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Times Have Changed: Cold Starting
On Thu, 20 Jan 2005, Steve wrote:
> > Near universal use of 5W-30 oils and more common use of synthetics. > > (10W-40 used to be the most common oil used). > Nope Actually, Steve, yeah, that is one of the factors in the much greater ease of super-cold starts. You live in Texas. I live in Toronto. That alone makes me more qualified to comment on it than you (which is hardly a fair exchange: You get to have barbecues and mow your lawn in the middle of January, I get to prattle-on about cold starts. No fair.) What's more, I've got direct and recent (last month) experience with the difference oil weight makes in ability and ease of starting an engine from cold. So, shutchyer mouth, you! > Its ALL because of multi-port high-pressure electronic fuel injection Naw, it isn't. That's a major factor, but certainly not the only one. EFI makes newer vehicles much less tricky to start in the very cold, but other factors apply to new and old cars alike. Oils with lower pour points and better cold pumpability, gasolines that burn cleaner (leaving the spark plugs cleaner so they require less arcover voltage), etc. DS |
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Daniel J. Stern wrote:
> On Thu, 20 Jan 2005, Steve wrote: > > >>>Near universal use of 5W-30 oils and more common use of synthetics. >>>(10W-40 used to be the most common oil used). > > >>Nope > > > Actually, Steve, yeah, that is one of the factors in the much greater ease > of super-cold starts. You live in Texas. While I'm sure that the better oils increase cranking speed and allow the engine to start quicker and idle with less effort, I don't think it has anything to do with the sputter/die/restart that everyone used to know about with carbureted cars. I live in Toronto. That alone > makes me more qualified to comment on it than you (which is hardly a fair > exchange: You get to have barbecues and mow your lawn in the middle of > January, I get to prattle-on about cold starts. No fair.) What's more, > I've got direct and recent (last month) experience with the difference oil > weight makes in ability and ease of starting an engine from cold. So, > shutchyer mouth, you! > You can come mow my lawn in January ANYTIME, if you miss mowing lawns so much :-p And maybe you can snort some cedar pollen while you're at it so I don't have to breathe it:-) > >>Its ALL because of multi-port high-pressure electronic fuel injection > > > Naw, it isn't. That's a major factor, but certainly not the only one. EFI > makes newer vehicles much less tricky to start in the very cold, but other > factors apply to new and old cars alike. Oils with lower pour points and > better cold pumpability, gasolines that burn cleaner (leaving the spark > plugs cleaner so they require less arcover voltage), etc. > > DS Again, I don't really disagree, but I don't think any of that has so much to do with start/sputter/die/restart as EFI does. EFI can meter, vaporize, and evenly distribute fuel FAR better at low temperatures than a carburetor can, while at higher temperatures the difference is far less noticeable. Oil thickness, plug condition, and battery power all matter, but those are second or third-order effects compared to the better fuel control from MPEFI. And there's even a noticeable difference beetween low-pressure throttle-body injected cars and moder high-pressure EFI cars in the "cold" weather we get here in Texas, too. TBI cars often gripe and grumble a lot like carbureted cars because the intake manifolds are "wet" and fuel distribution is very poor in cold temps, whereas MPI cars almost never do. |
#3
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On Thu, 20 Jan 2005, Steve wrote:
> While I'm sure that the better oils increase cranking speed and allow > the engine to start quicker and idle with less effort, I don't think it > has anything to do with the sputter/die/restart that everyone used to > know about with carbureted cars. And I'm telling you, from firsthand experience, that you're wrong on this exact point. With 15w50 Mobil-1 at 20 below (C), it took two or three starts for the engine to stay running. With 5w30 Mobil-1 at 20 below (C) and no other changes, the engine stays running after the first start. Cranking speed is pretty irrelevant unless an engine is so whipped that the compression pressure leaks past the rings so fast that a high cranking speed is needed. GM proved in the early 1960s that a typical passenger car engine (of the day!) would start at cranking speeds as low as 6rpm. > You can come mow my lawn in January ANYTIME, if you miss mowing lawns so > much :-p And maybe you can snort some cedar pollen while you're at it so > I don't have to breathe it:-) Fine. I'll accept payment in trips to Kreuz'. |
