Technical Synthetic Oil verses conventional motor oil.

LOL have you ever tried to do calculas on an abacus?

Here is a problem that I have encountered with synthetic over dead disnsaurs. I had a guy roll in last summer with a late model bike that ran synthetic as opposed to common oil. I live about 40 miles past Pig Snarf these days and he got sent to me for his problem. This guy would not put oil in hos bike and he was a quart down. I ended up getting on the horn and find him the oil that he wanted and took a 3 hour round trip to get him a couple of quarts one to dump in his oil bag and one for his saddle bag.

Road trips can be a problem still unless you carry extra oil, this will change in the future and dead disosaurs will be the oil you cannot find. Such is life I guess.

 

Don't take this the wrong way, I'm not challenging you on this statement or trolling, this is a serious question. How can the same oil be both not too slippery to prevent ring seating, but more slippery to prevent cam wear? With over 20 years in the lubrication business, and certified to the highest levels in the biz, I don't get that. If synthetics have too much lubricity to prevent the rings from seating, wouldn't they be better at preventing metal to metal contact between the cam & lifters? Or, if "break-in" oils are better at preventing metal to metal contact and wear at the cam/lifter contact, wouldn't they also be too "slippery" for the rings/cylinder walls? Are their additives in the break-in oil that can tell the difference between the cam/lifter and the rings/cylinder. Something is not making sense to this old lubrication engineer.

 

Note they don't include any technical reasons for this advice, not any sources, nothing. I don't know, perhaps there is some validity to this advice, but it would be nice to know what it is. I'm sorry, too many years of training that causes me to question everything and be skeptical. IMO skepticism is the proper reaction to take when somebody makes a claim, the onus is on the one making a claim to be able to back it up, not on the one questioning it. When somebody doesn't provide some kind of backup it reeks of just repeating FUD (fear, uncertainty, and doubt). Personally, that advice means zero to me. If you think it merits attention, go with it.

 

From a mechanics/machinists point of view ring seating depends on your hone and cross hatch. Not the oil used.
I am not an oil man by any means, and cannot discuss the differences between breakin oil and common oil with any level of intellegence. I can tell you this, break on oil is seldome used in the industry any more. When it is used it is not used for any length of time, we used to use it for the first 500 miles. On a flat tappet engine I do not like to run that long without dumping the oil. Cam break in lube has a minor amount of grit in it and I don't like all that crap running through my new mill. That said, this is a personal thing and probably off topic for this thread.

 

Crane cams doesn't recommend synthetic for run-in either.
"Caution : we do not recommend synthetic oil for run-in. We strongly recommend mineral oils with flat tappet cams to ensure proper lifter rotation. Flat
tappet cams have the lobes ground on a slight taper and the lifter appears to sit offset from the lobe
centerline. This induces a rotation of the lifter on the lobe and this rotation draws oil to the contact
surface between the cam lobe and lifter. Synthetic oils are too slippery and do not promote proper lifter rotation. "
https://cranecams.com.au/pdfs/CAM RUN IN PROCEDURE.pdf

 

..And neither does ISKY.
"Please note, Isky does not recommend the use of synthetic oils with any flat tappet camshaft especially during break in."

 

So what is different between “break in” oil or just conventional oil?

 

I thought everybody who is anybody on the Hamb knows that break in oil has some Bon Ami in it.

 

That’s funny. I’ve heard a few stories from my dads friend “back in the day”. Every thing from it worked, to stuck engines.
I’ll stick to a 25 minute run in

 

I always say, it's better to mix oils than it is t run low on oil. It is good to stick to one type/viscosity grade, even brand of oil; but when it gets to the point that you're running low, go ahead and mix. Whatever results from that is better than none at all.

So when a technical letter contains technical errors, how much credibility to you give it the rest of it?

First of all, this letter states that as of '04 government regulations have mandated "the complete elimination" of zinc/phosphorous anti-wear package, that is false. There is a chemical limit on the amount of zinc/phosphorous in certain viscosity grades, not a "complete elimination". And for other viscosity grades there is no limit. Strike 1.

Second, in the paragraph about synthetic oils, they talk about certain oil "with very low viscosity index numbers", then in parenthesis they give 0w-15 and 5w-20 as examples. Those are not viscosity index numbers, those are viscosity grade numbers, and they both actually have very high viscosity index. Viscosity Index is a rating of an oil's change in viscosity relative to change in temperature. An oil with a low viscosity index will have a great change in viscosity relative to change in temperature; and on oil with a high viscosity index will have less of a change in viscosity relative to change in temperature. See chart below that compares an SAE 30 oil with a viscosity index (VI) of 104 to an SAE 10W-30 oil with VI of 144.


