Another car questions + opinions

[MadMan]

Originally Posted by Telecolor 3007

As a Europeanen I find strange some of the past regulation reguarding hadlamps in U.S.A.

The requirement for sealed beams dates back to the early days of electric light. Cars (if you were lucky enough to have that new-fangled electricity on your car!) used to have a small light bulb inside a big lens housing, just like today. But because of light bulb technology being rather poor back then, the filament burning off would blacken the inside of the glass bulb and it would make very little light, which would be very dangerous to drive at night. Especially since halogen lights were not a 'thing' yet. So for safety's sake, the government said you need to use sealed beam lamps, because the filament is in such a large space, that when it blackens the glass, it would only be a small part, and would still emit enough light to be safe.

Of course, light bulb tech was probably good enough by the 50s or 60s to not warrant this anymore, but it's just one of those laws that stayed on the books for too long a time. By the late 80s, the regulations were changed. Some new trucks still use sealed beams, probably just because they're easier to manufacture - and the carmaker does not need to have a headlight design approved by the Department of Traffic (DOT).

[bgadow]

Sealed beams were a selling point for some makes pre-war but designers lost some freedom. Some makes in the late 30's had some very sleek headlight designs. Probably not that good at night, though.

In '57 some automakers designed 4 headlight systems but in some states there were laws forbidding anything beyond 2 lights. It didn't take long for those laws to get changed and soon 4 became typical outside of trucks and cheaper cars. Rectangular headlights started showing up on higher priced cars in '76 from what I've seen.

Another little oddity: halogen sealed beams aren't really one big bulb, just a glass bulb with the halogen bulb attached in the middle. Many, maybe most, now use a plastic shell and lens. Cheaper that way, I guess.

[compu_85]

Most current sealed beams are also total garbage, made with molds that wore out in the 1990s. On the small round lights, old stock, non halogen ones are generally better than the junk Sylvania ones you can buy at AutoZone today.

Wagner did just start selling sealed beams made on new molds. I noticed them in Chevy vans on my way into work. If you pay attention to headlights you can't miss them... they have a cutoff and beam control! And like all good lights, the lens of the fixture doesn't look bright, the bright spot looks like it's behind the lens.

-J

[dieseljeep]

Originally Posted by MadMan

The requirement for sealed beams dates back to the early days of electric light. Cars (if you were lucky enough to have that new-fangled electricity on your car!) used to have a small light bulb inside a big lens housing, just like today. But because of light bulb technology being rather poor back then, the filament burning off would blacken the inside of the glass bulb and it would make very little light, which would be very dangerous to drive at night. Especially since halogen lights were not a 'thing' yet. So for safety's sake, the government said you need to use sealed beam lamps, because the filament is in such a large space, that when it blackens the glass, it would only be a small part, and would still emit enough light to be safe.

Of course, light bulb tech was probably good enough by the 50s or 60s to not warrant this anymore, but it's just one of those laws that stayed on the books for too long a time. By the late 80s, the regulations were changed. Some new trucks still use sealed beams, probably just because they're easier to manufacture - and the carmaker does not need to have a headlight design approved by the Department of Traffic (DOT).

My 2006 Jeep Wrangler still uses the large round headlights like were used in the '50's when the car manufacturers went to 12 volt. I guess they wanted the authenticity of the earlier models. Some of the 80's models, they went with the rectangular type that some of the others used. much to the dismay of the Jeep purists.

[Telecolor 3007]

Oh, 'Jeep' Wrangler. Around 1998-1999 I've rode in one and wonder how could we go so fast when where doing 50. Well, after a time I realized that where doing 50 miles per hour, not 50 kilometers per hour.
And it had automatic gearbox. I thought 1, 2, 3 represnted the gears that you wanted to engage.

[Electronic M]

Originally Posted by Telecolor 3007

Oh, 'Jeep' Wrangler. Around 1998-1999 I've rode in one and wonder how could we go so fast when where doing 50. Well, after a time I realized that where doing 50 miles per hour, not 50 kilometers per hour.
And it had automatic gearbox. I thought 1, 2, 3 represnted the gears that you wanted to engage.

Most automatics have a low range and or a way to force a single gear for situations like being stuck in snow or mud or climbing or descending very steep hills...in most normal conditions 1, 2, 3 or Lo are not selected. Some people will manually shift through the gears of an automatic to check for damaged gears, or to try and launch faster (drag racing automatics are often designed to be used this way).

[Telecolor 3007]

I don't know so much about auomatics. I think I only raided in 2 or 3 automobiles that hat automatic gearboxes (I rode automatic gearbox buses too, but they are different).

