Warm Up Time / Oil Temp - When is it ok to cut loose?

[logger]

There is no requirement to warm up the engine on a jet aircraft because they are turbine engines. A completely different scenario to piston. On piston aircraft you MUST wait for the oil temp the get into the green band on the gauge prior to takeoff.

Nah mate. you should know better than that.

RB211 Engine warm up requirements (before takeoff)
-when engine has been shut down for more than 1.5 hours: run engine for at least 5 minutes
-when engine has been shut down for less than 1.5 hours: run engine for at least 3 minutes
-use a thrust setting normally used for taxi operations
-engine oil temp must be above the lower amber band before takeoff

I know from experience that with cold turbine engines in cold ambient conditions you can get oil filter bypass activating until the eng oil warms up. Of course some operators may not choose to apply the manufacturers recommendations

[gerhard]

The relevance is the rate of expansion of the piston comared to the metal around it.

2 stroke vs 4 stroke is no different in that regard, a sump full of oil vs oil in the fuel is also a non-issue.

Yes it's probably more dramatically evident in a 2 stroke that can rev to 22,000, but the fact is the pisron expands faster than the surrounding metal. Just like in your 4 stroke with a sump full of oil that only revs to 7000 or so, which can also destroy itself when overheated.

[Transporter]

When you put a liquid under pressure between two surfaces close together it spreads out and holds those two surfaces apart, if you hold those surfaces a long way apart and squirt a liquid between them it simply flows out along the route of least resistance, by doing that it can't hold the surfaces apart effectively.


That IS basic physics (surface tension of liquids + thermal expansion of metals)

I won't argue any further as everyone applies their own knowledge to any problem presented and make their own decisions on what to accept as correct, but it's always a mistake to presume the knowledge of others.

Hmm..., for that occasion we have additives in the oil.

Besides, everyone of us is warming up engine properly, anyone who drives on public roads is warming up engine in the way that is sufficient for the engine to last looooong time, unless he really stole the car. Just as well that we're in Australia, I can't imagine guys for how long I would have to be warming that engine up during winter in country like Canada?



I suppose that every one of us has different perception to what does it mean to drive gently or fast from cold.

[dave_r]

If you spend $45K on a car, drive it how you like, but anyone who thinks it isn't damaging it to flog it cold is kidding themselves.

I will do what I like as I have on all my previous cars, but after a start up in the garage, backing out, leaving the court and getting around a few corners, its plenty ready for a thrashing. Just avoid me on carsales if it's an issue.

I've lost count of the number of cold siezes I've seen on the kart track - bozos leave the pits with a cold engine and hit anything from 10,000 to 18000rpm (depending on engine type) by the first corner.

I never thrashed my watercooled rotax until it was at the right temp, but not the same thing as a Golf engine!

[gerhard]

I never thrashed my watercooled rotax until it was at the right temp, but not the same thing as a Golf engine!

Same here - the Rotax stayed below 10,500 until it was warm enough - at Oakleigh about 2 laps was enough. Still a lot of revs, but the nikasil barrel coating and the relatively slow revving rotax helped prevent those engines from seizing. The RESA was probably the worst for cold-seizing but gave more thrills than the Rotax Max. The Rotax would stop accellerating by DPE corner, whereas the RESA kept going till time to brake

Different to the Golf engine - I still say no different. Theyre both piston in bore compression engines which get hot when running.

Another reason not to thrash when too cold is the mixture the ECU feeds in - even though the GTI runs pretty rich AFR all the time, it still runs richer when cold. This provides more unburnt petrol to wash that oil off the side of the bores.

[Preen59]

Aeroplane engines have propellers, this gives them a load straight away. Poor wording on my part.

Rotax engines are almost impossible to cold seize- They have a chrome bore. Half a lap and they're good to go. I raced karts for 10 years (stopped racing in '07). I have been involved in tuning/development and building (along with blueprinting) engines for one of the best engine builders in Australia for the last 8 or so and that is ongoing.

Every class i raced, without fail, the engine would be good to go after one lap. And i still lean on an engine straight out of the gate. I never, ever had a cold seizure. Nor has anyone else i have ever seen doing that. The only engines i was ever wary of were RESA's, piston ports and higher. Because of the large fin area and iron bores, they could be susceptible to cold seizure. A quick choke into the first corner on the start of the second lap to give it a mild quench and get some more oil into the bottom end fixes that. People that think they need 2 laps are either too scared to drive on cold tyres or kidding themselves.

[hooba]

Preen - the morning REX flight from Sydney to Orange loads the passengers, and then they fire up the engines and go through a warm up routine for 5-10 mins before the plane even moves, and QantasLink turboprops do the same thing for the first flight of the day.

[pologti18t]

Yes it's probably more dramatically evident in a 2 stroke that can rev to 22,000, but the fact is the pisron expands faster than the surrounding metal. Just like in your 4 stroke with a sump full of oil that only revs to 7000 or so, which can also destroy itself when overheated.

