Is warming up essential from cold start?

[ts1]

@blue

Of course that is a potential danger. But my throttle is not only binary 0 or 1.

The English manual for my Kymco X500 asks only for sufficient time to let the oil lubricate the engine - which takes fractions of second and is very different from warming up the engine.
In the German manual there is an additional advise not to rev beyond 6000rpm while temp gauge indicates cold.

Tell me how long would you like to idle? 1 minute or 1 hour or ...? Why exactly that duration?

[JustWantToRide]

All of the parts are warming and expanding and such whether there is any load on the engine or not.  I can't see any benefit from idling it to warm it for any period longer than it takes for it to accept some additional throttle.  I'm using 0w-40 which flows easily when cold.  I would think that idling my engine for 5 minutes to warm it up before riding is harder on it than starting it and riding it away on whatever throttle it accepts cleanly.  Back when I used to ride CL's, TX's and such I took longer to start riding because they wouldn't accept throttle input for longer.  My feeling is that if it accepts throttle then it is time to go. 

[Portland Steve]

Start it up and by the time you have put on your helmet and gloves, you should be ready to go.
The engine will not get fully warmed up for ten to 15 minutes of driving, which you can feel in the power.
I have to say that initial power from a cold start is better on my Super 8 150 than my previous Vespa ET4.
I love the automatic choke!
I have never seen any benefit to letting the bike idle for too long at start and I have had different scooters and motorcycles.
Just ride and don't worry about it so much. 

[axy]

Start it up and by the time you have put on your helmet and gloves, you should be ready to go.

This is what I do, minus the helmet.
So, helmet is on, I start the engine, put the gloves on (15 seconds), roll the scooter backwards for 10 meters (5 seconds), both at home and in front of the place where I work) and off I go.

At that point, the oil is all over the engine. I do not rev it high for a few kilometers.

[blue]

Is there some magic property of warmed up oil that diminishes that "pressure", so parts can handle it?



In some way if you keep your scoot in a shed keep a 100 watt light buld next to the motor but yet far enough so gas or oil wound trip on it. that well keep the engine block worm for easy starting.

[Peters]

Regardless of whether you have synthetic or petroleum oil it takes at least 30 seconds for the oil to reach all parts of the engine. Especially with a 4-stroke.

All of the parts are warming and expanding and such whether there is any load on the engine or not.  I can't see any benefit from idling it to warm it for any period longer than it takes for it to accept some additional throttle.

I agree.

 You still don't want to put a lot of load on the engine as different parts exchange heat at different rates. If one part heats faster than another it expands and the clearance is reduced.

[Peters]

In some way if you keep your scoot in a shed keep a 100 watt light buld next to the motor but yet far enough so gas or oil wound trip on it. that well keep the engine block worm for easy starting.

You're wasting more energy with the light bulb than to just let it idle for 4-5 minutes

[axy]

I would suggest to some forum members to study a bit mechanics and basic thermodynamics, for example, what Saybolt Universal Second is.

It would take 30 seconds for oil to flow through regular 4-stroke engine if SAE30 mono-grade oil was used at -30 C...

[Peters]

http://www.kc-synthetic-oil.com/easier-engine-cold-start.html

Your right I don't know anything axy. I've never rebuilt engines. I've never takin automotive classes. I'm not going to school for mechanical engineering. KIss my thermodynamic ass. So maybe it doesn't quite take 30 seconds but what's an extra few seconds to be sure.

[Peters]

Oh, and for those who don't like to read. Just skip to the part where it says quote: "Considering that up to 60 percent of all engine wear occurs during cold starts, this immediate lubrication is essential to long-term engine life."

[ts1]

Regardless of whether you have synthetic or petroleum oil it takes at least 30 seconds for the oil to reach all parts of the engine. Especially with a 4-stroke.

I can't imagine 30 seconds with a scooter engine. Of course with ship engines. But that's the difference between 3cm and 3m stroke, an engine designed for uncountable cold starts and an engine which is rarely completely stopped.
Some oil always rests in bearings, pipes and pockets. You can open an engine which was untouched for months and there will still be oil everywhere. There is a signifikant difference (10% and more) between the amount needed for the first filling and following oil+filter changes.

[Peters]

Okay, okay. My 30 seconds for the oil was a little exaggerated. The point is it does take time. And no way is it okay to run a cold engine at WOT right away. Everybody knows different metals expand at different rates. That's why engines with cast iron blocks and aluminum heads typically blow head gaskets easy.

[blue]

You're wasting more energy with the light bulb than to just let it idle for 4-5 minutes

True you are. But from what I have been reading everyone wants to just jump on it and ride.
its just a nature way of life to let any motor worm up befor takeing off.Just like geting out of bed
do you just spring up as soon as your eyes open. .......jjjjjust    saying.

[zombie]

I have commented this many times on the forum. This was very true 40 or 50 years ago, especially with mineral mono-grade oils of lower quality.
Nowadays, good semi-synthetic 10W-40 oil has the same lubrication (flowing) characteristics at -30 C and +130 C, so warm vs. cold oil is not an issue anymore.

The biggest problem is the time it takes for the oil to reach all parts of the system after initial cranking, and this is why manufacturers have started adding "stickiness" additives, usually magnesium based,so enough oil "clings" to various moving parts of the engine until fresh oil flushes everything upon start. I know that for car engines, it can take 10-12 seconds for the sump oil to flow fully through some large engines during cold start, and it is probably just a few seconds for small scooter engines.

I am aware you said that this topic is valid for those "anally retentive", so I am just broadening the perspective, and my opinion is that oil flow during cold start with good quality oil of modern oil companies is not a serious topic. It surely was in 50's and 60's.

It is true that the engine part dimensions change with change of temperature. Temperature expansion coefficient of aluminum is, for example, roughly double the TEC of cast iron. Considering that engines operate in temperatures between -30 and +120 C (extremes), parts are not made to be perfect fits, but certain tolerance is calculated and oil, gaskets, O rings etc. are used to fill the gaps and provide compression. It would be, in fact, very difficult to comment if the engine runs better in terms of parts fitting "better" when cold or warm. This may sound like a paradox, but engine is a collection of connected bits that are worn differently, therefore gaps are different in different parts, and these gaps increase as the engine ages. It is true that thermal expansion (warm vs. cold engine) might make up for some of that wear, but new engine is not fitted to be "tight" either. Really, the system is too stochastic to draw any definitive conclusions about this.

However, undoubtedly, engines that reach working temperature of 90 C run the best and wear the least and it is only logical to reach that temperature using the engine in moderate rev range and driving, and not wearing it while it is stationary, and then wear the engine by using it (driving it).

That is EXACTLY what I said... In less words tho~

[zombie]

Is there some magic property of warmed up oil that diminishes that "pressure", so parts can handle it?

The worst of the witches.... The Evil Ethanolllllll. No not really.