#4
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In article ch.edu>,
"Daniel J. Stern" > wrote: > Cranking speed is pretty irrelevant unless an engine is so whipped that > the compression pressure leaks past the rings so fast that a high cranking > speed is needed. GM proved in the early 1960s that a typical passenger car > engine (of the day!) would start at cranking speeds as low as 6rpm. Hell, my old, but reasonably healthy, '82 Mazda 626 will push-start in third gear with somewhere between three and five feet of roll - not a "fast" roll, either, although it does fire even quicker if I can get up some serious speed before popping the clutch - just "moving" - *MAYBE* 1 or 2 MPH, if that. In reverse, a foot or so of roll, at *WAY* below typical walking speed, and a quick clutch-bump is all it takes to fire it up every time. Dunno what the effective RPM is in either case (too lazy to do the math) but whatever the number, it's obviously sufficient for this beast Guess that means it ain't quite whipped yet... This saved my bacon one night at about 3 in the AM... Stopped out in the middle of nowhere to watch the Perseid meteor shower dropping something like 80 streaks per minute before continuing on my newspaper route, and when I decided it was time to go, the starter said "Nah, I wanna stay here and watch the sky-show" (Turned out later to be the starter literally falling apart - One of the two long screws that held the end-caps on it had vibrated loose, allowing some flex, which bound the bearings - minor miracle: The screw that fell out dropped into a groove in the engine cradle, where it rode safely until I found it later that day while I was doing the wrenching to change out the starter.) Damn fool me had decided to stop at the bottom of a little valley, or maybe gulley would be the better word, in order to screen out the lights on the horizon that were interfering with viewing the meteors - Great view, but both directions were uphill - Figured I was screwed royally. Grunted and heaved and cussed and sweated, and probably strained something, but finally managed to get the front wheels about 2-3 feet up the forward incline before gravity took over and started pushing me back down the slope. Reached in and set the P-brake, sat down and caught my breath, then turned it on, put it in reverse, mashed the clutch, and released the brake. It started rolling back, exactly as expected. It might have managed to hit the dizzying speed of half a mile an hour by the time I bumped the clutch. The front end was still on the slope when the engine fired up. -- Don Bruder - - New Email policy in effect as of Feb. 21, 2004. Short form: I'm trashing EVERY E-mail that doesn't contain a password in the subject unless it comes from a "whitelisted" (pre-approved by me) address. See <http://www.sonic.net/~dakidd/main/contact.html> for full details. |
#5
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On Fri, 21 Jan 2005, Don Bruder wrote:
> > Cranking speed is pretty irrelevant unless an engine is so whipped > > that the compression pressure leaks past the rings so fast that a high > > cranking speed is needed. GM proved in the early 1960s that a typical > > passenger car engine (of the day!) would start at cranking speeds as > > low as 6rpm. > Hell, my old, but reasonably healthy, '82 Mazda 626 will push-start in > third gear with somewhere between three and five feet of roll My '91 Spirit R/T would reliably start by just turning the ignition "on", putting the trans in "Reverse", releasing the parking brake, rolling a few feet down the driveway, then releasing the clutch. Two compressions was all it took. |
#6
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In article ch.edu>,
"Daniel J. Stern" > wrote: > On Fri, 21 Jan 2005, Don Bruder wrote: > > > > Cranking speed is pretty irrelevant unless an engine is so whipped > > > that the compression pressure leaks past the rings so fast that a high > > > cranking speed is needed. GM proved in the early 1960s that a typical > > > passenger car engine (of the day!) would start at cranking speeds as > > > low as 6rpm. > > > Hell, my old, but reasonably healthy, '82 Mazda 626 will push-start in > > third gear with somewhere between three and five feet of roll > > My '91 Spirit R/T would reliably start by just turning the ignition "on", > putting the trans in "Reverse", releasing the parking brake, rolling a few > feet down the driveway, then releasing the clutch. Two compressions was > all it took. Yep, that's about what it takes with this beast of mine. As soon as one cylinder even half-assed fires, the engine is running, and keeps on running until I turn off the key. I *LIKE* that in a vehicle. -- Don Bruder - - New Email policy in effect as of Feb. 21, 2004. Short form: I'm trashing EVERY E-mail that doesn't contain a password in the subject unless it comes from a "whitelisted" (pre-approved by me) address. See <http://www.sonic.net/~dakidd/main/contact.html> for full details. |
