Engine warming : philosophical question
Discussion
I've got my Tuscan MK2 back from the dealer after 1000 miles service and it runs fantastic.
Now I may gradually rev up to 4500-5000 RPM.
This minor detail together with the nice weather and some time off .....
One QUESTION: Is it correct to say that under theoretically the same ideal conditions a Speed Six engine is better when it takes longer to warm-up?
Why, the faster it reaches 70°, the more friction-forces (pistons, oil-quality, mechanical movements, ....) are generating heat, so it runs less smoothly.
Or .... Is it possible that I'm vomiting total nonsense?
Koen
J_S_G: What is your opinion?
>>> Edited by engelborghs on Friday 18th March 17:18
Now I may gradually rev up to 4500-5000 RPM.
This minor detail together with the nice weather and some time off .....
One QUESTION: Is it correct to say that under theoretically the same ideal conditions a Speed Six engine is better when it takes longer to warm-up?
Why, the faster it reaches 70°, the more friction-forces (pistons, oil-quality, mechanical movements, ....) are generating heat, so it runs less smoothly.
Or .... Is it possible that I'm vomiting total nonsense?
Koen
J_S_G: What is your opinion?
>>> Edited by engelborghs on Friday 18th March 17:18
My opinion: spend less time thinking, and more time driving. 
My opinion's the last one you want on this - I'm just a numpty that drives too fast and kicks up a fuss when the engine goes pop.
Here's my real thoughts (which could also be complete nonsense-vomit):
Once everything is at ideal temperatures (given driving style at that point being equivalent), everything should be equal. Getting up to that temperature is where the majority of the wear/issues/risks are. You've got probably three major ways of warming a car up:
1. Start the car & leave it there to idle up to temperature
2. Start the car, and bounce it off the limiter through the gears until it hits operating temp, then keep doing the same
3. Warm it up gently
So, which do you think is the best option?
Seriously, though...
(1) is a crap option - the gearbox, etc. won't have warmed up right, you'll be running a hot car on cold tyres and be more liable to have an accident, same with brakes, etc.
(2) is an equally bad option... you've got the square law applying to forces involved in the engine - for every doubling of RPM, you've got 4 times the forces (wear). So, the difference between 800RPM & 6400RPM (useful figures to use as the maths is easier) is 8x the RPM, but 32x the wear.
So, the question to ask is does the car heat up at 32x the rate if you really give it some, or is it less/more than that? If it heated up at 100x the rate for some crazy reason, it might make sense to, if it heats up 4x as quickly, it clearly doesn't. I'd wager that due to a whole heap of reasons (heat needing to be spread around not just localised, ambient conditions, etc.) that it probably doesn't reach the oil temperature 32x quicker, so therefore it has a negative impact on the car.
So, there's my pseudo-maths/science/engineering (which I won't be offended if anyone picks apart at all, as this is Friday afternoon pub-discussion time as far as I'm concerned). However, being told by the handbook/dealers/mechanics to warm it up gradually is the best evidence I have.
I'm not quite sure of the point you're trying to make here:
>> Edited by J_S_G on Friday 18th March 17:56
My opinion's the last one you want on this - I'm just a numpty that drives too fast and kicks up a fuss when the engine goes pop.
Here's my real thoughts (which could also be complete nonsense-vomit):
Once everything is at ideal temperatures (given driving style at that point being equivalent), everything should be equal. Getting up to that temperature is where the majority of the wear/issues/risks are. You've got probably three major ways of warming a car up:
1. Start the car & leave it there to idle up to temperature
2. Start the car, and bounce it off the limiter through the gears until it hits operating temp, then keep doing the same
3. Warm it up gently
So, which do you think is the best option?
Seriously, though...
(1) is a crap option - the gearbox, etc. won't have warmed up right, you'll be running a hot car on cold tyres and be more liable to have an accident, same with brakes, etc.
(2) is an equally bad option... you've got the square law applying to forces involved in the engine - for every doubling of RPM, you've got 4 times the forces (wear). So, the difference between 800RPM & 6400RPM (useful figures to use as the maths is easier) is 8x the RPM, but 32x the wear.
So, the question to ask is does the car heat up at 32x the rate if you really give it some, or is it less/more than that? If it heated up at 100x the rate for some crazy reason, it might make sense to, if it heats up 4x as quickly, it clearly doesn't. I'd wager that due to a whole heap of reasons (heat needing to be spread around not just localised, ambient conditions, etc.) that it probably doesn't reach the oil temperature 32x quicker, so therefore it has a negative impact on the car.
