synthetic oil question...

[secoleman57]

I went to syn3 mostly due to having one lubricant in all cases. A secondary consideration was possible decrease in change frequency (yet to be determined).

Most oil analysis companies such as Blackstone will tell you they run regular oil in their engines.

Take it for what you think it's worth, but these guys do see the effects of what is out there.

[lightguy]

Rule of thumb used to be NON detergent oil for break in period in aviation.
Dont even know if they make it anymore.

I'm switching to Synthetic after break in.
Harley in their manual recomends Diesel grade snynthetic oils.
Unless the Harley oil is reasonable I'm going with Shell Rotella T 5W-40.
Harley recommends 20W-XX weight.
I have no idea why.

[Rohan]

Originally Posted by lightguy

Rule of thumb used to be NON detergent oil for break in period in aviation.
Dont even know if they make it anymore.

I'm switching to Synthetic after break in.
Harley in their manual recomends Diesel grade snynthetic oils.
Unless the Harley oil is reasonable I'm going with Shell Rotella T 5W-40.
Harley recommends 20W-XX weight.
I have no idea why.

They recommend 20W because they built the motors and they know what oil they need. I would be scared to run 5W down here in the south. After it heats up and thins out I would think my motor would start having wear issues and overheating problems. It won't be too light for start up, but generally the larger the spread from the low and the high numbers there is the better chance for the viscosity to shear back to a lower grade over all.


-Rohan

[2010hdultra]

Well now for my 2pennies worth. The cvo machines come from moco with syn3 and i had a 2010ultra that started syn3 at 1k and never had any issues. 25k later still only less then 1/2 quart low at 5k change. Gonna do same with my 13 as soon as weather permits me to get to 1k.

[redman24]

Switched to Mobile1 20-50 Full Synthetic for VTwins in all 3 holes. Runs like butter. Shifting is a little louder, but still smooth.

[chasarms]

It won't hurt anything.

[tibadoe]

I switched to syn @ my first service (1000). No problems.

[lightguy]

Originally Posted by redman24

Switched to Mobile1 20-50 Full Synthetic for VTwins in all 3 holes. Runs like butter. Shifting is a little louder, but still smooth.

The engine and the gear box use the same oil supply ?!?!
Or just the same weight ?
The sumps are different right ?

[lightguy]

Originally Posted by Rohan

They recommend 20W because they built the motors and they know what oil they need. I would be scared to run 5W down here in the south. After it heats up and thins out I would think my motor would start having wear issues and overheating problems. It won't be too light for start up, but generally the larger the spread from the low and the high numbers there is the better chance for the viscosity to shear back to a lower grade over all.


-Rohan

The majority of wear comes at start up when the bearings are "dry" and there is no oil pressure or more importantly; flow. This is why low weight oils are best for most engines; its all about flow. I use 0-40 in my twin turbo Audi and everything else I can. If Harleys tolerances are real sloppy perhaps a 5-XX or 10-XX weight. As the engine build heat the viscosity thickens thus the high end of the stated weight. Multi vis oils automatically adjust.
If you want to get picky even 0 weight is too thick on start up for most every internal combustion engine made today.
Sounds crazy but thats the way it is.
If Harleys had hydraulic lifters there might be a reason for thick oil if they were engineered for it. AFAIK they use solid/roller lifters (?)

[Dave63]

Originally Posted by lightguy

The majority of wear comes at start up when the bearings are "dry" and there is no oil pressure or more importantly; flow. This is why low weight oils are best for most engines; its all about flow. I use 0-40 in my twin turbo Audi and everything else I can. If Harleys tolerances are real sloppy perhaps a 5-XX or 10-XX weight. As the engine build heat the viscosity thickens thus the high end of the stated weight. Multi vis oils automatically adjust.
If you want to get picky even 0 weight is too thick on start up for most every internal combustion engine made today.
Sounds crazy but thats the way it is.
If Harleys had hydraulic lifters there might be a reason for thick oil if they were engineered for it. AFAIK they use solid/roller lifters (?)

Yes.....this would be true, if Harley used Babbitt bearings.

They don't.

They're roller bearings and there's one bushing in each rocker arm and wrist pin. Oil PRESENCE is all that's required and it's there, even on start up. The oil psi you see is to feed the tappets, rockers and piston sprayers. Most of it is low to medium psi.

