Running Engine On Turbo Diesel Time Before Turning Off ?

Olley46 · Guru

Running Engine On Turbo Diesel Time Before Turning Off ?

rockylizard · Guru

Gday...

Sticking me head out and will probably attract some barbs .... BUT .... I thought that glazing of bores was caused by letting the engine idle too long when cold because of the manual choke making a richer mixture until warm - particularly with carbies rather than fuel injection. Lengthy idling when at operating temperature was not a problem for glazing bores I thought - coz if ya lived in Melbourne/Sydney/Brisbane/Adelaide/Perth and drive ya car to and from home to work - it will spend HEAPS of time idling in traffic jams for long periods.

Modern engines with their computer controlled injection systems, and no need for a choke, would negate the 'over-rich mixture' for a cold engine. The computer makes sure the fuel/air mixture is altered every couple of micro-seconds.

So, starting the engine and idling for a 'few minutes' no longer causes glazing ... and idling when at operating temperatures will not cause glazing.

Awaiting for correction from those wiser perhaps hmm

And now returning to the original question ... As stated by others above, if operating your vehicle at 100kph, for instance, along the highway and then pulling into a servo, for instance, as you pull into the servo, you will be 'idling' up to the bowser, and then just let it idle for a while before turning it off. I usually let it idle while I take off me specs, get me mobile and stick it in me pocket, adjust me undies, and then turn it off as I am gettin' outta the vehicle. Never been a problem for the many years I have had a turbo diesel.

Cheers - John

-- Edited by rockylizard on Saturday 12th of October 2013 09:14:30 PM

Duh · Guru

Can anyone tell me how long you are supposed to run a turbo engine before switching off please? confuse

Some have told me that if you have just been doing a short run (eg; local shopping trip) you don't have to worry too much about running the engine when stationary before turning it off, but if you have been doing a long run, then about a minute? confuse

I would be interested to know what is the correct thing to do. confuse

Also, if you do not have an automatic shut down device for when you park, lock and leave the vehicle, is it worth fitting one? confuse

Any info appreciated. aww

2weis · Senior Member

if you have been driving in a manner that makes the turbo work then 2 minutes to make sure it has stopped spinning should be ample tims
if you have been driving around most suburban roads at low/normal speeds then you should be able to shut straight down
in qld it is not legal to leave a vehicle unattended with the motor running (i believe)
brian

Duh · Guru

Thanks Brian,

I did see a few farmers etc in Longreach park and leave theirs running, first time I was aware some diesels did that, I thought they had accidently left their engine running somehow, then it shut down on it's own....

Duh · Guru

Thanks Lance, I must admit I usually only wait for 30 seconds before I shut down, mainly because I don't have the patience to wait any longer, I hadn't heard about the glazing before. smile

poppymick · Member

the best set time on turbo timer is 3mins that gives it enough time to stop spinnin and cool dwn
as a ex trucker I always had it set on 3-5 min any shorter time and u can have problemns.

Bunkerbob · Senior Member

I worked for a VERY large transport company with over 200 prime movers and they never used turbo timers. There studies showed that for the amount of fuel they used, and they still use fuel, compared to the number of turbos that go bang, it wasn't worth the effort. I have also been led to believe that if you are doing a long highway haul and stop at a truck stop, by the time you filled your log book in was time enough anyway. If you are in a small diesel, L/C, Patrol, Pajero, etc, by the time you have slowed down for the run into the home or reversed your van in, that is time enough. You only need the pyro temperature to be at normal (200 degrees or less) rather than the 500 degrees while under load. There is also the legal factor of leaving your car running and then walk away.

Olley46 · Guru

Duh wrote:

Thanks Lance, I must admit I usually only wait for 30 seconds before I shut down, mainly because I don't have the patience to wait any longer, I hadn't heard about the glazing before.

Hi Vic
When I said about glazing the cylinders ,only happens with excessive idling like 1 hour plus. Five minutes won't hurt,really only need to idle down when your motor has just been working hard like towing ,or if you have been sitting on 150KMH JOKING ABOUT THE 150KMH,if you had long drive at 110KMH then it would pay to idle her down.

Lance C.

