Oil essay
Maybe this should be titled "Essay on Lubrication"????
oilessay.htm-51C
© copyright, 2011, R. Fleischer
Here is information that might be useful in understanding how oils, especially engine oils, but not exclusively. REALLY operate/function; and what things you should consider in selecting oils. This is not some strictly engineering treatise on the subject.
Engine
oils, synthetics, additives, and wear:
Some additives are
put into base stock oils to help form better 'thin oil films', so the
oil is not pounded-out by impact forces. Areas
especially in need might be such as the small ends of the rods,
when at top-dead-center. Very
LITTLE engine wear is from dynamic friction...that is, from
rotating, constantly shearing movements. MOST wear is
from transient loads, such as at the cam lobes.
Regarding cam lobes, the Airhead engine is of
the type of engines that professionals describe has having
adverse
"slide-to-roll" ratios, and of
high loading. This type of engine is common to
some you know about, that have "flat-type" cam/rocker/follower systems, such
as on the old VW Beetle, the Porsche 356, early Corvette's...and even the Ford Pinto.
Owners of these types of vehicles are too often well-aware of
REAL engine
failures from wrong types of oils. In particular camshaft and
lifter wear. Today, modern car engines
are so precisely designed and manufactured, that very light oils with no or
limited ZDDP additives can be used. NOT SO with these early engines.
Much has
been said about synthetic oils, and mostly it is about how much
better they are than petroleum oils. While based on SOME
facts, many are misleading. Especially misleading is that
oil change intervals may be increased GREATLY. While
relatively true (doubling, perhaps) for the lubricating
qualities, it is NOT true as far as the additives for swelling
the seals (granted, most
modern seals are neoprene or silicon
types, hardly needing specialized swellers); and for doing other
things that additives need to do. Particularly, for Airheads,
one of these protective
additives is some form of ZDDP for flat tappet (flat cam follower) type
of operation. There are a lot of additives in oils.
Some are to protect against absorbed moisture and many MANY other
problems. SOME additives 'burn off' rather a bit too
easily, leaving the oil
without enough additives for many functions, not hardly just seal
swelling, rusting, and high loading areas (camshaft lobes, piston
rings, lifters....). This is particularly so with some cheaper
oils, and even with some high priced oils!
Many premium motorcycle oils are produced with synthetic
components, and may well have quality additives that will last a
lot longer than the commonly accepted 3,000 mile change
intervals. It depends CONSIDERABLY on how the motorcycle is
ridden....very short...3 to 5 mile trips in high humidity
perhaps...versus over 20 mile average trips...might be somewhat
the extremes to consider...MAYBE...regarding oil changes.
Changing too often is also, contrary to popular belief, not a
great idea. I know that sounds wrong....and the reasons are
complex, so I won't get into them here.
There is also a problem with the word synthetic.
Due to a lawsuit won by Castrol (presided and ruled over by what
I consider a rather technically poorly educated judge); a highly
refined type of petroleum oil, not REALLY a synthetic oil, CAN now be called synthetic.
So-called full synthetic oils that are on the market may not truly be high quality REAL synthetic oils.
Another problem is that, except for most of the specialty
motorcycle oil makers (who are better at NOT changing formulas), commonly available oils can...and
do.... have their
formulas modified, without the oil makers telling you.
Even the diesel oils like
Rotella-T and Delo and Delvac are all likely to have SOMEWHAT reduced
amounts of ZDDP in them now...and perhaps even less as time goes on. Your Airhead
NEEDS ZDDP; but does NOT need the very high dispersant and some other qualities of
d SOME diesel oils that MIGHT give problems. I simply cannot recommend
willy-nilly all modern diesel
oils for Airheads.
You might carefully select one, but I am not endorsing them any
longer. I do think that
probably
Rotella and Rotella-T, and maybe Delo, are still OK at the time I
updated this section (April
2011).
Modern car oils have little or no ZDDP,
as ZDDP tends to poison catalytic
converters. Modern car oils are typically energy saving (and so marked),
usually are in grade
5W30, as an example,...and are absolutely NOT compatible with your Airhead, and
not very good for your K bike either. There ARE some car engine
oils that DO contain friction modifiers (Energy Saving oil) that
MAY contain ZDDP, and yet are not starburst symbol identified.
This happens with such as SOME oil viscosity grades of Mobil 1, since it is made in viscosity
grades that are NOT car oil viscosity grades. More
information is in my 52B article
and my viscosity article.
