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Old 07-23-2015, 04:07 AM   #1 (permalink)
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Question Starting and driving away wear?

is it really worth the small amount of fuel saved to drive away the moment you start it? doesn't the engine run dry for a few seconds?

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Old 07-23-2015, 04:24 AM   #2 (permalink)
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There's an oil film to protect until oil pressure builds. The oil pump starts pumping the instant the starter is engaged- even before the engine fires- so oil is flowing fairly immediately. If you have an oil pressure gauge you can see how soon it jumps up; if you have an oil pressure idiot light you can see how soon it goes out.

In brutal cold I think an argument can be made for a moment's idling (under a minute; none of this 20 minute B.S.). By brutal cold I mean below 0 F, not 50 F for you Californians.
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Old 07-23-2015, 07:45 AM   #3 (permalink)
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Brutal doesn't start until 20 below.

But I try not to be brutal to my car so I'll give it a few moments when it gets near zero- I'll buckle up and get the music going while the engine's running.
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Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 07-23-2015, 10:19 PM   #4 (permalink)
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If the engine is cold it will be in high idle so you can "drive" at slow speeds without even using the throttle. As stated, when it is below 0°f it is a good idea to allow the engine to run for a short time to get things loosened up and fluid moving. Dont forget that the transmission can receive just as much wear in extreme cold.

I regularly start the car and throw it in drive within 3 seconds. Immediately after firing the engine is running too fast imo to put it in gear.
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Old 08-16-2015, 03:25 PM   #5 (permalink)
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I have taken engines apart that have been sitting for year and there is still oil up in the piston rings and in between all the bearing surfaces.
The engine doesn't run dry.
If it takes the engine several seconds to build oil pressure after starting would you rather have the engine spinning at 1500rpms at no load or slam it in gear and slow it down to under 1000rpm?
With no oil pressure, I would want the engine spinning slower.
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Old 08-16-2015, 03:43 PM   #6 (permalink)
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There will be pressure on the bearings and piston rings of an engine, even when it idles.
The compression phase builds up tension, and so does the burning in the expansion phase.
So engine wise it won't make much difference if you get moving right away or not, as long as you won't boot it.

The gearbox, not so much. In neutral there are little stresses. But if you be smooth with the clutch and throttle, nothing to fear there. The oil film, whether stale or not, won't break if you don't put too much stress on it.
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Old 01-30-2019, 09:13 AM   #7 (permalink)
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-35F now. Today's idling strategy will be to stay inside and not start any engines.
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Old 01-31-2019, 10:34 AM   #8 (permalink)
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I was only at -5.

Business as usual: move off immediately, bless the grill block once heat starts coming in.
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Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 02-14-2019, 05:46 PM   #9 (permalink)
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Quote:
Originally Posted by Frank Lee View Post
...In brutal cold I think an argument can be made for a moment's idling (under a minute; none of this 20 minute B.S.). By brutal cold I mean below 0 F, not 50 F for you Californians.
1) Decades ago, one guy had the idea to oil flood the oil bearing surfaces of an engine first, before starting the engine.
2) I liked the idea of a low powered electrically heated oil dip stick to keep the oil warm through a cold night. Used an electrical dip stick for some years.
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Old 02-16-2019, 04:40 PM   #10 (permalink)
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The racers use a MOROSO Oil Primer. Op-temp regularpressure fills it. One way valve. At start one “releases” the pressurized oil into the passages. Mechanical pressure gauge will show “safe” or better oil pressure. Now, switch in magnetoes and toggle starter.

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