I've had a 4 stroke that revs to 18500 and a 750 that revs to 14500. Neither of them seized in a variety of conditions

I always thought that 2 stroke engines had far looser tolerances than a 4 stroke.

Several times mates have told of 2 stroke bike engines siezing when overheated/ oil starvation only to run again once cooled down. Not sure this is as common in a 4 stroke engine

[Preen59]

Preen - the morning REX flight from Sydney to Orange loads the passengers, and then they fire up the engines and go through a warm up routine for 5-10 mins before the plane even moves, and QantasLink turboprops do the same thing for the first flight of the day.

Very true. But my point was that when they warm up a plane engine, the propeller provides the load. This is completely different than trying to warm the engine without a load. (I knew what i was talking about.. Haha.)

I've had a 4 stroke that revs to 18500 and a 750 that revs to 14500. Neither of them seized in a variety of conditions

I always thought that 2 stroke engines had far looser tolerances than a 4 stroke.

Several times mates have told of 2 stroke bike engines siezing when overheated/ oil starvation only to run again once cooled down. Not sure this is as common in a 4 stroke engine

Once an engine seizes, it is quite possible for the piston to separate from the bore once it cools down.. But it's still shot and will need to be rebuilt. It scuffs the bore, damages the piston and sticks the ring in the groove. After a seizure, I've stripped an engine, cleaned up the bore with emery, dug the ring out, cleaned up the piston and ring groove, cleaned up the ring and had it back together for the next heat before.. But it will never be as good again.

[ethosguy]

Aircooled have larger clearences than watercooled, not so much a 2/4 st thing. Large clearances and the emissions they promote are the underlying cause for the demise of aircooled engines. Large clearances are essential buffer to the substantial differential thermal expansion and high differential temps in an air cooled engine. Your Golf R engine is a world leading low emission, close fit engine.

Any siezure is good reason for a disassembly inspection, hot or cold. Some might run but it won't be a healthy thing anmore. *****, my KTM 2st piston is óut of spec after 20 microns (on dia) are gone...and it'll wear those 20 microns in 50hrs of running. That's not even the surface roughness between peak and trough of the tool finish. It's a big bore too so I hardly have to flog it for my yaryars.

In cold places, like Canada, they have engine sump/block heaters...I have experienced an entire fleet of snow cats (12) that would not start, too cold to crank, after less than 75 minuts after parking from full operating temperature because the operators didn't plug them in to the mains engine heater between shifts. It was only -30deg F. But then big ol'industrial diesels aren't F1 so I can't imagine how they could relate?

I'm watching, currently, cold temp (-40 to + 60degC) testing for weapons gimbals because of differential thermal expansion causing cold temperature loading on opposed taper roller bearings to determine design changes. Grease played a role but now with super high end grease it is proving to be mostly about bearing clearance/preload at the moment and service life/performance tradeoffs and implications. Not pistons but still made of aluminium and steel.

VW engineers (or BMW or Ferarri or...) have no clue what they are talking about in their owners manuals...(sic).

When heat treating aluminium a rule of thumb is about 30 mins per inch thickness for thermal lag. Have a think about the wall thicknesses and conduction paths in an engine? Sounds like the emprical 5-10mins moderate use is about right.

Why do most watercooled engines have thermostatic coolant head/block recirculation control before allowing the cooling system into play?

This just gets more and more entertaining.

[rs73]

sometimes in traffic my oil temp can go to about 97-98C... is that still ok? that's according to the MFD, not sure how accurate it is

[Brian]

I'm struggling here guys. I've read TFM backwards, tried every combination of MFD displays, but I cannot seem to get a readout of oil temp on my MFD (118TSI). Is it not applicable to the 118 or am I missing something?
All helpful criticism will be absorbed with thanks.
Brian

Any help here guys?
Thanks in advance

[OraQube]

Any help here guys?
Thanks in advance

Pretty sure the MY09's can't show the oil temp on the MFD.

[Transporter]

I'm struggling here guys. I've read TFM backwards, tried every combination of MFD displays, but I cannot seem to get a readout of oil temp on my MFD (118TSI). Is it not applicable to the 118 or am I missing something?
All helpful criticism will be absorbed with thanks.
Brian

In our Tiguan I can set up in MFD what you want to have on display - just scroll and press OK on every option that will take you to sub menus, until you find option what you want to have displayed. I don't have the car here (my wife's daily ride) or manual so I can't give you better instructions.

But maybe it is not a feature on your car - which I doubt it.

[Brian]

Pretty sure the MY09's can't show the oil temp on the MFD.

Many thanks to all who replied. I think this may be the case with the MY09 TSI. I'll stick to the coolant temp for my warm up regime.
Regards,
Brian