warming car up to 80 degrees

[LegoHead]

Right, I've heard that you can rag the engine after the temperature hits 80 degrees and it won't damage it.

Is this true, lots of ppl let the engine warm up before going above 3000rpm.

Would it be feasible to mount a temp sensor to correct part on engine to monitor when its "safe" to boot it?

What sort of damage is done, and why before the engine is warm?

 

[White16valver]

I think of it this way: Would you want to be kicked out of bed and made to run like a **** straight away? Or would you like a little time to wake up before starting a gently stroll and slowly building to a run when you've warmed up? LoL

You can tell a car has warmed up by the water temperature, BUT the oil temperature takes much longer. Mine takes at least 10 minutes to get off the bottom of the oil temp scale in town driving. (good thing the valver's got an oil temperature guage )

 

[Rcbuk]

As a rule of thumb, the oil takes twice as long to warm up than the water does.

It also takes longer to cool down which comes in handy

 

[BenR]

with modern oils, once you start up and have oil pressure, there is no metal on metal contact.

 

[theduck]

^^ meaning that you can thrash it from cold? :S

 

[LegoHead]

with modern oils, once you start up and have oil pressure, there is no metal on metal contact.

Thanks Ben, I should've known that, I'm studying for my engineering degree too. doh!

 

[LegoHead]

I think of it this way: Would you want to be kicked out of bed and made to run like a **** straight away? Or would you like a little time to wake up before starting a gently stroll and slowly building to a run when you've warmed up? LoL

Yeh, I have heard of so many ppl dying of heart attack first thing in the morning.

 

[White16valver]

You don't want your car to die of a seizure! LoL

BenR - as per the question above, does it really mean you can thrash it from cold? The valver sounds terribly metallic and like a diesel until it's warmed up...

 

[BenR]

^^ meaning that you can thrash it from cold? :S

Not essentially, if the oil is say 40 deg or from a warm day, then you cna drive normally from the off and not ponce around at 2000rpm worried about damage and metal to metal contact.

If its freezing, you can still drive normally.....but drive normally for that little bit longer.

common sense should be used, i've taken plenty of cars from cold when i was late to be places, doesnt do anything. The only real damage occurs at startup, which is how bmw did their million mile non stop run for publicity, if you have oil pressure, nothing is 'touching'.

 

[BenR]

You don't want your car to die of a seizure! LoL

BenR - as per the question above, does it really mean you can thrash it from cold? The valver sounds terribly metallic and like a diesel until it's warmed up...

You will have tappet response issues on a cold day like today from start on a hydraulic lifter. Pistons also are designed to work with heat in them so thermal expansion rates are taken into account for build clearances, so until they are warm they can sound a little knocky. Plus cold start fueling and roughness doesnt really help.

Put it this way, when i build an engine, the piston clearances i calculate when hot are roughly 1-1.5 thou (thats thousands of an inch)....not much room for error.....but there still int any metal to metal contact. With mains and big ends, again your looking at 1.5-2 thou........and any metal to metal contact will scrap a bearing at any sort of rpm engines run at, so worrying about any contact at all isnt really an issue unless there is a problem.

Obviously if your in scandinavia and your oil is below the pour point, thats a different issue all together. But in our temperate climate, if you running the right oil, i wouldnt worry too much about driving your car.

 

[White16valver]

Ah, ok, cool

I think it just sounds worse than usual because it needs a service and I've just been topping it up with spare stuff from the shed, so it's currently running a mixture of Magnatec and some cheap 15w50.

Not exactly ideal with Zero Degree mornings... LoL :clown:

Roll on the service and some fully synth stuff!

 

[LegoHead]

I think this means I have been driving quite well then, I change early for the first few miles then boot it if the need is there.

 

[White16valver]

Yep, common sense approach is good

Just don't be afraid to boot it when cold if you're in danger suddenly! lol