Motor Oil 101

[timsatx]

I finally found this series of articles. I found it once before forgot the link. I found it very interesting.

http://www.bobistheoilguy.com/motor-oil-101/

[Boomer]

A friend once told me that the most important thing about engine oil is to use some. 
Some oils can go longer between oil changes (Synth & semi-Synth), some have friction modifiers (not to be used with wet clutches) but otherwise use the correct viscosity and change at the recommended intervals.
Personally on my older bikes I change every 5k miles, mainly because it's easier to remember.
When the odometer goes past x5,000 or x0,000 it's oil change time.
I also use flushing oil when it's an x0,000 oil change.
So far 170k miles and still going.

[Gitbox]

Flushing oil?


Please explain and pardon my ignorance.

[sherob]

I think he's talking about flushing his engine.

[Rhino]

Interesting read. That guy must be a VERY successful surgeon and biochemist. Ferrari, Lamborghini, Maybach... Dr. Jay Leno.

My first car in 1974 was a 1966 Olds 442. Someone had done some work on it as the heads were not original. It never had good oil pressure. I took it to college in Tucson, AZ and in the heat oil pressure got worse. To get the oil pressure up I put thicker oil and sometimes STP. Eventually the engine seized. When I took the intake manifold off the cam was in 3 pieces. Now I know why. Would have been better with thinner oil and low oil pressure. Of course would have been better to figure out why the pressure was low and fix it but I was living on Raman at the time and had zero money.

Also now confirms what I always thought, Rotella 5-40 is not too thin for my 3 ATV's and 2 bikes.

[Gitbox]

Right - I'm not familiar with flushing an engine. How does one do that?

[sherob]

Right - I'm not familiar with flushing an engine. How does one do that?

Carefully... carefully... careful... l... y.   

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=470189 

[timsatx]

I sorta did it on my last oil change a couple of weeks ago. I added Seafoam to the oil and let it idle for about 20 minutes, then drained it. I might be more concerned about driving it but not just idling. In fact, I even put it into first and second gear to let it run for a minute and no problems.

http://seafoamsales.com/using-in-crankcase-oil/

[Leo]

I have never gotten too excited about any of the amazing type oils.  I guess they do not hurt anything.   I just use regular motor oil, of the weight the manual says.  I have never broken down when I had motor oil in the crankcase.  Every engine I ever saw without motor oil was ruined.  I have always gotten tired of motor vehicles before I wore them out.  I don't care how good it is running, by 200,000 miles I want a different vehicle.

[IraB]

I finally found this series of articles. I found it once before forgot the link. I found it very interesting.

http://www.bobistheoilguy.com/motor-oil-101/

A very interesting read that almost has me wanting to switch from dino Rotilla 15w40 to synth Rotilla 5w40.  I use my bike for a lot of very short trips and the thinner oil during cold run may be an improvement.
One thing I am not so sure about in the article is the poo, pooing of the benefit of thicker oils clinging to parts better during overnight shutdown and providing protection on startup.  While quick flow to bearing is very important there is a reason engine builders lube everything during assembly too.  I guess the art is in knowing where to split the difference.

[Summit670]

I've had the same thoughts regarding cams and such retaining a better oil film if using a higher viscosity oil.  I'm using the 5w40 and will continue unless someone come up with an answer.

I agree the 5w will be able to flow easier upon startup, and the parts would get 100% of oil quicker.  How many engine revolutions does it take to start lubing at an acceptable level?

If you use a 20w, there is probably a thicker film of oil to begin with.  How many engine revolutions does it take before lube starts flowing at an acceptable level and will the residual 20w film fall below what would have been left of 5w oil, and for how many revolutions?

[works4me]

The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
 
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.

[IraB]

The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
 
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.

While I do not totally disagree with you I also doubt anyone would want to crank up an engine that had zero lube on anything.     This is also the time an engine gets hammered with wear.
Oil does provide some very important lubrication on start up before proper flow (which I agree provides far more lubrication) is established.
The real question seems to be, what oil type/viscosity provides the best in both situations.

In a related story, A friend used to own "The Buggy Barn" and specialized in air cooled VW service and custom work.
He worked late into the night to build and install a custom 1776 cc engine using lots of a 50/50 mix of STP and Castrol 20w50 as assembly lube. He left the final plumbing and wiring for one of his employees to do in the morning.
The kids goes to work in the morning, gets everything all connected, fires it up and of course romps it out of the parking lot and down the street to "break it in."   
Engine starts running like crap so he heads back and after about 8 miles it seizes up.  He had not put ANY oil in the crankcase and of course it was trashed.
Without any thick oil film in that engine who thinks it would have driven anywhere near that far?

Built many VW motors and always used my friends homebrew assembly lube.

[VirginiaJim]

Good information.  Thanks for the link.

[Boomer]

Flushing oil? Please explain and pardon my ignorance.

Ignorance is FUTILE! 
Google is your friend.

[Steve in Sunny Fla]

The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
 
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.

 This^
  If any of you are familiar with Smokey Yunick, He did an experiment by building 2 identical smallblock chevy engines, except on had babbit shell bearings and the other had roller bearings. Of course there was alot of work to build the modular crank, etc, but he had high hopes that the roller motor would really produce great HP. When they dynoed the engines the produced the same HP. He scratched his head, then concluded that the regular bearings produced no excessive drag because the parts were being separated by the oil layer, and therefor there was no more friction than the roller motor had. He did conclude some power could be gained from lessening the oil pressure and the attending pumping losses, but didn't feel it offset the effort to build the roller crank assy.  Steve

[connie_rider]

I thought it was interesting, so I read his article until my eyes started to bleed.
Yes it is Interesting,,,,,  but more than I really need to know to ride my Connie.
I run the Rotella T (15/40) Dino Oil and change it regularly.    Works for me....

NOTE: Recently I tried the Rotella Synthetic.... It worked for me too.
           I think it may have have shifted a bit better.
              Cost MORE....

So, I went back to,,,, I run the Rotella T (15/40) Dino Oil and change it regularly.

Ride safe, Ted

PS: I live in Houston. Don't worry much about cold weather start ups...

[enim57]

As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.

I don't know how this measures oils "clingability" which is the ability of oil not to drop off a part.
This method is the same technique used to measure viscosity.

Regards, Russell

[IraB]

I don't know how this measures oils "clingability" which is the ability of oil not to drop off a part.
This method is the same technique used to measure viscosity.

Regards, Russell

Not sure dropping a cam in a bucket of oil proves that it only protects against corrosion.
Would you rather drop a nice cam in an empty bucket or one full of oil? 

[works4me]

Not sure dropping a cam in a bucket of oil proves that it only protects against corrosion.
Would you rather drop a nice cam in an empty bucket or one full of oil? 

At rest there is metal-to-metal contact.
That contact continues until oil pressure can hydraulically
separate the components.
Hence the premise: "highest wear at start-up". 

The thin film that "clings" is insufficient to protect
against this wear.