#7
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my OLD DATSUN 66 or so had a HAND CRANK that went through a hole in the
bumber to the fly wheel...hard starting, tired battery, NP even had a "dog" to kick it out after it started.......... opened up some of the "oldtimers" eyes in town, when for chuckles, I crank started it...... it was a bullet proof OLD PICKUP......no comfort, no pep, but was reliable for many miles! even like going mudding.....and easy to find mud here! |
#8
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Have to go with Daniel on this one.. I can remember some research in the
70's having to do with pour points and cold start/running.. and they found at certain temperatures.. they could crank an engine @ 600rpm and it just wouldn't produce enough power to keep itself running with the heavier oils.. darned if I can find a reference to it on the web though.. don't remember who did it either.. but think it was one of the oil companies. |
#9
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Daniel J. Stern wrote:
> On Thu, 20 Jan 2005, Steve wrote: > > >>While I'm sure that the better oils increase cranking speed and allow >>the engine to start quicker and idle with less effort, I don't think it >>has anything to do with the sputter/die/restart that everyone used to >>know about with carbureted cars. > > > And I'm telling you, from firsthand experience, that you're wrong on this > exact point. With 15w50 Mobil-1 at 20 below (C), it took two or three > starts for the engine to stay running. With 5w30 Mobil-1 at 20 below (C) > and no other changes, the engine stays running after the first start. And, your engine has WHAT type of fuel injection? <cough...> I seriously doubt you'd see as great a difference if it were a 93 Magnum 318 instead of an 89 TBI 318. As I said, TBI has a lot of the same cold-weather fuel distribution and vaporization issues that a carburetor does, and the thicker oil is going to aggravate it a lot more than it would an MPI setup that doesn't puddle fuel in the intake. > >>You can come mow my lawn in January ANYTIME, if you miss mowing lawns so >>much :-p And maybe you can snort some cedar pollen while you're at it so >>I don't have to breathe it:-) > > > Fine. I'll accept payment in trips to Kreuz'. > There's a danger to both of us in that: You'd eat all your profits, and I'd eat myself into a BBQ coma :-p |
#10
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Don Bruder wrote:
> In article ch.edu>, > "Daniel J. Stern" > wrote: > > >>On Fri, 21 Jan 2005, Don Bruder wrote: >> >> >>>>Cranking speed is pretty irrelevant unless an engine is so whipped >>>>that the compression pressure leaks past the rings so fast that a high >>>>cranking speed is needed. GM proved in the early 1960s that a typical >>>>passenger car engine (of the day!) would start at cranking speeds as >>>>low as 6rpm. >> >>>Hell, my old, but reasonably healthy, '82 Mazda 626 will push-start in >>>third gear with somewhere between three and five feet of roll >> >>My '91 Spirit R/T would reliably start by just turning the ignition "on", >>putting the trans in "Reverse", releasing the parking brake, rolling a few >>feet down the driveway, then releasing the clutch. Two compressions was >>all it took. > > > Yep, that's about what it takes with this beast of mine. As soon as one > cylinder even half-assed fires, the engine is running, and keeps on > running until I turn off the key. I *LIKE* that in a vehicle. > People who haven't been there to see it don't believe me when I tell them this, but under just the right conditions (warm weather, engine recently shut down, and crank landing so that one cylinder is just after TDC), I can occasionally start one of my cars just by turning the key ON (no starter at all). The spark from the electronic ignition powering-up lights off the mixture in that one cylinder, whcih kicks it over enough to start it. I can pretty reliably get it to "kick" enough to visibly move the crank any time I want, but it kicks backwards about half the time because the piston is BTDC and usually only turns the engine very slightly. But once in a blue moon (maybe twice in the past 20 years) the darn thing will kick forward hard enough to start and keep running. |
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