Cooling down

[Zebedee]

I was prompted to think at the weekend (!).

Whilst queuing in the scrum to get into the camping at the BMF, the temperature gauge was creeping slowly but steadily up (no surprises there).

So, as a reflex action from my days when I was driving a truck, I left the engine running for a few minutes after I’d parked up (on the centre stand obviously).

The thinking being that with a hot turbo on the truck engine, the last thing you wanted was the oil boiling out of the bearings.

However, after I’d switched off the thought struck me that on the bike there shouldn’t bee any need to run the engine, as there shouldn’t be any areas of extreme heat.

Has anybody else got any thoughts on the subject?

Cheers

John

 

[richie]

Why leave it running, there is no fan so it will just get hotter. The riders manual suggests that when you start the motor just ride off and dont leave it to warm up first.

Not the same problem but interesting never the less

 

[Rabbitson]

I thought the whole point of leaving turbo engines running after a run was so that the turbo continues to be cooled normally for a period after a stop, if this doesn't occur, the turbocharger can become 'cooked' unless I'm mistaken

Don't see why you would want to leave a normally aspirated aircooled GS running though, especially if its already been sitting around getting hot for a while.

 

[Zebedee]

My initial reasoning for leaving the engine running was that the oil pump is still working, and therefore the oil would be 'cooled' as it passed through the radiator (oil cooler) before circulating round the hot parts.

However, as I said, leaving the engine running was a reflex action.

The reason I was given for leaving turbo'd engins running was that the if the oil stops flowing through the bearings, the oil will break down because of the high temperatures involved. Therefore, you keep the oil flowing until the temperature of the turbo has dropped.

 

[(RIP) Jamie]

Nah

Not an issue on the GS.

Engine design dates back prior to Turbo's anyway. It's virtually antiquated.

Believe it or not, I have sat in traffic (it happens) on the A6 in Hazel Grove, couldn't go anywhere. Anyways, it was the only time I had 6 bars up on the temp. gauge - hot day as well.

I think the only non-niggle with the boxer is the cooling. Some winter days on a bit of a ride it'll sit at four bars even.

You don't need to warm it up before going, nor run it down when stopping.

Anybody know of a boxer overheating and popping? I don't. be interesting if anyone did.

Jamie

 

[Banjaxed]

Zeb

The oil may be circulating, but if there's no airflow over the oil cooler the heat won't go anywhere and you'll be pumping additional heat into the system from ongoing combustion.

If you check out the spec of the police R1150RT-P, you'll notice that it has electric fans to draw air through the oil coolers. This is so the cops can leave the bike idling and stationary without the whole thing overheating. Like outside doughnut shops for instance...

Me? I'd turn it off as soon as I'd finished riding.

 

[Greg Masters]

I think that Paul's absolutely right!

Even at tickover, without an airstream passing over the bike, there's more heat being generated than is being dissipated by convection or radiation - else why would my bike have heated to 7 bars when Fanum stopped outside Strzemieszyce, Poland for a quick pee, which turned into a 15 stop whilst Mark Dilloway and I sat with our engines running?

It also reinforces the importance of using fully synthetic oil in any engine with runs any component at high temperatures (ie air or oil cooled engines and turbos) as fully synth maintains its lubricating properties at higher temps than does semi synth or mineral oil.

Greg

 

[brassmonkey001]

No air cooled engine is going to get any cooler when running and stationary unless there is something moving cool air over it at sufficient volumes to dissapate the heat being generated.

As for turbo engines it is important to let them idle before switching off to allow the turbo to slow down. Once you switch off the engine no oil is getting pumped to the turbo bearings, so if the turbo is hot and spinning at however many thousands of rpm and it is suddenly denied any lubrication or cooling from the oil then it is going to go 'PINK' (as in the sound not the colour). This is not a very alarming or exciting sound, at least until you see the bill that is.

 

[MikeP]

When we used to run R80RT's (them were the days!) and had to leave them running at accident scenes etc because of the emergency lighting, the front pipes would sometimes glow cherry red and you could see the pulses of the exhaust. We never had temperature gauges so never worried about it!!! My last one before we swapped to K's was a D reg and went to auction with 87K on the clock. It's still being run locally by the bloke who bought it and the engine hasn't been touched since then according to him.

 

[finglonga]

I read in a thread on ADVrider (I think) that someone had put an electric fan on the back of the oil cooler but it was 'pushing' air out the front of the cooler. Thus when you are on the move the fan doesn't have enough power to stop the forced air cooling the oil. But as soon as you stop in traffic and the like the fan will do the business of cooling the oil.

Sounded a good idea to me.

Or you could put a fan on sucking the air through the cooler in the conventional way and put a switch in line.

 

[Zebedee]

Cheers Guys,

As I suspected, I was wasting my time completely (so no change there ), but no harm done.

However, I do question the wisdom of stopping the engine when the bike is stationary in traffic for two reasons.

Firstly, I don’t like the idea of some numptie running into the back of me because he has assumed that I’m going to move off, and the bike has chosen THAT moment not to start on the first prod of the button. Secondly, because I don’t like the idea of running the starter motor (and therefore the associated relays) just for the sake of it.

That said, from now on when the bike stops, the engine stops