Another point of view on oils, ect

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comnoz said:
There is no doubt that some of the oil is vaporized in the really hot spots like the ring lands and exhaust spring pockets. I doubt that this accounts for much loss -but that is where you normally see the heaviest buildups of burned oil.
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An example might be the gold to brown to black color beneath the crown of a piston.

So is the phenomena on oil loss due to extremely low viscosity (due to local heat) at the point of loss (excessive ring pumping etc.) or...... volatilizing at the extreme heat sites on the cylinder walls, ring lands, and exhaust valve guides. I seem to recall worntorn stating that with the lower consumption oil the engine ran cooler. My gut is telling me that in wornotorn's example, the loss is going out the tail pipe.
 
Dances with Shrapnel said:
So is the phenomena on oil loss due to extremely low viscosity (due to local heat) at the point of loss (excessive ring pumping etc.) or...... volatilizing at the extreme heat sites on the cylinder walls, ring lands, and exhaust valve guides.
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That is a good question. Likely both.

I have put several measured samples of oil in the oven at 450 degrees and noted that some of the oils smoked and lost a lot of volume pretty quickly. They also got thick and turned the metal cup brown like the underside of a piston.
Other oils just darkened a bit.
 
comnoz said:
I have put several measured samples of oil in the oven at 450 degrees and noted that some of the oils smoked and lost a lot of volume pretty quickly. They also got thick and turned the metal cup brown like the underside of a piston.
Other oils just darkened a bit.
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Any of them taste like Salmon? :D

comnoz said:
That is a good question. Likely both.
Dances with Shrapnel said:
So is the phenomena on oil loss due to extremely low viscosity (due to local heat) at the point of loss (excessive ring pumping etc.) or...... volatilizing at the extreme heat sites on the cylinder walls, ring lands, and exhaust valve guides.
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So the question is still out there. Why under hot conditions, would one oil be consumed at a greater rate than another oil - as described by worntorn.


Yes, my major assumption going into this here is that the oil goes through the guide(s) and/or pass the rings and out the exhaust and a minor portion is volatilized and goes out the breather, or, is the oil volatilizing?

Now I don't know. Maybe the darkened oil is an indication of partial combustion (oxidising) of the oil or something.

Where is Gerry Bristow (RIP) when we need him?
 
One on-line reference suggests that as main and rod journals wear, more oil will be slung off the crank resulting in excessive oiling of the cylinder walls., thus increasing oil consumption. Is it a stretch to think that with a very hot engine, oil viscosity will drop and flow through the bearings will increase, thus over oiling the cylinders. Maybe in the case of worntorn bumping from a 20w50 to a straight 50 made the difference in viscosity at high temperatures.

At least one reference stated that volatilization is a minor factor and generally limited to poorer quality oil.
 
Dances with Shrapnel said:
One on-line reference suggests that as main and rod journals wear, more oil will be slung off the crank resulting in excessive oiling of the cylinder walls., thus increasing oil consumption. Is it a stretch to think that with a very hot engine, oil viscosity will drop and flow through the bearings will increase, thus over oiling the cylinders. Maybe in the case of worntorn bumping from a 20w50 to a straight 50 made the difference in viscosity at high temperatures.

At least one reference stated that volatilization is a minor factor and generally limited to poorer quality oil.
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There is no question that more oil is being pumped past the rod bearings -and everything else. That is why the oil pressure goes down when the oil gets hot.

The worst reaction I ever got to heating oil in the oven was from an old paper can of Pennzoil 10-40 -probably 70's vintage. I tried several different brands of oil by putting 4 ounces of oil in an aluminum cup and placing it in a pre-heated oven at 450 degrees. This was about 15 years ago.

In 20 minutes the old Pennzoil was pure black, boiling and smoking heavily. It lost at least 1/3rd of the volume.

Doing the same test more recently with Mobil 1 v-twin only turned the oil a little darker with a small amount of smoke and very little loss of volume.

