Fire and Drive

As you say, in the old days the carburetors - especially the automatic chokes - required that you warm up the engine more than you have to do today.

I believe that with modern cars when you start the car and have oil pressure, you are good to go.

Many of those cars back then would stumble or stall at very cold temperature unless warmed up a little, but if the engine ran well driving off gently probably would not be any worse than letting it sit and idle. But there are other things that are different today than back when cars had points. Lowering the sulfur content of fuel has eliminated much of the corrosion wear to rings that was mostly present when sulfur combined with water vapor during engine warm up. Removing lead from gasoline has also been shown to increase life of engines. The wear cause by lead in gasoline I believe was also mostly blamed on corrosion also.

Probably shouldn't do it now, either.

According to tests done by the SAE that is exactly what you should do to minimize engine wear. What they found is that the amount of wear is related to oil temperature. They found that if you let the engine sit and idle for 10 minutes to get it up to operating temp that would cause close to 5 times as much wear as it would if you drove the car and it took only 2 minutes to warm up. In other words, the amount of time to reach operating temp is mostly what determines the amount of wear. Of course since this is related to friction from cold oil using an oil that reduces friction at low temps will also reduce wear from cold starts. However I think these tests were done at around 10F. I don't think there is anything definitive for extremely cold temps. If temperature is around -25F then you probably should give it about 30 seconds to warm up.

-jim

Dunno what the story is, but my (manual choke) carburated car starts up nicely on the first try in cold weather. It probably didn't do so thirty years ago, which implies something in the meantime has changed and it's probably got more to do with the fuel than the car.

Mind you, around here 20F is considered really cold, and I have no intention of driving to a place where it is -25F.

Human beings should not live in places where temperature drop below about sixty degrees F. You have to wear clothes and stuff. Cold weather is much more detrimental to the driver than to the car.

--scott

Oils are better today too. I can remember a few years ago when they would come up with a new service grade about every year.

jim wrote: But there are

How many of those changes to service classifications had any effect on how oil behaved at low temperatures?

Well, one thing I notice is that even if the engine is warmed up, other things aren't. The power steering system will almost kill the engine if I turn the wheel too hard. Also I have to double clutch every shift for a mile or so because I'm guessing the oil in the transmission is thick enough to almost stop the countershaft as soon as power is removed from it. Granted, many manuals these days are filled with ATF (like mine) which IIRC is approximately 20W. My dad used to tell me stories of when he was in High School in the 1960s in Pennsylvania. During the winters he would have to park his 1957 Plymouth (or maybe it was the 53 Crown Vic) in second gear because it never warmed up enough to be able to shift on the way to school. (Uphill, both ways, etc). I'm guessing those old manuals had 90W in them.

Also there's the joy of breaking the tires loose from the ice, and on some days (like today) all 4 tires have 'flat spots' on them that take a long time to knead out. Some vehicles with small engines but full- sized radiator profiles will actually stay below operating temp while driving. This time of year you see a lot of small trucks (like mine) and vans with the cardboard bungeed to the grille. Nothing like driving for 10 miles, getting off the highway and having your engine return to fast idle when you hit the stoplight.

I agree that living in places like this is completely asinine. I don't know how (or why) people bothered with this before the industrial revolution, and things like fiberglass insulation and gas boilers became available.

A lot of people replaced the automatic chokes with manuals, some years ago, because they could get them to start better that way. Automatic chokes got better with time but, thank God, with modern FI systems we dont have to worry about it.

I dont know if gasoline is any better now. Motor oils certainly are.

"hls" wrote in news:d6KdnaDSaanJc93WnZ2dnUVZ snipped-for-privacy@giganews.com:

Today's gasolines are certainly a lot more volatile than they used to be. That volatility would help with cold-starting.

I cant even comment on it. Essentially all the gasolines of that day used tetraethyl lead or tetramethyl lead as octane improvers. Now none of the US gasolines have them. That might be a clue as to how and why gasoline formulations may have changed.

"hls" wrote in news:gtidnZLlm81GYt3WnZ2dnUVZ snipped-for-privacy@giganews.com:

The only reason I "know" this is because I see it mentioned all the time in the classic car magazines. It seems modern fuels have a tendency to cause vapor lock in classics, which were designed for use with much less volatile fuels.

The "classics" had much lower pressure in the fuel lines than do the fuel injected cars of today. High line pressure counteracts vapor lock (within expected temperature ranges).

We might be able to find some vapor pressure curves of old fuels versus the new formulations, and that should tell a lot.

