells are calibrated with certified weights hung from a known
>length, usually a 1 foot long bar, hence 'foot- pound'  I don't know how you
>could calculate the moment of movement that the block would place on the
>load cell. I would guess if you bolted a 1 foot bar on the engine at the
>center line of the crank and placed a 1 pound weight on the end of the bar,
>you would be able to calibrate the load cell out put for 1 foot Lb. Of
>course you would
>want to cal it to 300 ft.Lbs or what you think the engine would put out. If
>you use a 2 foot bar then 1 pound on the end would apply a force of  2 foot
>Lbs. This would save some cal weight. Your idea is  excellent  and should
>give some good results. Another way to read the torque would be to connect a
>load cell to the block about where the front freeze plug is, and the other
>end to the frame. This will make a solid motor mount that might damage the
>Trans case if you torque it to hard. You might want to try this using the
>same cal procedure, and if it works go to the mount system.
>
>Don
>
>
>> -----Original Message-----
>> From:	Ord Millar [SMTP:ord at aei.ca]
>> Sent:	Thursday, April 08, 1999 8:49 AM
>> To:	diy_efi at efi332.eng.ohio-state.edu
>> Subject:	Torque measurement
>>
>> I have some strain guages that I was thinking of attaching to my motor
>> mounts, the idea being to measure the torque output of the engine.  I want
>> to calibrate it by imobilizing the crank relative to the block, and then
>> using a torque wrench to apply a know torque in the oposite direction at
>> the
>> crank pulley bolt.
>>
>> Is there a reason why this won't work?  It seems too easy...

Well--you would be measuring the torque output of the TRANSMISSION, not the
engine--so you would need to calibrate the thing a fair amount higher for
the low gears. Look at the engine-tranny package as a black box to
visualize why this is so. And calibrating with a bar stuck through the
output yoke, with the tranny in gear, might be a lot easier approach.

Greg
>>
>>