I will try the same thing with the Fuche's synthetic when it gets here. Jim
 
Jim I'll be very interested in your Silkolene / Fuchs review.
I used Silkolene for a while but stopped when I saw low oil pressure once on my BSA / Tri triple track bike. I feared a bottom end rebuild was required but tested a different oil first and bingo, oil pressure was as fine, and stayed fine. I've not used Silkolene since.
 
So if it smokes or boils it is pretty safe to say it is volatilizing - increased oil consumption.

Excessive heat reduces viscosity which increases flow to the cylinder walls which can also increase consumption.

Are these the main reasons why the high temp diesel oils seem to be favored in the Commando for hot running?
 
I to will be keen on your review Jim, as it maybe a good replacement for my race bike , I am using Joe Gibbs (Driven) HD 50 synthetic in the race bike at present
I am using FUCHS Silkolene Comp 4 10W40 in the roadbike, have been for a couple of years.
It is quite dark to start with.
(off topic I use FUCHS Titan Supergear semi synthetic 75W90 in the TTI 5 speed gearbox)
Regards Mike
 
Yes -diesel oil needs to be able to handle the high temps normally found in the ring lands of a diesel. Oil that carbonizes at high temps cause the rings to stick in the groove -in diesels and in Nortons.

Plus diesel oils do not have to have reduced amounts of ZDDP to keep from fouling the convertors.

I still think ZDDP is a good thing in a flat tappet motor -in moderation.

While ZDDP does not help at all with the common 4 ball scar test, the reason it is there is for protection during the first few seconds of operation -before the part is flooded with oil. It's value has been pretty well confirmed over many years, no matter what Mr. BB Chevy says.

For ZDDP to be active it needs to be burnished into the part during high temp operation. Then it will help prevent scarring on the next dry start. Jim


Dances with Shrapnel said:
So if it smokes or boils it is pretty safe to say it is volatilizing - increased oil consumption.

Excessive heat reduces viscosity which increases flow to the cylinder walls which can also increase consumption.

Are these the main reasons why the high temp diesel oils seem to be favored in the Commando for hot running?
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If your oil is boiling or vaporizing then maybe you need better oil - if you can find such a thing !!
The boiling point and flash point of most oils is listed in their data sheets...
(and maybe a bigger oil tank).

There is a famous (but now fairly old) story with respect to oils boiling.

One of the competitors in the IoM amateur TT had to choose his oil.
He put a little sample of each (same quantities) in dishes in his oven, and turned the heat up.
The first one to boil was the first one to not be considered. The last one to boil was the one he chose.
He won his TT race....
 
The impression I am getting from this thread is that the best oil to use in a Commando is a modern, fully synthetic multigrade diesel oil. Have I got that right?
 
Rohan said:
If your oil is boiling or vaporizing then maybe you need better oil - if you can find such a thing !!
The boiling point and flash point of most oils is listed in their data sheets...
(and maybe a bigger oil tank).

There is a famous (but now fairly old) story with respect to oils boiling.

One of the competitors in the IoM amateur TT had to choose his oil.
He put a little sample of each (same quantities) in dishes in his oven, and turned the heat up.
The first one to boil was the first one to not be considered. The last one to boil was the one he chose.
He won his TT race....
Click to expand...

You have to be a fast rider as well.
 
ed.lazda said:
The impression I am getting from this thread is that the best oil to use in a Commando is a modern, fully synthetic multigrade diesel oil. Have I got that right?
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Probably the best is a modern multigrade synthetic motorcycle oil -but sometimes diesel oils are easier to come by on the road. Jim
 
comnoz said:
Mobil 1 v-twin oil is a completely different animal. Jim
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But not available in Europe.

You can get Mobil 1 15w40 motorcycle specific!
 
SteveA said:
comnoz said:
Mobil 1 v-twin oil is a completely different animal. Jim
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But not available in Europe.

You can get Mobil 1 15w40 motorcycle specific!
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Well that's a surprise. Guess you must have fewer HDs plu - er motoring about on the roads over there.

I'm not sure how Mobil 1 motorcycle oil would compare to the v-twin oil. Likely considerably lighter in weight since most modern motorcycles are water cooled.