So, there's my pseudo-maths/science/engineering (which I won't be offended if anyone picks apart at all, as this is Friday afternoon pub-discussion time as far as I'm concerned
). However, being told by the handbook/dealers/mechanics to warm it up gradually is the best evidence I have. I'm not quite sure of the point you're trying to make here:
engelborghs said:
Why, the faster it reaches 70°, the more friction-forces (pistons, oil-quality, mechanical movements, ....) are generating heat, so it runs less smoothly.
>> Edited by J_S_G on Friday 18th March 17:56
nervous said:
sorry JS, you forgot to factor in both the transmogrifier equation and also the latent cheese differential. so close, but so far. best stick to the day job (especially since this is your night job)
Not forgetting the quantum aardvark.!!!
Technically speaking, I would just warm it up slowly and leave the science to the mechanics. You shouldnt go far wrong.
Enjoy.
Di
engelborghs said:
Hé throttle-maniacs and lady Di,
The SIMPLE question was:" two speed-six engines, one reaches 70° after 20 minutes, the second after 30 min. Which one is theoretically the best engine?
Another throttle-junky
Depends on how it reached that temperature.
If the entire mechanics of the car were bombarded externally by some non-destructive microwave beam to heat them all to running temperature, and this took 30 minutes, whilst the other was set fire to, and that took 20 minutes, the time period would be irrelevant, right?
The point I was trying to make originally was that the act of warming it up quicker may well be destructive if the sqaure law on stresses doesn't also apply to heating it up.
If you could drive two cars in an identical manner, and one just "happened" to reach running temp 10 minutes quicker, that one would have suffered less wear in the process. But to get to that temp quicker, some factor must be different.
So you think, the faster an engine reach running temp, the 'better' it is?
I would "speculate" the opposite because there are more heat/stress generating factors.
If you could drive two cars in an identical manner, and one just "happened" to reach running temp 10 minutes quicker, that one would have suffered less wear in the process. But to get to that temp quicker, some factor must be different.[/quote]
I would "speculate" the opposite because there are more heat/stress generating factors.
If you could drive two cars in an identical manner, and one just "happened" to reach running temp 10 minutes quicker, that one would have suffered less wear in the process. But to get to that temp quicker, some factor must be different.[/quote]
engelborghs said:
So you think, the faster an engine reach running temp, the 'better' it is?
I would "speculate" the opposite because there are more heat/stress generating factors.
No... what I was saying was that if there WEREN'T more heat/stress generating factors, then it would be better to get there quicker. If there are such factors, then it would depend on whether the detrimental effect of the factor was outweighed by the decreased time at sub-optimal temperatures.
In the real world, I'd agree that the faster it reaches running temperature, the worse (as there WILL have been additional stresses to cause this, and they likely WILL outweigh any benefits). In the theoretical world, as I said, I'd point some microwave-beam at it, and heat up the materials at a molecular level without any nasty metal-on-metal grating, which would clearly be better for the car.
>> Edited by J_S_G on Friday 18th March 20:22
listen kids, you just leave the science to me. im the only one even remotley qualified (got my own stink bomb set and everything). you have been warned. no good coming crying to me when youve burnt your eyebrows off with your microwave warming rays.
i have a feeling that was a microwave warming ray on ebay last week. my missus bought it to straighten her hair (which isnt curly in any way). Its currently in my way, everywhere i go, but as yet unused.
i have a feeling that was a microwave warming ray on ebay last week. my missus bought it to straighten her hair (which isnt curly in any way). Its currently in my way, everywhere i go, but as yet unused.
If one engine takes significantly longer to warm up under the same driving conditions, I would suspect the 'slow' engine has a faulty cooling system or oil cooler. I don't think differences in friction etc between an excellent engine and a scrapper would make enough difference to be noticeable, but a duff stat is a distinct possibility and could make a big difference.
On the warmup procedure, I think of it as a mini running-in process. You want to treat it with kid gloves when it is stone cold, but gradually extend the rev range and bursts of throttle until it is up to temperature. The oil takes significantly longer to warm up than the water, when the water is up to temperature you're half way there.
On the warmup procedure, I think of it as a mini running-in process. You want to treat it with kid gloves when it is stone cold, but gradually extend the rev range and bursts of throttle until it is up to temperature. The oil takes significantly longer to warm up than the water, when the water is up to temperature you're half way there.
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