Baz421 · Guru

rockylizard wrote:
Gday...
Sticking me head out and will probably attract some barbs .... BUT .... I thought that glazing of bores was caused by letting the engine idle too long when cold because of the manual choke making a richer mixture until warm - particularly with carbies rather than fuel injection. Lengthy idling when at operating temperature was not a problem for glazing bores I thought - coz if ya lived in Melbourne/Sydney/Brisbane/Adelaide/Perth and drive ya car to and from home to work - it will spend HEAPS of time idling in traffic jams for long periods.
Modern engines with their computer controlled injection systems, and no need for a choke, would negate the 'over-rich mixture' for a cold engine. The computer makes sure the fuel/air mixture is altered every couple of micro-seconds.
Ah stick your head out John,, we area all entitled to.
So, starting the engine and idling for a 'few minutes' no longer causes glazing ... and idling when at operating temperatures will not cause glazing.
Anyway glazing is mainly diesels run at no or very low load,,, thats why you see lights etc on when gensets are running, to give it a load and ensure that cylinder pressures are up and can seal the rings in the bore.
Petrol itself does not glaze a bore but has the opposite effect in that it tends to "wash" the oil off the cylinder walls increase wear, particularly at engine start.
Awaiting for correction from those wiser perhaps
And now returning to the original question ... As stated by others above, if operating your vehicle at 100kph, for instance, along the highway and then pulling into a servo, for instance, as you pull into the servo, you will be 'idling' up to the bowser, and then just let it idle for a while before turning it off. I usually let it idle while I take off me specs, get me mobile and stick it in me pocket, adjust me undies, and then turn it off as I am gettin' outta the vehicle. Never been a problem for the many years I have had a turbo diesel.
Timers to idle the engines of diesels were first introduced, (to the best of my recollection of my training - it WAS ages ago) to lubricate the bearings while the turbo slowed down,,, ie IF you had the turbo spinning at 60,000RPM and turned the engine off, the turbo bearings could be starved of oil.
Older turbos had an oil gallery/reservoir to supply oil in turbo rundown,,, but the later ones had full oil pressure to each bearing/bush.
Cheers - John

-- Edited by rockylizard on Saturday 12th of October 2013 09:14:30 PM

Olley46 · Guru

Bas 421 gooday John you hit the nail on the head,exactly what I was trying to say, I was on the wright track.

Lance C.

Duh · Guru

Thanks for all the feedback and advice folks, it has been very interesting, anyone else want to add anything you are most welcome, it's been a bit of a learning curve for me for sure.... smile smile smile

PeterD · Guru

rockylizard wrote:
Sticking me head out and will probably attract some barbs .... BUT .... I thought that glazing of bores was caused by letting the engine idle too long when cold because of the manual choke making a richer mixture until warm - particularly with carbies rather than fuel injection. Lengthy idling when at operating temperature was not a problem for glazing bores I thought - coz if ya lived in Melbourne/Sydney/Brisbane/Adelaide/Perth and drive ya car to and from home to work - it will spend HEAPS of time idling in traffic jams for long periods.

If just idling an engine glazes it up then there must be a lot of travellers to Qld with glazed motors with all the road works going on up there. I note that not many turn their motors off when waiting at road works.

The following is the relevant section of the Australian Road Rules. Most states have accepted the provisions verbatim.

213 Making a motor vehicle secure

(1) This rule applies to the driver of a motor vehicle who stops
and leaves the vehicle on a road, except so far as the driver
is exempt from this rule under another law of this
jurisdiction.

Note Motor vehicle is defined in the dictionary.
(2) Before leaving the vehicle, the driver must apply the parking
brake effectively or, if weather conditions (for example,
snow) would prevent the effective operation of the parking
brake, effectively restrain the motor vehicles movement in
another way.
Offence provision.

(3) If the driver will be over 3 metres from the closest part of
the vehicle, the driver must switch off the engine before
leaving the vehicle.
Offence provision.

(4) If the driver will be over 3 metres from the closest part of
the vehicle, and:
(i) there is no-one left in the vehicle; or
(ii) there is only a child or children under 16 years
old left in the vehicle;
the driver must remove the ignition key before leaving the
vehicle. Offence provision.

(5) If the driver will be over 3 metres from the closest part of
the vehicle and there is no-one left in the vehicle, the driver
must:
(a) if the windows of the vehicle can be secured secure
the windows immediately before leaving the vehicle
and
(b) if the doors of the vehicle can be locked lock the
doors immediately after leaving the vehicle.
Offence provision.

Note Window is defined in the dictionary.
(6) For the purposes of subrule (5), a window is secure even if
it is open by up to 2 centimetres.

Duh · Guru

Thanks for the copy of the Oz road rules Peter D, it sounds like it would be better not to do it when parked up if you don't want to risk a fine etc. It would be interesting to see what states actually enforce that, don't some later model diesels have the automatic cut out fitted to the vehicle from new? From the other posts it sounds like trucks might have.