So, these guys used the term Viscosity Index where they should've used Viscosity Grade. No big deal? Maybe, but I can assure you that anyone that is worth listening to about oil knows the difference between viscosity grade and viscosity index. And they know that not all zinc/phos has been removed from modern engine oil, there has just be a limit placed on the amount in some viscosity grades. All of which means, these guys don't know what they are talking about, they are simply repeating what they've misheard before.

So how much value to place on the rest of the letter? Isky obviously knows camshafts, they know them very well. They just aren't as educated about oil.

 

Just to clarify, because people often misread things. I'm not disagreeing with them, (not agreeing either), I'm just criticizing the lack of information, and then when information is provided it's technically wrong, that doesn't look good to me. YMMV.

 

And I'm sorry, I can't let this one slide either. So "slippery" is not a technical term. They are not wrong here, I just can't take the verbiage used. There is a characteristic of lubricants called the "coefficient of traction", or simply "traction coefficient", which is a measurement of the ability of an oil to transfer load from a moving part to a non-moving part. Synthetic motor oil tend to have lower traction coefficient, which is why they can run cooler and improve gas mileage; and as Crane says could cause the lifter to not rotate on the lobe. Poor language, but good science, and this seems a legit concern to me, minus an alternate point of view.

 

You and I are in agreement, and what you say is exactly right. Thats what I was trying to say, but perhaps I didn't do a good job explaining it.
The break in oil is mineral based with zddp and specifically made to let parts seat in. I think thats the best choice for a newly assembled engine.
Then I switch over to full synthetic to take advantage of its slippriness (had to look that spelling up) for the rest of the engines life.

I think the confusion is from my comment "I do not know if the slickness of synthetic will/can prevent rings seating" . That was directed at the belief that synthetic is so slick that it prevents rings from seating if used during the break in period. That was meant to mean that I do not know that to be true OR untrue, but I don't take that chance. Sorry for the confusion from my poor explantion.

 

No, I believe @Blues4U is saying that "the lore" is telling us two diametrically opposed things-- that break-in oil is 'easy' on cam lobes and 'hard' on rings (as in, helps them to seat instead of just being 'slippery')... and that it cannot be both things at once, and therefore the lore is just that... not scientifically valid.

Also... slipperiness.

 

Concerned about the cling factor of full synthetic in my flat tappet engines during Wisconsins long winter storage from November to April, been using mineral base with an additive to help keep a coating on the cam.
Also wonder about if mineral oil protects better than synthetic if contaminated with fuel from sticky floats, chokes ect.
I run Mobil One in our newer fuel injected engines with good results, 222,000 miles on a 1.4 so far

 

OK, let me take another crack at this ...........

It isn't. With the mineral based break in oil you want "wear" on both the rings and the flat tappet cam/lifter interface. Here again, terminology suffers in the explanation. The wear is an engineered design feature of " seating" the components together.

Yes, I believe synthetic oil is better at preventing metal to metal contact, and thats why I believe its not a good choice for break in.........you need to seat/seal the flat tappet cam/lifter and rings.

I don't believe the mineral based break in oils are better at preventing metal to metal contact. They encourage it in a controlled (hopefully) manner. Its like the "lapping" process used in machining. You allow a certain amount of friction/wear/seating by controlling the "lubricity" and the abrasive contained within the medium.

Another thing is that I don't know how the manufacturers are dealing with the ring seating vs synthetic oil. As far as the cam and lifters , I don't believe they have any problems because of the roller cam/lifter not requiring the same seating of parts.......and no need for rotation of the lifter. In Moparboy's posts, it was stated that synthetic oil was so "slicky" that the lifter might not develop sufficient friction between the cam and lifter to rotate. Never heard that before, but I guess its possible. Like most people on here I don't really have direct knowledge of any of this stuff..........I'm just an internet wannabe. So the stuff up above is my current "OPINION" based on "things I read on the internet.

 

LOL in the engineering world, when calculating flow, we use the term (and also tables by the same name) friction coefficient. It is even used that way when figuring oil passage through a tube or orifice.

Interesting the differences in terminology when crossing from one discipline to another.

 

I run mineral oils in my old cars and not modern synthetics based on advice from my engine builder / mechanic, he was building engines and race cars well before I knew him . My DD uses modern synthetic oils.

 

I can add this bit of info. I drove a bulk oil tank delivery truck for Valvoline. When the temps were in the single digits with conventional oil the delivery pump on the truck sounded like I was pumping marbles it rattled so bad . When I switched to a synthetic tank it would smooth right out and quiet down. I used to imagine that same noise in my street car oil pump and the damage being done. Nothing you fellas didn't already know but hearing the difference was amazing.

 

Had an engine rebuild shop in the 80s, best thing for the engine is to keep the oil clean.

 

To close out the thread:

Use oil.
Use the proper amount of oil.
Use the grade of oil that the manufacturer of your engine recommends.
Use and oil high in ZDDP if you have flat tappets.
Use a good quality oil filter.

And, done.

 

Yup, and the next one about how to wash a barn find!