Thick oils, that is, oils with
higher viscosities, have more internal friction, and CAN support
larger loads....but!...there's always a but, EH?......HIGH mechanical pressures of/in the parts themselves INcreases
oil viscosity. Yes, that is true; when oil is inside a
common bearing, and the bearing has lots of pressure (think conrods, as
one example), the effective oil's OWN thickness INcreases. This is so
even with the ends of the bearing open. This is a special
property of thin oil films, and has very little to do with
mechanical pressure in and of itself as a trapped medium.
Yes, I know this all sounds wrong.
A THIN oil is vastly easier to pump
and thereby get through the 'system', and INTO
VITAL AREAS QUICKLY and will support massively heavy loads. So,
a manufacturer uses tighter tolerances on those bearings, less
clearance and a thinner oil. This engine then needs more oil pump pressure, but that INcreases fluid friction. No entirely free lunch
here.
Another factor is high rotational speeds. The faster the surface speed, the more the oil is formed into a cushion, which then in turn allows even higher loading. There are many types of surfaces in our motorcycles. Some slide, some roll, some are fluid-based (I am NOT going to describe THAT!). There are a lot of forces and peculiar things at work. Oil and oiling/lubrication is HARDLY just some sort of liquid slippery stuff.
What folks often want to know is how lubrication really licks friction. You can't eliminate friction on a practical basis; but, you can minimize it. Many decades ago, schooling about friction was a sort of 'hills and valleys' type of discussion in describing forces that resist sliding motion. In other words, parts that looked smooth, really had hills and valleys and those caused the friction of the parts. That concept is rather obsolete now. It still applies, of course, to such as breaking-in of new piston rings, and most other areas to SOME extent. BUT, today, with modern fine-machining, the MORE important concept is ADHESION; and, lubrication engineers may sometimes find extreme problems that they need to solve: cold-welding of surfaces in contact. When a full film of lubricant separates surfaces, the only friction is from motion WITHIN the fluid. The fluid splits into layers. The top layer sticks to the surface, bottom layer sticks to the lower surface, and each successive layer travels at a lower speed, which shears the layers on either side. Oil "film" is what does the lubricating (not absolutely true on a REAL engineering basis, but good enough for us, here).
There are several types of 'oil films'. The hydrodynamic film is only perhaps 0.001" thick in a 1 inch bearing. Surfaces are kept apart by several functions, one of which is the hydrostatic function which is primarily from oil pressure from the oil pump. Thus, ONE of the purposes of the oil pump is to provide this 'keep the surfaces apart' oil pressure inside the bearing, etc. This is critical when there are slow heavy loads and also for starting up of the engine. Please be sure to read this small paragraph again....Oil slipperiness is not really involved! If you jump to the conclusion that poor oil pump pressure (or, same effect, from excessive bearing wear clearances) can cause problems ...you would be correct.
If the oil film starts gets too thin, metal contact is possible. Typically this
won't happen until the film is ten times less thick than that
0.001" mentioned. At that
point, additives like ZDDP, etc., come into their reason for
being in the oil. There are some other things to know. An example is that some
additives found in larger amounts, in diesel oils in particular, can cause
problems in HIGH SPEED engines. I won't treat that subject any more
in this article.
From what you have read so far, you will understand that you do
not want too thick an
oil, nor do you want too thin an oil. There is a REASON that 5W30 or
10W30...and likely 10W40.....are all too thin, for most Airhead
riding in mild temperatures. There IS a reason that 20W50 oil is most often recommended.
As parts speed up, other factors come into play. Required or specified oil viscosity can be juggled somewhat by the engine manufacturer. INcreasing viscosity will allow more loading, but then you get higher temperatures; and less immediate oiling. SPEED of the parts means faster shearing of all layers, but speed helps form a cushion, so higher speed means higher allowed loading (read that again, and think about what you have heard about 'lugging' an engine).
The best approach for a manufacturer is usually to use a reasonably low viscosity oil, with very good thinning characteristics (High VI, as one example), so it does not thin too much with temperature rise.