Since UK doesn't normally see too many 38 degree days it may work well anyway. Jim
 
An oil cooler seems to be a good idea in avoiding thermal breakdown, especially out here in the West where it's 100 F. and expected to get hotter over the next week. i know many are dead-set against them for fear of the oil not "coming up to temperature". Yes, yes with a regulator for when its cold out.
 
L.E.N. said:
An oil cooler seems to be a good idea in avoiding thermal breakdown, especially out here in the West where it's 100 F. and expected to get hotter over the next week. i know many are dead-set against them for fear of the oil not "coming up to temperature". Yes, yes with a regulator for when its cold out.
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I used an oil cooler with a thermostat for many years on my bike. It took pretty extreme conditions to get the oil hot enough to open the thermostat.

The oil does get very hot in a few places inside the motor but since there is only a small amount of oil being overheated at a time -it does not raise the temperature of the bulk of the oil very fast.
I do think an oil cooler is a good idea if you use the bike hard.

I removed the thermostat from my bike a couple years ago and plumbed the oil cooler into the overhead oil line.
I have two large oil coolers inside my fairing and comparing the temp of the inlet line to the outlet line, they drop the oil temperature a lot.

I like the difference it has made in my cylinder head temperature but I didn't see much change in the temp of the oil in the tank. The oil tank temp usually tops out somewhere between 230 and 260F under the hardest conditions -like climbing a pass.

I have seen it go considerably higher than that when stuck in stop and go traffic for a long time. But the only thing that would help that is a cooling fan. Jim
 
I just spent two hours digging through the linked blog. Thanks a lot Jim !?&%$#@

A few relevant points for we Norton owners jumped out:
- Don't buy oil based on the zinc content.
- Diesel oil doesn't mean better oil.
- Motorcycle oil isn't necessary better oil
- Synthetic oil isn't necessary better oil.
- Oil additives may help, but most don't.

I had a few "problems" with the article:
- The author's measure of oil quality is film strength. Probably the best real world measure. But not a readily available testing standard. And you won't find the data on the bottle of oil.
-Most of the oils tested do not have the viscosities needed in our old bikes.
-Some of the higher rated oils benefit from two additives: Prolong Engine Treatment, and Oil Extreme concentrate. I appreciate that the author states he has no commercial interest in any oil products, but the critical reader is left wondering why only these two products are mentioned. Because they worked? Compared to what other additives?

The article has me rethinking my recent decision to run diesel oil because of its high zinc content.

Stephen Hill
 
Stephen Hill said:
I just spent two hours digging through the linked blog. Thanks a lot Jim !?&%$#@

A few relevant points for we Norton owners jumped out:
- Don't buy oil based on the zinc content.
- Diesel oil doesn't mean better oil.
- Motorcycle oil isn't necessary better oil
- Synthetic oil isn't necessary better oil.
- Oil additives may help, but most don't.

I had a few "problems" with the article:
- The author's measure of oil quality is film strength. Probably the best real world measure. But not a readily available testing standard. And you won't find the data on the bottle of oil.
-Most of the oils tested do not have the viscosities needed in our old bikes.
-Some of the higher rated oils benefit from two additives: Prolong Engine Treatment, and Oil Extreme concentrate. I appreciate that the author states he has no commercial interest in any oil products, but the critical reader is left wondering why only these two products are mentioned. Because they worked? Compared to what other additives?

The article has me rethinking my recent decision to run diesel oil because of its high zinc content.

Stephen Hill
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Don't go completely away from looking at ZDDP content. Look for around 1000 to 1300 ppm.

The authors testing does seem to revolve around film strength, ZDDP does not affect film strength except when there is extremely high concentrations -which adversely affects film strength.

I suspect this is where he has gotten his dislike of ZDDP.
The addtional ZDDP in some of the additives were most likely what caused a reduction in film strength when added to a lube that already had lots of ZDDP. Jim
 
I see Valvoline now offers the VR1 racing oil in a full synthetic as well. The description states that it has a high ZDDP count just like the conventional VR1.
So far it's showing up as 5w50 only.

Glen
 
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