Could make for an interesting court case if it only applies to turning off vehicle motors in general, although I suppose they could argue that you just have to sit and wait for it to cut out before you leave the vehicle immediate vicinity.

Peter_n_Margaret · Guru

1. Turbo timers are illegal.
2. The objective of leaving a turbo charged vehicle running for a while before turning it off is to allow the turbo charger to cool down first. If shut down hot it may 'cook' the oil in the turbo and that may reduce the life of the turbo charger..
3. The best indication of the heat in the turbo charger is an exhaust pyrometer which measures the temperature of the exhaust gasses. Best not to shut the engine down until those temperatures drop to 200C or less (they can be over 500C in many engines after hard work). The time required to cool the turbo can vary from zero to a couple of minutes, depending on what the engine was doing.

I fitted an exhaust pyrometer to the OKA, but since most modern vehicles do not have such a devise, it may be argued that they are probably not required and shutting down straight away does minimal damage.

Cheers,
Peter

Duh · Guru

Thanks for your feedback Peter, I always look forward to your replies, cripes you certainly are getting around, stay safe and happy travels in Europe... smile

Triple333 · Veteran Member

I asked my Toyota dealer last year and he reckoned it wasnt necessary but if pulling a load etc it wouldn't hurt to idle for a minute or so. But I don't think he really knew the answer!!!

QueenKombi · Senior Member

Perhaps more importantly is NOT to rev a turbo diesel engine when starting from cold or after a prolonged stop. The engine should be started at an idle so as to allow time for the turbo to be supplied with oil. A good rev immediately after starting will damage the turbo bearings.

Baz421 · Guru

QueenKombi wrote:
Perhaps more importantly is NOT to rev a turbo diesel engine when starting from cold or after a prolonged stop. The engine should be started at an idle so as to allow time for the turbo to be supplied with oil. A good rev immediately after starting will damage the turbo bearings.

Agree 100% QK,,,,, can I call you QK??? others do,,lol

Duh · Guru

Thanks QK, I wondered why in the handbook it said to start the engine without touching the accelerator, now I know why!! smile

Aus-Kiwi · Guru

Most modern turbo's are ball bearing and water cooled (CRS} centre rotating assemblies..
Diesel turbo's generally run cooler than petrol engines and spin much slower in most cases..
A ball bearing petrol turbo can easy spin over 150,000 rpm.. By the time you pull into driveway the turbo
is ok to turn off..

A turbo timer is for guys with Jap engines who want to spend money for no reason..

Some diesel engines will gum up rings .. We had a charter boat up in Bay of Islands and long hours trawling
for large game can gum up rings. In most cases the injector pumps warn't modified for marine use where torque is used
at higher rpm. Running rich at lower rpm.. The same could happen I guess if driven like Miss daisy on road ??
Modern diesels are higher revving, variable vane turbo and better fuel management so its not so much an issue..
Oils are SO much better these days also..

Duh · Guru

Thanks AK, I've found this a very interesting subject. I don't have my turbo anymore but still good info if I ever get one again. Seems a lot of European cars are turbo's these days (eg; VW's etc) smile

QueenKombi · Senior Member

Baz421 wrote:
QueenKombi wrote:
Perhaps more importantly is NOT to rev a turbo diesel engine when starting from cold or after a prolonged stop. The engine should be started at an idle so as to allow time for the turbo to be supplied with oil. A good rev immediately after starting will damage the turbo bearings.
Agree 100% QK,,,,, can I call you QK??? others do,,lol

Lost this post for awhile and no. I don't mind what I'm called. I get called lots of things in my position as a psych nurse. QK is fine and thanks for asking biggrin

QueenKombi · Senior Member

As far as turbo cooling down goes, I was told that unless I've been working the engine hard, I can switch it off straight away, however as my driveway is quite long, I usually let it idle all the way from the front in 2nd gear changing back to 1st near the house, so it effectively idles for over a minute anyway.

The other thing is that so far it hasn't worked hard at all. I never take the taco over 2,500rpm if I can help it. When I bought the Rodeo back in September, it didn't have a tow bar. I was disappointed until a friend who works in the car industry said that............... "at least you know it hasn't had the guts pulled out of it!"

New H/Reece H/duty tow bar $680 fitted. Bought a s/hand one for $220 and said friend helped me fit it last week-end. Only need a trip to the auto-electrician to have it wired now. The plug is there and the Rodeo has a plug ready to connect to the tow bar, but unfortunately the tow bar I bought is off a slightly later model and the plugs don't match up. The auto sparkie will probably cost me the difference between a new bar and the second hand one!!