I wonder how did this taximeters worked (early on when I took another look on the site I've noticed they also had the picture of one used in Romania): http://www.fama.hu/index.php?mn=28&o...US-tegtlgsLBFo
The had a magentic stuff mounted on the axle like at the speedometer and then an electric cable camed or it was a far more complicated sytem.
What a mecahnical wonder inside: https://www.youtube.com/watch?v=UkahxS2HoZo

[MadMan]

I believe the old mechanical ones would connect to the car's speedometer cable. Not sure about the newer ones.

[Telecolor 3007]

True they where connected to the speedometer: https://www.youtube.com/watch?v=n-Ib5efaw64
Now I have to find out what that cable connection did and how speedometer cable works.

[compu_85]

Speedometer cables are driven by the output of the transmission. The cable spins, and rotates a magnet in the speedometer. It works a lot like a voltmeter... faster rotation makes more force and moves the needle further against the clock spring.

Cars with mechanical speedos, but with cruise control, will have an impulse sensor someplace... either on the back of the speedometer or in a little box in line with the cable. Then the cruise control unit counts pulses.

Electronic Taxi meters work the same way On newer cars they just tap into the vehicle speed signal.

Regarding selecting gear ranges in an automatic, that will do different things depending on the car.

In the 2003 F350 we had, the shift pattern was PRND321. From a stop, if you shifted into 2, the truck would move off in 2! And if you shifted into 3, it would move off in 3! Nice to have that control. It had a "5" speed automatic. Technically, it could make 6 different ratios: It was a 3 speed with an overdrive on the end. But 2 of the ratios ended up being very close. The "2" gear was actually 1st + overdrive, and 3 was really 2nd.
As the truck was warming up it would shift 1, 1OD, 2, 2OD, 3OD; when warm it would shift 1, 1OD, 2, 3, 3OD. 2OD was slightly shorter than 3, so it made the engine run 200 rpm or so faster.

In a friends 76 Mercedes, the shift pattern is PRNDSL (Drive, Slope, Low). It's a 4 speed automatic, but it moves off from a stop in 2nd in drive. If you shift into S / 3, it will move off in 2nd and then shift to 3rd only. If you put it in L / 2, it will move off in 1st, then shift to 2nd. From a stop in D, if you floor it it will kick down to 1st as the car starts moving.

In another friends 85 Mercedes, the shift pattern is PRD32. When you come to a stop in D, the transmission actually rests in 2nd gear. As you touch the accelerator, before the throttle opens, the transmission kicks down to 1st gear so you move off in 1st. This makes the car "pull" less as you're sitting at a light.

Some 78-80 Mercedes accomplished the same thing, but in a more rube goldberg method... they had a small computer box that read the pulses coming from the cruise control pickup, to know when the car was stopped. It looked at the brake light switch too. Like my friends 76, the transmission rests in 2nd gear in D at a stop. But the little box would look for the brake lights turning off after the car was stopped (ie, you took your foot off the brake), and energize the kickdown circuit to shift the transmission into 1st.

-J

[Telecolor 3007]

And classical taximeters workes with that cable too?
How hard it was that adaptation?

[compu_85]

I'm guessing they had the drive cable go up to the meter, then out from the meter to the car's speedometer.

Not too hard, but you'd need specialized gears, and cable ends.

[Telecolor 3007]

And the cable spined or?

[compu_85]

A speedometer cable has a thick outer casing, and an inner part that spins.

Here's some info from the Mk2 VW Service Manual:

http://eva2.homeip.net/eva2/BD01/ch4.1.1.html

The drive gear has a different number of teeth depending on the final drive / differential ratio of the transmission. This results in the same number of rotations of the cable for all transmissions.

-J

[MadMan]

Originally Posted by compu_85

In a friends 76 Mercedes, the shift pattern is PRNDSL (Drive, Slope, Low). It's a 4 speed automatic, but it moves off from a stop in 2nd in drive. If you shift into S / 3, it will move off in 2nd and then shift to 3rd only. If you put it in L / 2, it will move off in 1st, then shift to 2nd. From a stop in D, if you floor it it will kick down to 1st as the car starts moving.

We call that the rabbit gear. It's completely stupid if you ask me. Most Mercedes all the way up into the 2000's start in 2nd, and are designed to do so. I've yet to find one that actually shifts to 1st when you pull off. They all start in 2nd and only drop down to 1st if you really gas it.

This leads to people thinking they have a transmission problem, and - quite frankly - making Mercedes cars really unpleasant to drive. Because even one with a big v8 feels like it has no balls.