The Stovebolt Site Forums The Shop Area Engine Shop Engine Lugging - what exactly is going on when that happens?

I know what engine lugging is and that it's bad for the engine.

What I want to know is; What exactly is going on when an engine "lugs"? And Why is it bad? What does lugging do to an engine?

Lugging generates more heat out the cooling system and exhaust and less out the flywheel. More fuel is burned for no additional benefit (speed.) It puts more stress on components (rods, pistons, crankshaft, bearings) without any additional benefit.

The definition of lugging is when adding more throttle results in no additional speed.

Lugging isn't necessarily a bad thing, unless it produces preignition- - - -which produces detonation- - - -which destroys pistons, valves, etc. If the engine happens to be running at or near its torque peak while it's being lugged, that produces the best acceleration. A pretty good way to create a "field expedient dyno" is to find a long hill where the vehicle can make stopwatch timed runs at full throttle at various engine speeds and timing settings, without over-revving. Somewhere along the way, a minimum time will be achieved, indicating the best HP/torque compromise has been found.
Jerry

If it's accelerating at full throttle, that's not lugging. Lugging is when it won't accelerate with the pedal to the metal.

I’ve been wanting to do the “hill dyno” for some time now. I have my hill picked out and everything, just have to find the right day.

In addition to the timing adjustments and timed runs, I’d like to do some fuel tinkering as well. CarbKing talks about making float level tweaks to simulate jetting/metering changes. That wouldn’t be terribly hard to do in a similar test.

For a 235 engine, is there an absolute numerical timing figure one should not exceed? Obviously, spark knock is too far.

Well, I put about 200 miles on Ol' Roy yesterday and today on the freeways at about 60mph. That's just fine with me. Knowing the actual hp I'm getting out of it isn't going to make a difference in how I use it.

I'm extremely happy with the way this truck performs. Today, some guys in a new Chevy pulling a Wells Cargo type trailer pulled up next to me on I-20 and gave me the thumbs up.

I took both hands off the wheel for laughs . The truck drives like its on rails with no veering or wandering. I never even had it aligned or anything since I installed the new tires, wheels and shocks. There's no abnormal wear on the front tire edges, either. I'm amazed.

Anyway, I love driving this truck and people love seeing me drive it. It gets as many favorable responses from chicks as the Coupe de Ville. Whoda thunk it?

Chicks probably think the guy driving the old truck is less of a danger than the guy driving the Coupe de Ville.

Are they chicks or just old hens?

What's another term for "mountain lion"????? Inquiring minds want to know!
LOL!
Jerry

No, they're 20s and 30s. Thursday there was one elderly lady who was probably in her 70s or so who commented on how much she liked it when I was getting out.

I'm just surprised that people like it so much because the truck is pretty beat up looking compared to my other vehicles.

Now that this thread has turned to chicks and old hens, I think
it’s run it’s course.