Idling on cold start is bad??!!!??!!

[dom14]

Hey Guys,

I've been believing the few minutes of warming up of the engine on idling rpm is good for the longevity of the engine bottom end, when cold starting.

Here it says otherwise.

http://www.businessinsider.com.au/do...-winter-2015-2

http://www.businessinsider.com.au/he...ot-good-2016-1


Can we please start a conversation about the validity or these two claims?

So, it is an old wives tale or is it not?

Or is it something that is different from engine design to engine design, not a "one size fits all" situation??!!!

[macca]

And I always thought it was about getting the engine oil flowing and warm so as not to cause unnecessary wear.

They warm up aircraft motors don't they? Wonder why?

Imagine hoping in a helicopter, starting it from stone cold and taking off straight away.... just doesn't seem right to me.

Used to race a water-cooled go-kart, never started a race until we had warmed them up pre grid then a few laps of the circuit, never blew one up either!

[AB]

It is true to a degree most engine wear occurs when cold so ideally you want to reach operating temp relatively quickly without putting stress on the engine.

[mudnut]

Yours and mine are have a carby and are fitted with the Thermal Vacuum Valve, which is open to atmosphere while cold. This does two things: It stops the engine advance and also makes the engine run rough at idle, just like a vacuum leak. I have fitted a manual choke, though. In the morning, I have to start the car, drive it through a gateway, get out, close the gate, hop back in and drive down a hundred metre driveway before I get to the highway. The engine still carries on like a pork chop and I use the hand throttle to bump up the revs a bit while the choke is still on. After I drop it into fourth or fifth, I open the choke and let the hand throttle off. and the engine is right to go.
All this tells me is that the old RB, needs to warm up before it runs properly.

[the evil twin]

Old technology engines - warm 'em up for a few minutes

New engines - start 'em and after a few seconds drive 'em, the ECU and TCU will do the rest. Ever noticed that you won't get O'drive in many Auto's until after a few minutes.

The oil thing is pretty much an urban myth these days esp due to lubricant technology advances.
The biggest reason in warming up to operating temps is so the engine parts are at design tolerances esp critical in hi-performance engines.
Generally speaking, Aircraft have a very different lube temp control setup so will reach operating temp at idle much, much quicker than a vehicle

[threedogs]

X 2 as above old cast iron motor yes warm them up.

You may remember sharons thread where her Patrol would change gears [auto]. cause she only lived
a min from the freeway and the patrol never had time to warm up and let the ECU know everything
is ok.

FWIW my coolant temp has been down to 9c this winter via the Ecu-talk read out, Ill idle for a minute or to let things
know they are working and drive slowly [no high revs] till its warm

[mudnut]

Old technology engines - warm 'em up for a few minutes

New engines - start 'em and after a few seconds drive 'em, the ECU and TCU will do the rest. Ever noticed that you won't get O'drive in many Auto's until after a few minutes.

The oil thing is pretty much an urban myth these days esp due to lubricant technology advances.
The biggest reason in warming up to operating temps is so the engine parts are at design tolerances esp critical in hi-performance engines.
Generally speaking, Aircraft have a very different lube temp control setup so will reach operating temp at idle much, much quicker than a vehicle

Yep. The old 4wd Corolla injected engine had a cold start injector in the side of the plenum chamber, so it was ready to go almost from start up, once the gauges indicated all was well.

[dom14]

Yours and mine are have a carby and are fitted with the Thermal Vacuum Valve, which is open to atmosphere while cold. This does two things: It stops the engine advance and also makes the engine run rough at idle, just like a vacuum leak. I have fitted a manual choke, though. In the morning, I have to start the car, drive it through a gateway, get out, close the gate, hop back in and drive down a hundred metre driveway before I get to the highway. The engine still carries on like a pork chop and I use the hand throttle to bump up the revs a bit while the choke is still on. After I drop it into fourth or fifth, I open the choke and let the hand throttle off. and the engine is right to go.
All this tells me is that the old RB, needs to warm up before it runs properly.

Thanx for that information mate. I've had no idea you've fitted a manual choke.
What was wrong with the auto choke?
i know it's not bullet proof system, 'cos the auto choke is a bi-metal heater operated electric one, and isn't designed to respond
to engine heat level at all.
Manual one is ok at the hands of somebody like you who knows how to use and also remembers to do that all the time.
Manual choke setup should be better for the engine as long as you remember to close and open the choke each time you cold start the engine.
I've also been thinking on installing a manual setup, then I realized there's a vacuum assisted choke adjustment system(choke breaker) in the Nikki carby that help adjust the choke valve according to level of intake vacuum present, which would be rpm dependent. Mine appeared to be working fine with that choke breaker vacuum assisted diaphragm.
If it starts to give too much trouble with petrol in the future, I will start experimenting with a manual setup.
ATM, I think the choke breaker mechanism & the bimetal electric auto choke appears to be in tune.

[dom14]

Yep. The old 4wd Corolla injected engine had a cold start injector in the side of the plenum chamber, so it was ready to go almost from start up, once the gauges indicated all was well.

Which engine/car is that?

[dom14]

I think not revving it high/hard any engine of any technology/fuel type when cold started is still a valid practice.