Oil temp findings

First ride this morning with my new MG Cycle thermometer dipstick in place. It’s an analogue gauge, so allow a few degrees either way, not that it matters. Here’s some basic data in degrees Celsius. I’ve put Fahrenheit in brackets for the imperial system folks. All measurements taken the same morning, with the first measurement after the bike was running for at least 30 minutes. The ambient temp fluctuations were due to me heading out in the morning, and going from sea level into nearby hills where it was cooler, then back down to sea level again. Weather was clear and dry.

17 degrees (63) ambient. Surburban riding. Oil 105 degrees (221F)
15 (59) ambient. Hilly area but slow 60kph (37mph). Oil 110 (230)
14 (57) ambient. Hilly area, mostly downhill. Light throttle. Low speed. Oil 100 (212)
20 (68) ambient. Highway, typically 100kph (60mph). Oil 102 (215)
22 (72) ambient. Suburbs. Stop/start a bit, 40-60kph (25-37mph). Oil 120 (248)

So, I was a little surprised that the oil was as hot as it measured. At no point did it drop below 100 degrees Celsius, so any condensation vapour should have burned off. The lowest temp was, not surprisingly, when ambient was at its coolest, riding through the hills at light throttle openings. The bit that surprised me was almost identical low oil temp was achieved at steady highway speed, even though ambient temp was 6 degrees warmer. Suppose the air-ram effect is at play here.

The other interesting observation was that the hottest temp was at low speeds in a suburban riding environment. When the bike is stationary at traffic lights etc, it picks up temp very quickly. With a much reduced air ram effect at low speeds, the oil had little problem getting to 120 degrees C, even though the day was quite mild. On a hot summer’s day you’ll push past 130 easily, probably more.

These ambient temps are pretty typical for much of the riding conditions I encounter, yet my bike still has the dreaded mayo symptoms. I’m starting to wonder whether the oil temp isn’t an issue at all, but the mayo is just a product of the cooler parts of the breather system which cause the condensation, and which will persist no matter how hot the oil is.

Also, this begs the question as to what the “ideal” oil temp is, but with the readings I saw today, I’d be less inclined to block the oil cooler off than I was beforehand.

(EDIT: my wording may have been a bit clumsy above. For context, there still appears to be an over-cooling effect, especially if you ride in colder climates. If you cruise down the highway in single digit temps, forget it......the oil will likely never hit 100, let alone more.)

I’ll keep taking notes and see if any other variations pop up.

Brent.

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Got mayo???

Out of curiosity, I suggest you put your thermometer into boiling water for a calibration test.
And I should also do the same for mine, as my temperatures are not as high as yours, despite similar ambient temperatures.

Good idea Dave. Will try that and report back. Must admit to being slightly surprised at the highish temp readings for what was a fairly mild morning.

Brent S wrote:

Good idea Dave. Will try that and report back.

I've just completed my test, using a laboratory type immersion thermometer and my MG Cyle "#300033070 dipstick thermometer (V11 Cali's, '15 GRiSO, & early sump spacers).

I was surprised (and impressed) how closely these two thermometers tracked each other, from 40°C right up to the boiling point of water 100°C.  The immersion thermometer reading fell slightly behind as the boiling point was reached, the dipstick thermometer was bang on.

Your turn, Brent.

Err, except I don’t have a reference “immersion” unit which I can use for comparison! All I can really do is boil some water and see if it reads bang on 100 degrees Celsius or not. Hardly very scientific, but my options are limited.

That will still work. It's the critical temperature where the water will boil off that's important, I reckon.

Made also a test ride with my gauge newly installed. Outside temperature was about 16ºC and Oil temperature was 100°C.

The end of my drive back home is in an urban area with traffic and traffic lights.

The deepstick brand is R&R.

It looks like the measure is in the same range than Brent S ones.

The Mayo effect may be just down to the brand of oil in use - I use to use Duckhams 20/50 on my old brit bikes and always got mayo, changed to Castrol and it went away.

Possibility?

Using Motul oil. Never used anything else in the Guzzi, so have no real basis for comparison to other oils.

BrianD wrote:

The Mayo effect may be just down to the brand of oil in use - I use to use Duckhams 20/50 on my old brit bikes and always got mayo, changed to Castrol and it went away.

Possibility?

More likely the Castrol was not as efficient as the Duckhams, causing the engine temperature to rise (I know I'm stirring up a hornets nest here).

For the GRiSO 1200SE the oil is specified as: IMPORTANT. USE HIGH QUALITY 10W-60 OIL

if you look at my mayo shot above, that occurred with a lot of short commuting in less than 10ºc ambient temps.
It happens quite quickly too...
Solution: ride it like you stole it, take the long way home, get it hot an keep it hot.
Haven't had the issue since.
-after I first found the mayo, I was lifting rocker covers every week for a while.

Some further (slightly rough) oil temp data from a ride this morning. About 22 degrees Celsius ambient and dry. Steady cruising at 60kph along a bayside road, with very little stop/start action. Modest throttle openings. Bang on 100 Celsius. Mix in a bit of traffic, some side roads etc and it picked up to 105 degrees very quickly. On the way home I was doing some suburban arterial roads (frequently stopped at traffic lights, giving it some berries on the green, then cruise at 80kph. Then into some suburban side streets, on and off the throttle.......peak of 110 Celsius. Ambient had crept up a degree to 23 by the end.

So, what is this telling me? Not entirely sure, but if the conventional wisdom is to keep your sump operating temps above 100 Celsius to theoretically stop mayo symptoms, then this is very easy to achieve in normal riding during temperate days. Blocking off the oil cooler would, IMO, be overkill in these conditions.

My feel is that as we drift into the cooler months, the situation will change. Open country roads + higher speeds + cold air = low oil temps. Already found on a previous ride that the oil refused to go past 100 degrees even at a steady 100kph, and that was with ambient temps in the low 20s.

Will collect a bit more data as the days get cooler.

93F (33C) ambient yesterday, after two different rides, oil temp was 120 degrees but it is breaking in.

What has surprised me is that when setting throttle bodies the 8V motor spikes right up to 125C on the 1st rev up to 5K rpm. The 1100 motor is a bit easier on the spike w/setting sync. I was also surprised that 1/2 the lectric fans don't even work at 125C like they are supposed to. Junk, utterly JUNK .

24 inch shop fan running in front of the bike fixes that.

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Received my MG Cycle adjustable oil cooler cover today. A small gripe, being that the product pic on the sellers website shows the item having a matt coating, whereas I open the box to find that mine has a gloss shiny black finish. Suppose that opinions may vary in terms of which looks best, but given that there are no other high gloss parts on the bike in the immediate vicinity of the cover, the matt finish may have blended in better. It probably really doesn’t matter much[You must be registered and logged in to see this image.]

Now fitted, I must admit that it looks considerably better than the stock item which had warped very ordinarily over its life. Yep, happy with this extra bit of bling.........