ORIGINAL: sedbiker62

Skip, first let me say I admire your knowledge and more often than not agree with your posts.
However, I gotta take issue with your statement "Turns over in mine just like any other 20w- oil."
While the Havoline may in fact turn over in your bike at 29 degrees. I can assure you that it does not flow in any way like a synthetic does at the same temp. Your petroleum oil has a moderatley high level of paraffinic content. Parafin begins to solidify at room temperature. As the paraffins begin to solidify, they form a honey comb like structure that at the very least inhibits flow, in the worst case scenario, stops flow. Even with additives to inhibit the formation of the honey comb structures, unless your petroleum oil is brand new, those additives degrade very quickly once exposed to the heat of engine operation.

A very simple and convincing experiment that can be performed at home tells the tale.

Place a quart of your favorite petroleum oil and a quart of your favorite synthetic oil in the freezer for an hour. At the end of the hour, pour the oil into a container of your choice. Let me know which one you want in your crank case in cold weather.
This is not a humble opinion, this is simply a fact. With all due respect

Steve[sm=icon_rock.gif]

ORIGINAL: iclick


centistoke viscosity units measured at 100 degrees (212 F) and centipoise viscosity units

Steve, the lower value in the SAE rating is measured by timing how long a quantity of oil can flow out of a graduated cylinder at 0°C (centipose viscosity), and any oil rated at 20w should flow at a similar rate as any other like-rated oil. The upper rating (centistroke viscosity) is measured at 100°C. That said, I once tested RP 20w50, M1 15w50, and RP Nitro 50 by placing them in my freezer (-12°C) for several hours. Using an unscientific method--holding a cup in each hand, pouring, and observing--I came up with this order (speed to empty the cup): Nitro 50, RP 20w50, and M1 15w50. There is no SAE rating for the Nitro 50 since it is a racing oil (for nitro-methane-burning dragsters), but the second and third placers should've been reversed. The results were not dramatic, but conclusive. Perhaps it would've been reversed at 0°C, but I doubt it.

Frankly, flow rates at 0°C are irrelevant for my application, for it is a rare occurrence for me to crank up in air temps lower than 45°F (7°C). Any 20w50 oil should flow fine in the temperatures most of us ride in. More importantly, synthetics tend to stick to metal surfaces longer than fossil oil, making the cold-cranking ordeal much less stressful. As we know, most wear on an engine occurs when cold starting. I saw this first-hand when an ex-client of mine, who markets synthetic-oil additives to oil companies, did a test on two identical vehicles in a near-identical environment for 30k miles, changing the oil at 3k intervals. One was 10w30 fossil and the other 10w30 M1. They removed the intake manifold and oil pan in each vehicle for inspection. For the engine running fossil oil, there was already a sludge build-up, while with the M1 there was none. In about an hour I noticed that the engine with M1 still looked "wet," i.e. there was still a coating on the lifter valley and other metal surfaces, but the fossil engine looked dry. One of the engineers described the stickiness phenomenon I mentioned before. This translates into easier cold starts and much less wear being realized on engines running synthetic oil.

ORIGINAL: pococj

Steve, I ain't got an argument with anything you said. Except maybe the part that the dino 20w- doesn't turn over like any other 20w-. A 20w- is a 20w-, whether its dino or syn. Granted one might be at the high range of the scale and the other at the low range, but I'm talking about seat-of-the-pants starting, in my case. I've run both Mobil 1 15w-50, Castrol 20w-50 synthetic, Castrol 20w-50 GTX, and the Havoline 20w-50 dino. Seat-of-the-pants, I can tell no difference in their starting in cold weather. Is there a difference? For my purposes, no.

I started using the Havoline when my engine sprocket seal started leaking badly. Too expensive to pour synthetic oil in the tank and watch it stream out all over the side of the bike and on the ground. I chose Havoline because of some used oil analyses on BITOG done on an Evo motored HD. The wear was less using the Havoline than even when the dude used synthetics. Seemed like a good thing - less wear, less expensive, and I could let it run outon the ground 'til winter!

When I get the bike back together after fixing the seal, and doing a few other things to it I'm going to run a load of M1 15w-50, then run a load of Castrol SynTec 20w-50, and finally a load of the Havoline 20w-50, having a UOA done on each after 2500 - 3000 miles.

My bike has about 130,000 miles on it. It had between 25,000 and 40,000 on it when I got it. I have no idea what oil was in it before I got it, but most of the miles I've put on it have beenusing Mobil 1 15w-50. When I pulled the top end off to replace the base gaskets there was still about 80 - 90% of the crosshatching visible on the cylinder walls.

ORIGINAL: sedbiker62

OK Skip, hard to argue with a 130,000 mile Harvey-Johnson. Don't know much about BITOG or the experiments done on the evo bike.
I am certainly not saying dino oil is bad, if it were it wouldn't still be on the shelf. Compared to dino oil of just 20 years ago, the current stuff is stellar.
Skip, come to the dark side[sm=vader.gif]Use synthetics...

Steve[sm=icon_rock.gif]

ORIGINAL: sedbiker62

ORIGINAL: sedbiker62

Wow! Thanks for the mind numbing explanation of viscosity. Very good, but mind numbing.
I still contend that even 20w oil, one synthetic and one petro, will be noticably different in my simple experiment. I will confirm it tomorrow and let you know.
With regard to the 15w50 M1 vs the 20w50 RP, both being PAO (polyalphaolefin) synthetics, the difference between the 15w and 20w is imperceptable, therfore to determine which has a better cold flow property would likely take a more scientific approach. The Nitro 50 is likely a 0w oil.
Bottom line, synthetics posses a superior cold flow property than petroleum.

ORIGINAL: pococj

The better "cling-thing" iclick talks about in his post is of more value than whether one flows marginally better. The synthetic's ability to cling to the metal surfaces will result in way less wear.

ORIGINAL: pococj

My bike has about 130,000 miles on it. It had between 25,000 and 40,000 on it when I got it. I have no idea what oil was in it before I got it, but most of the miles I've put on it have beenusing Mobil 1 15w-50. When I pulled the top end off to replace the base gaskets there was still about 80 - 90% of the crosshatching visible on the cylinder walls.