On Topic: Driving on a cold engine
Discussion
I know that thrashing the nuts off an engine when it's cold is a bad idea because the oil isn't thin enough to do it's slippery thang etc etc.
My question is this: Even if I change gear at 3/4000rpm, can I damage the engine by pushing it hard at low revs, or is it a simple case of high revs + cold engine = bad, everything else is OK...?
My question is this: Even if I change gear at 3/4000rpm, can I damage the engine by pushing it hard at low revs, or is it a simple case of high revs + cold engine = bad, everything else is OK...?
On mine I have been told to keep it below 2500-3000 for a good few miles if I want to get the best out of it. Something to do with not just the oil but the components reaching the right temp before letting loose. ie all expansion of parts etc reached together. As for using the low end grunt, that wasn't mentioned.
>> Edited by jmorgan on Thursday 3rd April 20:45
>> Edited by jmorgan on Thursday 3rd April 20:45
I was always taaght to keep it lower than 3000rpm until the water temp at least warms up, after this the block warms more swiftly so the oil is going to be at nearly operating temp too - beside most modern cars have no oil temp gauge so water temp is the only indication you get.
I don't think wide throttle openings have a wear effect on an engine directly, but it seems reasonable to me to assume that flooring a cold engine will result in some unburnt fuel etc going out through the exhaust. Generally a freezing block will burn the fuel in a less efficient manner than a warm block - this can in turn cause wear to injectors et al. So maybe it does wear the engine in a way.
The quickest way to warm an engine though is to set off and get it working under load, rather than my tosser of a neighbour who warms his car from freezing by revving it to 5,000rpm from cold, at a standstill until presumbly his heater works and he moves off... Apart from being fecking annoying to us people having to listen to this, but you can actually hear teh engine screaming its mercy!!!
Igiot!! :shakeheadsmiley:
I don't think wide throttle openings have a wear effect on an engine directly, but it seems reasonable to me to assume that flooring a cold engine will result in some unburnt fuel etc going out through the exhaust. Generally a freezing block will burn the fuel in a less efficient manner than a warm block - this can in turn cause wear to injectors et al. So maybe it does wear the engine in a way.
The quickest way to warm an engine though is to set off and get it working under load, rather than my tosser of a neighbour who warms his car from freezing by revving it to 5,000rpm from cold, at a standstill until presumbly his heater works and he moves off... Apart from being fecking annoying to us people having to listen to this, but you can actually hear teh engine screaming its mercy!!!
Igiot!! :shakeheadsmiley:
I thought the danger was of a "cold seizure" rather than wear. I agree with Agent 006 - when you nail a cold engine, the pistons (which are small, made of aluminium and right near the hottest bit) expand rapidly and can stick in the cast iron bores which are surrounded by cold water and won't have had the chance to expand. That said you need to be a real animal to do it - frosty morning and bounce it off the rev limiter as soon as you turn the key - even then it's rare. If, like me, on the other hand, your engine's got 185000 miles on it, you'd be pretty glad if the pistons ever got anywhere near the bores under any circumstances!
I'm sure all the stuff about oil warming up is also important and I'd never work a cold engine hard (by which I mean a combination of high revs and big throttle openings).
I'm sure all the stuff about oil warming up is also important and I'd never work a cold engine hard (by which I mean a combination of high revs and big throttle openings).
I've found that generally the oil will warm up before the water, so if you don't have an oil temp guage its safe to say that if the water is up to temp then so is the oil.
Its been said before but you should drive a car under load to warm it up just letting it idle to warm isn't enough, although the water and oil temps will come up to what you might expect the crankcase and the lower cylinder walls of the engine won't reach proper operating temps.
Its been said before but you should drive a car under load to warm it up just letting it idle to warm isn't enough, although the water and oil temps will come up to what you might expect the crankcase and the lower cylinder walls of the engine won't reach proper operating temps.
Hmm not sure any road car is likely to have problems with component tolerances during cold starts.
