Oil Confusion, simplified...... I hope.

[blazer71]

Picture pointing out the tell tale machine markings

 

[Trashy]

Amsoil Dominator for this guy.... can't say i have seen any rust on teardowns.

 

[Ron]

Ditto Super Dave.....I have machined a ton of stuff on a lathe and that clearly looks like the end of a lathe cut pass as described by Super Dave. The end of the shiny machine section is cut in on the face by which looks like about .020" and the less dull metal is raised up revealing the original section length of the crank before the lathe cut ended. Shiny stop / dull start for those who might be lost.

The inside diameter where the bolt goes through into the crank has been machined too....you cannot obtain an inside diameter like that with out center punching it. The difference in color is probably a sequencing thing where it was machined to shape and then exposed to a hardening sequence and then they cut the taper for the primary afterwards.

Not an insert, not a sleeve, not two different types of metal.....trust a machinist on this one!

I am in on the $10.00 bucks too.

Here I am arguing with 2 experts now but am open minded enough to consider that I could be wrong. Your theory makes sense except for two things.
First the inside of the stub has not been turned, it has a raw metal look to it. Where it was cut on the outside it has "the shiny look" from a lathe. The outer edge and also the inside bevel appear to have been turned on a lathe just like the rest of the stub but reflecting 3 distinct colors. Shiny silver outer stub & lip, shiny grey edges of the insert & dull textured darker grey inside the insert.
Second the inner mark you described as a tooling mark is deep, it's not a surface mark. The tip of my scribe drops inside & the edges are slightly rounded not sharp as you would expect. There is no reason to cut a groove inside the shaft, wouldn't that create a fracture point?

Sorry to hijack your thread Dan! Looking forward to your opinion when you get the crank.

 

[Franz]

As long as the internal groove has a fillet in coners and is shallow, not a weak spot or fracture point. I agree with super dave, it was heat treated and then machined. Thats why there is different colors in the metal. They also wouldn't want to through-harden a shaft in this area because it would be brittle. There are cutting inserts on the market that cut heat treated metal easily these days. So this is case hardened. As to the questionable internal geometry it could be they had to clear away some material twards the end of the shaft to give clearance for other machining operations and the related tooling such as threading tools ect. just a machinist's guess.

 

[JET FUEL]

Maybe I can answer this question correctly,

Synthetics do not attract moisture as far as I am aware, but they do not do as good of a job protecting steel (your crank and bearings) from corrosion as good as petroleum based oils do.
Especially when you get into the oils that are billed as "Race Oils" becuase they leave out a calcium based corrosion inhibitor.

if you read the label on racing oils, they clearly state they ae for racing engines that get disassembled and inspected often.

it does not take long for steel to rust, sitting overnight is enough to get a slight rusting, and every time the engine is started that rust gets scuffed off , repeat this often and all those little tiny amounts add up to a huge amount of missing material in little time.
Many people think it is just from seasonal storage, I say it is from the simple fact of parking your sled overnight and the amounts adding up quickly.

I may be way off base here, does anyone agree or disagree?

I've had two cranks with rusted up bearings on them both with synthetic run through them, one thing in common though was both sat more than they were run, and one was a race sled (so you could have something there) the other was a little ol stock 600.Both polaris small block motors. the race motor was the pto and the 6 was the mag.

I've heard that ams-oil had to add stuff to keep this from happening with their 2 stroke oils.

I'm really not bashing any oil here I've run just about everything and am loyal to none. The only I've noticed is the smell(and amount of smoke) and how dirty or clean the power valves are.
I haven't noticed performance gain by going from one to the other.

 

[guidoxpress]

More great info!!!

 

[wanaber]

There is the issues of smell.

I have ran some oil that was 8 bucks a gallon cheaper than Ams and stuck so bad that I switched it use to starting bond fires.

I always thought the real world difference on oil was synthic's just allow you to not have to clean your power valves as often as with petroleum based oils.

 

[sledcaddie]

oil in cold temps

A friend and I were sledding at Snowy Range one time, and it was -14 degrees this one morning. His sled used non-synthetic oil, mine used synthetic. As we were fueling up and adding oil, his oil looked like molasses--thick and moving really slow. My oil poured smooth and easy, just like any other temperature. Translate this to the oil trying to flow through your engine, and you get the picture.
After starting your truck on a cold moring, how many of you have heard that one lifter tapping away for about 30 seconds until the oil finally reaches it? Thats bare metal-to-metal wearing! That's why Dan suggested synthetic for cold temps. I just run synthetic all the time, cuz I don't want the hassle of switching. I also run synthetic in my cars, mowers, boat, atv. The cost balances out because I only change the oil every 6000 miles instead of the usual 3000. I've been doing this for over 10 years, with no problems. Good thread.

 

[indydan]

Wow!!!!!!!

I have been away from this thread for to long.

I have to do some reading !!!!!!!!

my quick skim read was interesting!!!

 

[indydan]

crank stub

Sorry to hijack your thread Dan! Looking forward to your opinion when you get the crank.

No-problem Ron.

I forgot all about this crank stub thing..........

I have a bunch of these here right now.

I will take a look at them on Monday morning and post then.

 

[SledsWest]

good info. I just bought a few quarts of castrol 2T and will be running that this season.

TTT

 

[volcano buster]

Thought I would get out the spoon and mix this one up again.

 

[indydan]

Ron

WOW!!!!! Sorry Ron I have not been surfing for a long time.

I would say you guys are correct, the stud just seems to be stepped at the end...........why I do not know.