When the K
bikes came out, BMW contracted with Spectro Oils to produce an
oil specifically for the water-cooled K bikes. BMW then
promoted that oil, a bit slyly when for Airheads, which it wasn't the very best for,
although 'adequate'. The oil that Spectro
made for BMW was NOT Golden Spectro, and was not standard Spectro
either. In the very beginning of the K-bike
production, BMW was having
problems with the K bike starter sprag drive clutch not engaging, and finally
BMW
redesigned it. The newer type gave
less problems from oil type (NON-synthetics were the problem for
the most part, IF oil was a cause). Mobil 1 works quite
well, with almost no reports of problems with the early OR later starter sprag
clutch. What happened when the starter sprag clutch began
to fail is that it would slip after some sort of
unseen glazing film accumulated, and, perhaps, some loss of sprag
clutch springs tension;...and synthetic oils helped a lot....as did some synthetic additives in the
Spectro.
Some versions of Mobil 1 have
been found to work quite well in the Classic K-bikes. The Mobil 1
brand has 15W50 and 20W50 oils, and a few others, specifically
for motorcycles; although Mobil does change, irregularly, on what
is being sold. They do have an oil that was designed for
Harley Davidson's, there have been various names for that oil
over the years. It has a goodly amount of ZDDP in it, and
seems to be very good in Airheads. I prefer the 15W50 Mobil
1 for the K75, K100, K1100, K1200. However, some have used
that oil for the Airheads, and I approve of that usage.
Rislone, and a few other additives, perhaps the stronger CD2... used once
if needed.... would sometimes free up the K bike
starter sprag clutch, which is a VERY HIGH labor-charge job to replace;
and the part is not cheap, either. It is
actually possible to remove a failed later type starter sprag
clutch and clean it (PROPERLY!!!) and have it work again...but
few do that, due to the intense labor, if the cleaning does not
work well.
Here is a bit more on oil functioning:
Looking at extremely tiny irregularities in as-machined and broken-in surfaces, a LOW viscosity oil allows the oil to creep into very small microscopic areas. As the load increases, the oil is squeezed between the parts and dynamically increases the oil viscosity; which allows higher load carrying. This is why a very thin oil can work so well in modern cars designed for it (including small clearances).
This is why a 10W30 or a 5W30 or even 0W-30 (all being very popular or SPECIFIED today for cars) works so well in modern cars (which don't have flat tappet designs either), and modern engines last so long (precise machining, proper selection of compatible materials, expert design for lubrication, improved oils, etc.). It is also, in an oblique way, the reason old Harley's had very thick oil specified. I'm NOT putting Harley down here, just telling real facts. One could say the same thing about many old engine designs. ...and some of this really does apply to such as flat tappet old performance cars, Porsche boxer engines, and so on (and Airheads)....as I described earlier herein.
Oil wedging that is a fundamental principle that you might want to know about. Let me begin by discussing a rotating crankshaft; a crank journal, and a rod big end.
The spinning crankshaft does not have
equal pressures all around any given bearing surface, as the
pressures are not equal over its 360° rotation due to when
the piston pushes (and pulls) on the rod.
In the bearing area itself, the parts are ever-so-tiny
eccentric to each other...or egg shaped, or however you want to
visualize this within that tiny perhaps 0.001" bearing
clearance. This eccentricity drags oil into a
wedge-shaped layer between the journal and the bearing, which
LIFTS UP THE SHAFT, so the shaft is SUPPORTED
by the oil film. Yes, all this happens in that
oh-so-thin mechanical clearance.
Some shafts that rotate inside of bushings are supported by a wedging of
AIR...there is either NO lubrication medium like oil at all!....or just some to
allow no excessive friction as the parts START spinning-up. Most old-time
aircraft spinning instrument gyroscopes were like that...and many turbines work
that way (granted, with huge loads and oil to keep things cool). You
are probably sitting at a computer screen, and the computer next to you has a
FAN, and a HARD DRIVE, that use AIR bearings, to some extent or other.
Yes, air can be a lubricating medium. The
problem, of course, is before and just as the device starts
up....before the bearing is air supported.
An even deeper discussion would describe how oil leaves the wedge at a higher velocity
than it enters, and then a discussion of fluid back-up. Since oil can't really be compressed
into a smaller volume, its pressure builds up instead; but, this is not intended to be a course on
lubrication engineering and fluid dynamics....so I'm not going to
get too deep into things...just a wee bit more right here:
These things about rotating parts also occur in sliding parts....just not nearly as easy for me to describe and for you all to understand. So, no sliding discussions (pun intended!).