Harley has had hydraulic tappets, and has since the 40's....

You can't compare your Turbo Audi to a Harley. Different engine, different oiling needs and most importantly, different design, PERIOD.

Harley recommends no less than 20w50 in their engines, for normal use. The only time you'll see anything less, is in severe cold climates. At that, a 20w50 synthetic will work even better due to its resistence to cold-thickening.

Originally Posted by lightguy

The engine and the gear box use the same oil supply ?!?!
Or just the same weight ?
The sumps are different right ?

With all due respect, you're giving people advice on what to use on their motorcycles, yet you have no clue as to the design, fluid needs or oiling requirements of the vehicles you're talking about??

Engine: isolated oil/sump. Not shared with trans, like Asian bikes.

Trans/primary: Big Twin-isolated, Sportster-same fluid shared.

Originally Posted by lightguy

Harley in their manual recomends Diesel grade snynthetic oils.
Unless the Harley oil is reasonable I'm going with Shell Rotella T 5W-40.
Harley recommends 20W-XX weight.
I have no idea why.

No.....Harley does not RECCOMEND diesel rated oils. It states that in the absence of the recommended oil, (If unavailable) diesel grade oil can be used. It's not listed at all as their first choice, or their primary recommendation for their engines.

Why a 20w50 oil weight?

They recommend it because it's a roller bearing engine that's AIR COOLED. This isn't a babbitt bearing'd, water cooled bike where oil pressure is required, and the temps are much lower. Oil presence and cling rating is required. The engine will see higher temps in cetain areas than a water-cooled bike ever will.

I've read quite a few threads regarding using diesel grade 15w40 in Harleys with good success, including oil testing afterwards, via Blackstone Labs. I'm not going to recommend to anyone to use a 5w40, with the protection being less than HD requires.

The main reasons I'd not recommend 5w40, is due to the higher amount of polymers necessary to achieve that rating and the reduced cling ratings the oil has, especially when hot. The polymers are heat sensitive, and decrease/damage with high heat. Once reduced by heat, they don't "restore" on cooling. Your 5W40 could be reduced to 2w20 in one good, hot traffic ordeal.

It's an air cooled engine. Not a Ducati.

If you want to run it on your own, that's fine. The cost to repair or to relace internal parts will far exceed the cost of the proper oil you should have used.

Why people spend $20K on a motorcycle, then try to save money on the engine's life blood, is beyond me. Wanna save yourself cash? Just run Mobile-1 15w50.

Originally Posted by lightguy

As the engine build heat the viscosity thickens thus the high end of the stated weight.

Where are you getting your information from?

Multi viscosity oil does not "thicken" as it gets warm. It thins. The first number indicates the oil's viscosity cold. The second number indicated the oil's viscosity, when heated, indicating that it is no thinner than that oil rating (when hot), if it were a straight weight.

20w50- 20wt viscosity cold. At full temps, it is the same protection as a 50wt oil is, hot.

Due to the polymer's breakdown and oil changes that can occur with extreme temps, this is why HD recommends striaght 50wt in extreme temps. No polymer issue and better protection.

MULTI-VISCOSITY OILS
"Multi viscosity oils have polymers added to a light base (5W, 10W, 20W), which prevent the oil from thinning as much as it warms up. At cold temperatures the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.

Per Blackstone Labs:


Which Viscosity to Use?

Engine owners often stray from manufacturers' recommendations regarding viscosity of oils. The engine builders dyno-test their engines using a specific viscosity oil, so when you use the viscosity they recommend, you are working with a known result. Going to another viscosity is an experiment, but it's usually a harmless one.

For the sake of efficiency you want to run the lightest grade oil in your engine possible, within limits. We are seeing that trend for newer engines, for which the recommended grade is getting progressively lighter. The common 10W/30 has become a 5W/30, and some manufacturers even recommend 5W/20 oil.

On the other hand, we can't see (in oil analysis) where it hurts anything to run heavier 10W/30s or even 10W/40s in modern automotive engines. The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase. The trick is to find the right viscosity for your particular engine, which is why we suggest following the manufacturer's recommendation.

With Roller engines, THIS is what's important. It's not the same as a car's babbitt bearing'd engine.