Does idling cause a warm engine to cool down or get hotter? By mike932 (Read 1,294 times)

[mike932]

Let's say I go for a long ride on my air-cooled scooter.  If I then park it but leave the engine running, will the engine cool down or get even hotter?

[jerryscript]

It all depends upon how hot it is when you get back from the ride. If your long ride was at WOT, then it would probably cool down a bit while idling. If it was a leisurely ride with RPMs staying in the 4-5k range, it might get stay the same or even get hotter. A few minutes is no big deal, you can spend that much time at a stop light. Longer than that, there is no reason to leave it idling other than starter issues.

Would be interesting to see some real world results on this. I don't have an IR thermometer, might have to pick one up, I've been considering a water cooled kit for my 150 to help during Vegas's hot summers.

[Alleyoop]

Idling for to long the motor is going to get hotter, no difference than with a car caught in traffic.
Alleyoop

[jct842]

It would be a great project for some one to measure a few gy6's to see what happens. They are a fan cooled engine. At speed the fan is going to run faster granted but the engine is going to be working as hard as it can. There is little evidence that at speed extra air can not do much as they have the cooling shroud and the only other help to cool would be the bottom of the engine.

I know a briggs will idle all day long no problem and run fairly cool but put it to work and it is going to get a lot warmer. Its a well know fact that as a fan speed goes up it looses some efficiency.

I would guess a gy6 to run coolest at either idle or possibly 10 15 mph.

[rks]

As stated above, it depends on how warm it got during your ride. Install an oil temp gauge, then you will know. I always let mine idle down for a few minutes after longer rides, or climbing the hills to get home from town. I posted some numbers here last December......of course, your mileage may vary.. This is what I wrote then......

VDO Oil Temperature, Electric, 120*f to 300*f + VDO sender installed in left side oil drain hole.

Operating temps vary with ambient air temps, and engine load. I can start scoot, warm it up for 4 to5 minutes, ride 6.8 miles for coffee, and the oil will only get to 180*. Might add that the first 3 of those miles, result in an elevation drop of 1,000 feet. Longer trips of say 12 to 20 miles result with oil temps leveling off at 220* or 230*. Get on a good climb and 240* to 250* is not uncommon. Have seen 260* on occasion, when pulling in the driveway, but it has to be a really hot day. If parked on center stand, and allowed to idle 5 minutes, you can watch the temp drop 15 to 20*..

These numbers are what I've experienced......I don't ride at WOT, if you do, I would expect higher temps. If you ride in 95 or 100 degree weather. I would expect higher temps.

In late fall, with cooler weather, I had days that the oil didn't reach 200*.

Read more: scooterdoc.proboards.com/thread/11223/oil-pressure-temp?page=1#ixzz3RWOXNcEh


Read more: scooterdoc.proboards.com/thread/11223/oil-pressure-temp?page=1#ixzz3RWMw3LT0

[mike932]

rks, I ride WOT almost all the time. Is that bad for my engine?

[cyborg]

LOL we must be related Mike

[richardv]

An internal combustion engine is designed to produce heat and convert it into rotational force. So there for it should not cool down. An efficient heat transferal system, air or liquid, may bring temperature into acceptable range weather idling or WOT. From my experiences an air/liquid cooled engine will increase in temperature briefly upon stopping but only for a brief time. Water cooled take a little longer.

[DrRocco]

There's no way to say for sure. There are too many variables in the mix. Riding RPMs, Ambient Temp., Ambient Humidity, Airflow across the cooling fins... The answer to your question changes dependently on the balance of many conditions. That's my $0.02 at least

[rks]

As I stated a bit earlier.....install an oil temp gauge, and see for yourself

[img src="i1271.photobucket.com/albums/jj622/rks3526/Unknown.jpeg" src="" alt=" "]

[jerryscript]

If you just want to check temps when stopped, an oil temperature dipstick is the way to go:

link

Take a stick and measure how far you can go down the tube first so you can find one with the appropriate length. You don't want the probe to touch the inside of the engine case, but you want to be as far into the oil as possible, the oil in the dipstick tube may not circulate enough to get accurate readings. Here's a thread where a guy made one himself and spot welded an extension on to a candy thermometer that was too short (I would have spent another $10 to get a properly sized probe myself).
xs650temp.proboards.com/thread/16693/temp-dipstick-homemade-simple-cheap

[richardv]

From my experience tuning air cool engines is that if there's no fan to keep the air moving you will need one. If you are in a mostly enclosed space with your scooter, even though it has a fan on the motor, you will want a fan to move the air in the space. If the space is well ventilated there no problem.
The real hot spot is the exhaust valve area and there are sensors that can be attached to that area.

[glavey]

I put an oil temp. sensor in my scooter before I installed an oil cooler so I had a baseline to compare readings with. I can confirm, at least in my case with my 139QMB w/ 72cc BBK, that idling causes oil temperature to increase more than if the scooter is being run at around 50% throttle.