In a reciprocating engine like our Airheads and K bikes, the parts are changing direction, and the shaft is shifting position, and things move about until equilibrium, and the shaft essentially centralizes in the oil film...well, ALMOST! The oil film is squeezed, forced to move around the shaft, but the viscosity pushes back against this change, and that resistance ADDS to the load supporting capability....up to a point anyway. The high-brow term here is 'squeeze film'.
As rotational parts speed increases, there is a point reached where oil friction suddenly increases...a LOT. This critical surface speed is where the oil lubricating film starts ceasing to be a laminar flow (layer-like), and becomes a turbulent flow. This MIGHT give you some idea about why some race-bikes have oiling failures under some conditions. You can increase oil viscosity, or decrease it, you can change types of oil, you can increase oil pump pressure, you can do all sorts of things including changing clearances...but, there are limits for each bearing, and many a racer has found those limits!
Getting deeper into
how thin oil films REALLY work, on the molecular and micro areas,
is way too nerdy for even this article. It
would get into what is really meant by oiliness, adsorption, more
of hydrodynamic lubrication, how the film can be penetrated, and
so on.
When I studied
this sort of stuff, I kept all my notes; and my industry
information, and they are nearly 2 inches thick.
Lubrication is a VERY complex subject, it is still evolving.
I probably should quit here.
Probably bored 99.9% of you anyway.
ZDDP is important for Airhead engines. ALL ZDDP is NOT the same.
Zinc dialkyldithiophosphate is both an antioxidant and an antiwear agent, and
most formulations are somewhat volatile to a bit too volatile. As
the oil standards specified by car makers and the SAE, went from lower to higher
letters (SG to SM, as example), the oils had less ZDDP. Newer
standards reduce sulfated ash, phosphorous, sulfur, and, of course, zinc.
The reduction in zinc is to keep the $$$ catalytic converter from being ruined;
the other reductions were to lengthen the lifetime for the Oxygen Sensors on
modern cars and bikes. Most SM oils still contain some ZDDP, but in
a less volatile formulation. This prolongs cat converter life, but still
provides some antiwear protection for engines with high slide-to-roll ratios.
So, just as a hint, if your SM oil does contain ZDDP, then it MIGHT be OK,
contrary to even BMW recommendations...but you need to KNOW.
For sure see LAST WORDS, at the
end of this article...for a LOT more about ZDDP, ETC.
Oil drain intervals, etc: This is a vastly misunderstood item. My information comes from REAL industry experts, not just my personal opinion. It is true that car makers tests show that drain intervals of 7500 miles are OK, even more in some instances. NOT SO for your airhead, with conventional dino petroleum oils. NOTICE ALSO, that ...and this is hardly widespread knowledge!!......fuel economy DEcreases quite a bit after about 4000 miles...as oils burn off the protective anti-friction additives. You would NOT think that could be true, after all, you think (??) that the ZDDP, etc., does not even come into play until things are awful...but it is not so. There are quite a few things that degrade oil over time and mileage. This includes fuel dilution, contamination from combustion byproducts that escape, typically through rings leakage; incomplete scavenging of crankcase vapors; oxidation, and the shearing action of the engine's mechanical parts. For water cooled vehicles, it takes very little in the way of a cooling system malfunction, to shorten oil life.....and, a stuck-open thermostat is one of the worst things to have happen...the engine cooling water runs too cool, and so does the oil.
I have mentioned how not changing oils TOO often is better...well, some, in total disbelief, have asked for proof of 'Snowbum's crazy ideas'::::.......So, I say, briefly: ""oils, if properly filtered, can IMPROVE in some characteristics, as the miles pile up, and changing oil too often is NOT a good idea"". For just one of a number of articles on this, try: http://papers.sae.org/2007-01-4133/
Viscosity improvers may be depleted too soon, if you extend oil changes
too much. That means that 20W50 oil for your Airhead might become a 20W30!
...or something else.
In general, for Airheads, a 4000 mile change interval....provided it
is at least yearly...is probably OK. You might even go a bit
longer on a K bike, particularly if you use a quality synthetic such
as Mobil 1.
If you let your Airhead oil level fall below the half-way position on
your engine dipstick, it may be better to change the oil somewhat more often. Older
worn engines need oil changes
sooner! Diesel oils have a lot of
dispersants in them, to deal with the soot and particulate formation and greater
level of crankcase gases. A quality diesel oil, with ZDDP, may still be
the best answer to a relative INexpensive oil for your Airhead...but I can no
longer make specific recommendations....as I can't keep up with changes to
them. Another concern for oils is the moisture
that collects in oils in engines that do not come up to proper operating
temperature for a long enough period of time. If your typical ride is
under 20 miles, and certainly if under 8 miles, that means YOU.
