Motor Musings

Greetings folks, and welcome to the fourth edition of Autos A-Z, your one-letter-at-a-time trip through the automotive alphabet.

In the past couple of weeks, we’ve covered ‘A’ - axles, ‘B’ - bearings, and ‘C’ - carbs; now it’s time for ‘D’ - diesel.

That’s diesel, as in Rudolph Diesel, not Vin Diesel.

At this point you might just be asking yourself, “who’s Rudolph Diesel? I thought this was an automotive website.” You’re right, and it is.

Rudolph Diesel is the man that the diesel engine is named for, although he didn’t power his first engine with (what is now known as) diesel fuel. Instead, he used powdered coal.

Vin Diesel is (supposedly) an actor, starring in such movies as xXx and the Chronicals of Riddick.

The big difference between diesel engines and traditional otto-cycle gasoline engines is that in a diesel engine the fuel is not injected until after the compression phase. This allows a much greater amount of compression, and therefore a greater efficiency. If you tried to compress a gasoline-air mixture that much, the fuel would pre-ignite due to compression heating. This can be explained by the ideal gas law.

This high compression ratio is also what gives diesel engines so much low-rpm torque compared to gasoline engines, therefore making them more suitable to heavy trucks and buses.

In summary

• Autos A-Z
• D is for diesel
• Rudolph Diesel invented an engine
• Vin Diesel is (supposedly) an actor
• Diesels are efficient

Any questions? Fire away in the comments.

Greetings fellow motorheads, and welcome to the third installment of Autos A-Z. This time we’re going back in time for carburetors (or carburettors if you’re British). I’ll abbreviate (why is that word so long?) as carbs from here on.

Almost anyone who’s ever owned an old car (or almost any motorcycle) has had an opportunity to tear into the carb(s) at some point. Most of us fall into one of three categories.

1. AAIIIHHH!! What are all these little pieces? Let’s face it - carbs are complicated. Some people just don’t get them. This group will eventually purchase a new carb and install it, or sell the car as a project. There’s no shame in admitting your weakness.

2. Holy Cow! It runs! This is by far the largest group (yep, that’s me over in the corner there), consisting of those who manage to disassemble the carbs and clean/replace parts as necessary. Upon reassembly the car runs, but we’re not really sure why. As long as there are no parts missing from our carbs when we start, we’re probably gonna be ok.

3. The Guru. You need a carb for your Whoozawhatzit? No problem. I’ve got one from a Whatchamacalit right over here. Just let me change these hangers and find the right jets. Oh, these emulsion tubes here will work. Now let me find a new needle and seat . . .

If you find someone in the last group, consider yourself lucky. Almost anyone can learn to rebuild a carb, but few will ever truly understand the intricacies of their workings.

In summary:

• Autos A-Z
• ‘C’ is for carburetors
• carbs are complicated
• Guru’s are good

Any comments? Suggestions for future episodes of Autos A-Z? Let us know in the comments.

carbs, Autos A-Z

Greetings fellow autohounds, and welcome to the second edition of Autos A-Z. This time I quite arbitrarily chose bearings as the subject of my meandering alphabetical ramblings.

That ‘arbitrarily’ part above is something of a lie. In addition to needing an auto part starting with the letter ‘B’ (this is the second edition of Autos A-Z, get it?), I just finished replacing a rear wheel bearing in my Wife’s 1998 Audi A4. This was not fun. Not fun at all.

Brakes are much more fun. Maybe I should have written about them instead. Oh well, I guess I’ll need something starting with ‘B’ for the next time around.

Where were we? Oh yes, bearings! You see, back in the old days, bearings were user-serviceable parts. They either had a zerk fitting built into the housing, or they could be disassembled and repacked with grease. They even sell great tools to help with this messy task. On most (all) cars today, this tool won’t help you at all, as the bearings are “sealed for life”.

They must mean the life of the bearing, not the life of the car; very rarely will all four wheel bearings last 150,000 miles. They will, however, last the life of the new-car warranty, that being the point.

At any rate, the Audi is much more pleasant to drive now, without that incessant howling from the left rear wheel.

To summarize:

Anything to add? Please let us know in the comments. We’re eager to hear from you.

Greetings fellow auto enthusiasts and welcome to the first of a series of automotive articles in which we here at Motor Musings (by “we” I mean “I”) will attempt to - at random intervals - explain one part of a car, truck, boat, or plane for each letter of the alphabet.

For no particular reason I chose to start with the letter ‘A’. After long consideration (at least five seconds) I decided to enlighten the masses (that’s you) about axles.

In it’s simplest form, an axle is just a shaft on which to mount a couple of wheels. Think about the little red wagon you had as a kid. The metal bar that ran between the wheels was the axle. This works fine for the simplest of vehicles (heavy duty trucks still use something similar), but for a better ride we need something a bit more complex.

One of the biggest problems with solid axles is that anything that affects one wheel directly affects the other wheel on that axle. If your right front wheel drops into a pothole, your left front wheel will no longer be perpendicular to the roadway. In a curve this could be disastrous - especially if you were driving near the limits for that curve.

Enter the independent suspension. Early Volkswagen Beetles used a simple independent rear suspension (IRS), called a swing axle. It improved on the solid axle by preventing the movement of one wheel from affecting the other, however the moving wheel still exhibits camber changes. That is, as the wheel moves up and down it deviates from perpendicular to the road.

Today’s independent axles have improved upon this tremendously. Many hours of calculations go into the design of the suspension’s pivot points in order to keep the wheel firmly planted to the road under all foreseeable circumstances.

To summarize:

As usual, if you have anything to add, let us know in the comments.

Cheers,
Dorri

axles, Autos A-Z