Probably an outdated notion from when cars used to detonate as par for the course. Even turbo's, once the oil has reached the bearings with sufficient pressure (i.e. about 2 seconds after ignition) you can thrash it from cold with a modern oil. Not with pig fat mind, tried that - didn't work.
Probably an outdated notion from when cars used to detonate as par for the course. Even turbo's, once the oil has reached the bearings with sufficient pressure (i.e. about 2 seconds after ignition) you can thrash it from cold with a modern oil. Not with pig fat mind, tried that - didn't work.
interestingly - ive heard that leaving the choke out, rather than providing more fuel and hence more heat to warm the engine, actually works as a cooling mechanism and so it takes longer to warm an engine up. can anyone confirm this or is it top fuel dragster lore? personally ive found in all my cars that they warm up quicker when driven - well, when my thermostats working ok - which it isnt 
but thats a little irrelevant 
its been my understanding that even multigrade oil is more viscous at lower temps and hence cannot get to all the necessarily lubrication sites quite like hot oil can but, conversely hot oil is thinner and may not provide the same affect the thicker oil can so go figure....
the general consensus however seems to be dont rag it when cold an itll last longer.
but thats a little irrelevant its been my understanding that even multigrade oil is more viscous at lower temps and hence cannot get to all the necessarily lubrication sites quite like hot oil can but, conversely hot oil is thinner and may not provide the same affect the thicker oil can so go figure.... the general consensus however seems to be dont rag it when cold an itll last longer.
Right then, so the answer is to warm the engine up before moving off, but don't stand around get under way straight after turning the key. Keep the revs down, but keep the revs up, don't labour the engine...
I used to be told that leaving the engine ticking over til it was warm was wasteful on fuel & damaged the engine but everyone I know lets the engine warm up first.
Guess you just can't win.
I used to be told that leaving the engine ticking over til it was warm was wasteful on fuel & damaged the engine but everyone I know lets the engine warm up first.
Guess you just can't win.
I drive it gently until it has some heat in it (3 or 4 miles), don't accelerate to hard, after all going from 0 rpm to 3000 rpm in an instant is going to put some strain on the engine. As the engine starts to warm I up the revs a bit and drive it a bit harder until it is nice and warm and I can thrash the crap out of it.
I have sometimes wondered if you (Bonce) have a method to warming the car as sometimes you thrash the thing home at 100+ on the private strip of tarmac we use and sometimes you pootle along. I on the other hand tend to pootle then thrash
D.
I have sometimes wondered if you (Bonce) have a method to warming the car as sometimes you thrash the thing home at 100+ on the private strip of tarmac we use and sometimes you pootle along. I on the other hand tend to pootle then thrash
D.
mista weava said: you would be amazed how long the oil does take to warm up. i am not in agreement with the above post with regard to the water oil up b4 the water.
just my twopences worth
weava
I agree with the above too.
Water heats up quickest because it is taking the heat away from the engine - exactly what its there for, which in a cold situation is not what you want. I've got oil and water temp gauges and the water will get to normal way befor the oil has even reached 30deg. Once my car is at normal water temp it takes about 10 mins to get the oil to normal temp. This makes sense because of the fact that when your water temp hits normal its then more efficient for the heat to soak into oil and components.
I ALWAYS wait until the oil temp is up before I go above 3k rpm.
My advice, start the car, let oil pressure build (around 30 seconds to be sure). Get yourself comfy, do your hair and off you go... gently.... Wait 5 mins or so after water temp is normal before you start caning it. Oh and change your oil ever 3k.
Cheers,
JC
I generally start my car and rev it gently two or three times - habit due to having a 1.0 205 which occassionally stalled, then gently pull out of the drive and as I usually have to wait a minute or two to get to the main road - the temperature is usually at a reasonable running temperature. From what I have been told, as soon as the oil temp is rising, the engine is being protected and if you take the first 2 miles gently after that it will be safer to open up more and more. That could be total crap though?!!
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