A really dumb question

[Guest prs519]

Old cars were propelled more with torque than horsepower, very broadly speaking. If one lugs an engine down, would it be true that the

load would be transferred all the way back to the rings on the piston, and the ring lands? This question is probably a monument to my own

stupidity, but it seems a little bit reasonable. Perry

[TexasJohn55]

Yes, different sorts of wear patterns appear on bearings as well when "lugged down" to peak torque and below.

[padgett]

If you want really low rpm you need a steam engine - maximum torque at zero rpm. REL had 15 hp at 44 rpm.

Problem with "lugging" in an IC engine is the irregular combustion causes erratic loading rather than a smooth flow of power. (If you want a deep explination, this is more an issue with carbs than FI since carbs rely on a certain air flow to draw the fuel from the chamber (venturi effect) and for proper atomization. This led to the rise of things like quadrajets with small primaries and large secondaries having an air valve to limit opening.

I had a QJ on my autocrossing Corvair Corsa that provided a very broad power band. Usually won the class. Trick was the proper setting of the secondary opening spring. Getting it rong with 750-800 cfm was an instant bog. Also had dual Aluminum Four Barrels on a 78 Sunbird but a whole 'nother story. Personally prefer FI for street cars (been using since 1970).

[TexasJohn55]

Padgett, Maximum torque at zero rpm, that's interesting and I understand the concept but would the flywheel and mass in motion add to the torque while running due to inertia?

[Dave Mellor NJ]

By lugging an engine,do you mean turning the crank in reverse? Sort of like motorizing a generator? If you overload an engine wouldn't you just stall it? When I think of lugging it's like starting out in high gear or going up a steep hill without downshifting and causing a labor knock.

[Guest prs519]

By lugging an engine,do you mean turning the crank in reverse? Sort of like motorizing a generator? If you overload an engine wouldn't you just stall it? When I think of lugging it's like starting out in high gear or going up a steep hill without downshifting and causing a labor knock.

What I meant, initially, was the loading or the engine down below its power curve to near the point of stalling, or leastwise, needing a gear change. About the same thing that Dave says, except I was thinking that all the slack in the drivetrain would be out at that point and that any counter force from the tire meeting the pavement would be transmitted back to the ring-lands and rings. I do not know how much energy would be absorbed by the oil films. I thank my mentors for their input; I never thought about how the fuel mixture interaction, causing erratic running, would enter into it. Aren't IC engines wonderful contraptions? Who would ever think such an odd collection of parts would replace the horse!? Thanks for the learnin, fellows! Ivan?

[Rusty_OToole]

The rings do not carry the torque load. Pressure would be on the top of the piston, the wrist pin, rod bearing and crankshaft. Sometimes on old engines you can tell if the engine was lugged a lot (wear on the top rod bearing shell) or revved high (wear on the bottom bearing shell).

O ya be careful if you "lug" an engine by yourself you could throw your back out ha ha lol funny joke.