Synthetic vs conventional oil's effects on stator longevity

[rustybronco]

This post was brought about as a tangent to Permanent Magnet stators failing.

It appears to me, and from what I can gather others, the normal reasons for stators failing are wide and varying. Those reasons range from age related insulation breakdown, vibration caused insulation breakdown resulting in shorting to ground, over (under?) voltage regulation issues, insulation breakdown resulting in windings shorting to each other, use of R/R's which return more current to the stator (MosFET?), chassis wiring related issues etc. The list is long and varied.

Now to the main question.

Do you think that changing to a synthetic motor oil (true synthetic vs hydro cracked?), with its greater ability to transfer heat, will help the PM style stators live longer?

And, as a continuation to that line of thought, how do you feel about true synthetic's like Amsoil (Motul etc.) vs hydrocracked synthetics.

Your factual, actual or well reasoned thoughts on the subject please.

[tkent02]

The one GS 550 I rode for over 100,000 miles with no charging system problems, from 20,000 to 120,000 miles on the odometer, was run on synthetic oil exclusively. Amsoil at first and when other synthetics became available in the right grades used Mobil 1 and then some others, but always synthetic. Haven't had electrical troubles on any of the others though, they have used all kinds of different oil.

Would not have thought the type of oil would matter, but maybe it does.

[Gorminrider]

Am I wrong? but I think the stator is mostly in air....Seeing how the FlywheelMagnet spins so close to it, I can't see how oil would be as important as air as the major coolant. ...
Question:
Is there a pressure stream of oil to the stator?
If so, Which passage on the sidecover does it?
Finally, (given it exists) It follows that this "oil jet" intended to cool needs as much attention as any other component of the charging system where stators are "Burning up" for no good reason due to wire gauge.

I can't yet tell the difference except in $ as to oil.

[rustybronco]

Tom, for the first 20,000 miles, how old was the stator? Was it fairly new or had the bike sat for years? One would speculate both heat from use and (or) aging would have an effect on it's insulation.

It would reason the less you cook it, the longer it should live.

[JEEPRUSTY]

A combo oil and electrical thread awesome!

[rustybronco]

Am I wrong? but I think the stator is mostly in air....Seeing how the FlywheelMagnet spins so close to it, I can't see how oil would be as important as air as the major coolant. ...
Question:
Is there a pressure stream of oil to the stator?
If so, Which passage on the sidecover does it?
Finally, (given it exists) It follows that this "oil jet" intended to cool needs as much attention as any other component of the charging system where stators are "Burning up" for no good reason due to wire gauge.

Gorminrider, yes the stator is mostly in air. But there is no circulation of air to help remove that heat. The way I see it is, the majority of the heat is conducted away from the stator by way of the aluminum cover.

Now the question becomes, does the oil's contact with cover help remove the heat from the stator, or does it hinder it? (the oils effect on the stator heat not withstanding)

The oil which contacts the stator is via splash (slosh) only

[tkent02]

Tom, for the first 20,000 miles, how old was the stator? Was it fairly new or had the bike sat for years? One would speculate both heat from use and (or) aging would have an effect on it's insulation.

It would reason the less you cook it, the longer it should live.

I bought the 1977 550 in 1978 with just under 20,000 miles, maybe closer to 19,000. I believe it was the original stator, not sure.

Rode it until maybe 1983 or '84, rebuilt the leaky 120,000 mile engine and sold it to my brother, he rode it a while and sold it on. So no, not very old in years.

Never used any extra electrical equipment, no big lights or anything, always wound it out everywhere.

[RichDesmond]

Like all oil-related questions concerning real-world effects, the correct answer is, "we don't know".

Where have you read that synthetics have a greater specific heat than convention oils? I've never heard that before.

[rustybronco]

Seeing how the FlywheelMagnet spins so close to it, <snip>

Which brings up and additional question I was thinking about that is only slightly related. On the BMW F800GS series, they redesigned the flywheel and incorporated larger cooling holes.

http://www.hildstrom.com/projects/buellstator/

[tkent02]

Where have you read that synthetics have a greater specific heat than convention oils? I've never heard that before.

I haven't heard that either, but I know synthetics can be hotter longer without building up that black sludge that clogs up engines. Maybe not building that sludge up is the difference.

[Steve]

Where have you read that synthetics have a greater specific heat than convention oils? I've never heard that before.

I was wondering about that, too.

I have always known that synthetics could handle heat better without breaking down, but have never heard that they transferred heat any better.

.

[rustybronco]

Like all oil-related questions concerning real-world effects, the correct answer is, "we don't know".

No we don't know. But we have thermal imaging devices in order to test the theory with.

Where have you read that synthetics have a greater specific heat than convention oils? I've never heard that before.

It was on some Amsoil site.

In my line of reasoning, the more consistent the oil molecule's size the more contact area and the better transfer of heat.

[OldVet66]

I used to use the Rotella synthetic for 10,000 mi. until I developed a head leak. Switched back to the Rotella dino, leak stopped and I noticed the motor ran a little smoother with the thicker oil with larger molecules (reason the leak stopped). I don't think the stator cares one way or the other. I think my CompuFire series R/R more than compensates for oil type and heat.

[rustybronco]

Reading material...

This link is in regards to transformer oils but it should still be relevant to the discussion .

http://lubricants.petro-canada.ca/pdf/LUB2403E-ImprovedHeatTransfer.pdf

Thermal Conductivity is essentially “the measure of the ability of a material to conduct heat”[4] or to put it simply, it is the rate of heat transfer. The higher the thermal conductivity, the faster the transformer fluid will transfer the heat from the hot coils to the outside air.

Naphthenic oils and iso-paraffin fluids are manufactured using distinctly different processes. Naphthenic oils are typically manufactured using solvent refining processes coupled with mild hydrotreating / hydrofinishing or hydrotreating alone. This leaves residual compounds in the oil, such as sulphur, nitrogen and aromatics [2].

Iso-paraffin fluids on the other hand, are highly refined using a newer technology, involving severe hydrocracking / hydroisomerization processes. This eliminates almost all of the contaminants from the fluid and leaves it virtually sulphur-free.

http://www.machinerylubrication.com/Read/472/base-oil-industry

Solvent Refining (Paraffinic Base Oils)

By approximately 1930, solvent processing emerged as a viable technology for improving base oil performance using a fairly safe, recyclable solvent. Most base oil producers in the world still use this process today.

Approximately half of the base oil in North America is currently manufactured using this route. Solvent refined base oils are commonly called Group I base oils which are characterized as those having less than 90 percent saturates (>10 percent aromatics) and more than 300 ppm sulfur.

[RichDesmond]

No we don't know. But we have thermal imaging devices in order to test the theory with.

Even if you showed that it ran a degree or two cooler, (which I doubt it would) you still wouldn't know. The only way to know if it has a real, real-world effect is to run a few dozen motors, split between conventional and synthetic, on computer controlled dynos for a thousand hours or so and see if the wear rates and failure rates for the synthetic oil motors are lower. Obviously the cost to do that is prohibitive, so there isn't any real data, so people just make up theories, or cherry pick lab data, and draw unsupported conclusions.

It was on some Amsoil site.

Not exactly an independent source.

In my line of reasoning, the more consistent the oil molecule's size the more contact area and the better transfer of heat.

That makes no sense. There's no physical reason that size consistency would have any effect on contact area or heat transfer.

Just in general, I've never seen any direct, measurable advantage for synthetics. Switching to synthetic doesn't make an engine run cooler, and it doesn't make more HP on a dyno.