IME, different cars handle cold differently. But I've experienced variations of what you said with almost every car I've had. Only one that I started and took off right away without warming a bit was the '88 Celebrity 2.8. Nothing phased it. Never had to put cardboard on, though both 4-bangers I've had, a 2.0 Cav and a 2.2 Corsica, took much longer to put heat in the passenger area than a 6 or 8. But the t-stat should keep you from using cardboard. First thing I think when I see that is poor cooling design or no t-stat. Some backyard mechanics used to throw the t-stat away to keep from overheating in the summer. Until it warmed up, the '64 Bug would want to creep forward in neutral unless you disengaged the clutch. 90W. But that one never warmed up the inside when it was bitter out. Had to keep an ice scraper inside to scrape the *inside* of the windshield as I drove. Bitter is south of -0 F to me. Worse thing is when I've heard the rings scraping the cylinder walls on my 350 with a dead cold start-up at -27 F. Very bad sound. Ran straight 30 weight oil then. Heard a lesser noise once with my Celebrity 2.8 running 10-40 oil at

-25 F. Let it run a minute before taking off that time. Always good to park with nose away from the wind if you can. Can make a huge difference in how fast the engine cools. When bitterly cold, I usually take off slowly right away if traffic allows, and find everything loosens up pretty quick. BTW, I never had a problem doing that with carbs either, but my choke, auto or manual, was always set right. This real cold stuff doesn't happen here (Chicago area) as it does up north, but if you're here long enough, you'll run into what I've mentioned.

Jobs, probably. And oddly enough, some people like snow. Since I was born here, it never bothered me when I was younger. Just something you deal with. Now that I'm getting old, so is the cold.

--Vic

My mom owned a 1952 Ford car, six cylinder, manual shift transmission with manual choke.No matter how cold the weather got that car always started right up first time every time.Someday, I am going to rig up a manual choke on my 1983 Dodge van.I hate automatic chokes, worst invention ever, in my opinion. cuhulin

Never had a problem with my auto chokes - all GM cars. But I checked them every year as it got cold. The bi-metallic element changes tension over time, so you have to adjust them occasionally. Only time they're a bit of a hassle is clearing a flooded engine. Have to prop them open. I always used a crumpled cig pack for that.

--Vic

If the choke unloader is correctly adjusted, fully depressing the accelerator should clear flooding, enabling a start. Once started (with the accelerator returned to a [fast, with a cold choke] idle position), a correctly operating and adjusted vacuum break would allow the engine to continue running.

As I recall all my chokes had a positive attachment to the element via the choke shaft, and if the element was cold it would close the choke. Don't know about unloaders or vacuum breaks. Just had a heat tube from the exhaust manifold to the choke element body to warm the element. Only other piece was a link to the fast idle cam. Very simple. Each year when it got to freezing temps I would pull the air cleaner, press the gas to the floor so the choke would close (unload?) then watch it fully open as the engine warmed. I did check an occasional check in really cold temps that it was fully opening as it should, and it always did. And I did notice that after a couple years it wasn't fully closing at my check-up, and I had to loosen the cover to jack it down a bit. Always checked that the fast idle was engaging and that was that. I can't even remember lubing the linkages, but I might have. Distinctly remember that it had to propped open when cold though. Only dealt with clearing a flooded engine a couple times though, so I may have missed something. But I don't miss carbs.

--Vic

The vacuum break opens the choke up just a bit when the engine is started. Some choke housing will have an electric coil or will run coolant through the choke housing to speed up the choke opening. My guess is that this was done mostly on foreign cars. I think the automatic chokes worked pretty spiffy but you had to adjust it to your working temperatures and that's why most folks had problems. Since I live in the tropics, I would set it pretty much open all the way.

The choke unloader is a device (usually cams and a rod) that links the carbs throttle and choke butterfly shafts to one another. In the final few degrees before the throttle is wide open, the choke unloader linkage forces the choke open allowing the engine to purge itself of excess fuel during cranking. When the engine starts, the manifold vacuum operated vacuum break restricts the choke mechanism from fully closing the choke butterfly.

It is remarkable that it started with single grade 30 wt oil. A lot of the noise you heard was probably the oil pump. At that temperature the oil pump can suck the oil in but the oil in the pan won't flow to replace the oil that has been drawn, so you very quickly end up with the pump sucking air thru a hole in the oil. The oil surrounding the hole is too stiff to flow into the hole.

-jim