How to determine a continuous torque or power for an automobile engine

Super. Just what I was looking for.

The word for today is "dynamometer."

Well, yes, but I don't seem to have one of those, and they are not cheap.

Smartphones have sensors for acceleration, location, speed, elevation, etc. Given tire sizes and gear ratios, an app can compute RPM. Horsepower can be computed by torque x rpm.

I haven't tried this one, but it's something to look at. There are probably others out there also.

https://play.google.com/store/apps/details?id=brandoncharliekaylie_industries.com.g_meterapp&hl=en_US&gl=US

Computing isn't the problem. The problem is determining where, on an engine's performance map, you can safely operate it for long periods.

Do some digging into current mfgr testing procedures. I think you'll find that your fears are unfounded. The torture and duration of that torture is far worse than any reasonable, or even unreasonable, person is likely to inflict on an engine.

Will do.

Stellite valves practically eliminated valve wear,and I think Plymouth was the first to use them.

I wonder what the limiting factors are now?

I would think clean oil,clean air,and proper oil temperature,around 160F,and the number of thermal cycles.Cold starts do a lot of harm in gasoline/diesel engines.

It does help.

I had assumed that bearings would be the problem - that an engine with more main crankshaft bearings would last longer at higher load. I hadn't thought about the valves.

The rule about rpm cubed will be useful.

The long life of engines running 1500 to 2000 rpm makes sense, as that is the speed at which they usually operate in automobiles, except for overtaking and hill climbing.

There are always some outliers in every field,and I know of one in particular:A 1959 VW beetle.A friend drove one over 2000 miles every weekend for many years.The odometer had tripped over several times,and it still ran great,no smoke,using only a quart of oil every 3000 miles.I asked him how often he changed the oil.He said "Never changed it.Just added a quart when it gets low."

How often do you have the valves adjusted "Never had them adjusted,he replied."

It sounded incredible to me because VW beetles do not have an oil filter,just a strainer,and the valves need adjusting every 3000 miles,and#3 exhaust valve is the weak link in the motor because it gets hotter than the others because the oil cooler blocks some of the air flow to number3 cylinder.

I decided to look up the serial number,and discovered it was an industrial engine,made for a generator that had been transplanted into the car before he got it.36 hp rated,but he could keep up with I 95 traffic from Florida to Virginia and back,but he confessed to drafting big trucks to keep up at 70 mph.

He said he could practically let off the gas and let the draft pull him along.when he got close enough.

I told him he liked to live dangerously,but he said that he could stop a lot faster than the truck,and if he saw brake lights on the truck,he hovered over his brake pedal with his left foot.

The body finally rusted out to the point that it was un drive-able,and he junked it.

I would like to have been able to tear that motor down and find out what was so special about it.

My suspicion is that the valves and valve seats were harder (see an earlier reply to my question) and the engine had more (or better) main crankshaft bearings. Better baffling would help the "hot" cylinder head (VW baffling was pretty primitive).

And then, if it was an industrial engine, running a slightly rich mixture would reduce the thermal load and reduce detonation.

My suspicion is that the valves and valve seats were harder (see an earlier reply to my question) and the engine had more (or better) main crankshaft bearings. Better baffling would help the "hot" cylinder head (VW baffling was pretty primitive).

And then, if it was an industrial engine, running a slightly rich mixture would reduce the thermal load and reduce detonation.

<...to rev the engine up to the rpm corresponding to maximum torque...>

Torque is the property presented to the prime mover by the load. With no load attached, the prime mover is not overcoming any torque, and therefore not developing any shaft power.

[Output shaft power] = [torque overcome] x [shaft speed]. It is quite possible, and indeed usual, for the peak torque capability and the peak output power to be at different shaft speeds.

Correct. I was just referring to the alarming noises made when the engine approached, at no load, the rpm at which maximum torque was developed at full throttle.

Loose bearings? They would be quieter under load.

Of course they are not. Won't brake right away, but continous stressing is not what they're designed for. And another thing, actually reving with no load is a bit worse mechanically than reving under moderate load. Now thermally it's another story. Depends on the design and engine condition. On the other hand keeping revs low is good most of the time for gas millage, but does stress parts like catalytic onverters, engine mounts and other things on less than perfect designed engines, increases carbon deposition all around from EGRs, can increase fuel dilution caused wear etc. And if I need max 60HP all the time why on earth I would buy 300? (LOL) S.M.