Multiweight oils are generally vastly better than old-time single weight oils,
for a variety of reasons. Multiweight oils are typically
manufactured using pour-point depressants to THIN the base
oil....so it flows easily when cold. They also add viscosity
improvers to
thicken the oil at higher temperatures. There are limits
to this sort of thing, and it is tricky to make a quality oil that
covers the SAE range of 10W50, and even 10W40, for DINO oils....and
easier to do this type of oil compounding with real synthetics.
The Europeans...as of February 2009.... still
have much tighter specifications for their oils...especially car oils...than we
have here in the USA. Those who use Euro oils in their cars can
extend changes. Don't, for Airheads.
Oil recommendations for AIRHEADS:
For Airheads, due to the variability (I
think!) of some heat-treated parts, and due to the type of cam
and followers; I can recommend the
following oils:
(1) Mobil 1
V-Twin in 20W50 grade. You can usually
extend the drain intervals due to this being a full synthetic
oil. This oil can be pricey, and I am not sure it is
worth the money; but drain intervals, assuming longer touring
miles than city traffic miles, could be quite long, with safety.
This oil has plenty of ZDDP in it, is a good
formulation, in all respects. I have one big reservation
about this oil IN AIRHEADS.....you might get some leakage at the
seals. Not all have reported this. I don't use this
oil myself in my airheads.
Mobil 1 in 15W50 is probably usable, but I can't give a blanket
100% OK. BUT, if you want to use a synthetic, this is
likely one of the best.
(2) Golden Spectro 4 in 20W50...can also have SOMEwhat extended drain intervals, as it is a part-synthetic and I have
considerable experience with using this oil. This oil is a
bit expensive, but is of excellent quality. This oil also
has an excellent base stock. It is my favorite Airhead
engine oil. It's formulation has remained constant.
(3) BMW 20W50 NON-synthetic motorcycle oil. This is a
good oil, but not quite as good as the above oils.
(4) Valvoline 4-stroke motorcycle oil, in 20W50 (or 10W40 for
quite cold areas). Not as quite as good as (1) and (2)
but plenty good enough. The phosphorus content
is 0.103%; calcium 0.182%; zinc 0.112%; sodium 0.052%.
(5) Shell Rotella-T in grade 15W40; calcium 0.27%; zinc 0.135%;
phosphorus 0.120%. This is a good oil, can be purchased at
quite a savings, in bulk. It is often referred to as a
'diesel' oil, which it is. It is possible that the formulation
will be changed, but that is the latest laboratory test
information I have on it, and due to those tests...which also
cover other qualities of this oil, I think it likely quite decent
for Airheads.
(6)
I cannot recommend Castrol motor oils, of
ANY type EXCEPT for:
Castrol's 4T oil, (and Grand Prix
oil, which is the SAME OIL) in either grade 10W40 or 20W50, as
appropriate to your climate. These oils are SG rated and formulated.
Zinc component is 1100ppm; Calcium component is 1900 ppm; and
Phosphorus component is 1000 ppm.
The above oils MAY
especially pay for their cost, over the long run, if you keep the bike a
long time and for high
mileage.
Do NOT use cheap energy
saving (so marked, and probably have starburst symbol) car oils,
and particularly not in 5W30, 10W30, 10W40. If you make ONLY short trips (under
8 or 10 miles), change
your oil every
3 or 4 months. If you ride now and then for over 20 miles at one
time, you might be able to extend the changes to 6 months...or even a year. The Euro specification that is tighter and more
strict than what is in the USA, is ACEA-A3. Look for it on some products
in the USA nowadays. Do NOT use oils with the energy-saving Starburst
logo. Do NOT use the latest CJ-4 oil, as it is only so-so for our bikes.
Remember, if you use synthetics, that they are NOT all the same! Be SURE
yours has ZDDP, and a goodly amount, for your Airhead.
If you ride in
rather cold weather, below freezing, I suggest a lighter grade
than 20W50. 10W40 perhaps. Avoid the CAR grades....as they will very likely have characteristics that you do
NOT want.
Do NOT use cheap oil filters in your Airhead.
Use the two-part hinged filter, if you can.
Repeating:
I will BET that you NEVER have heard of this!....
Too frequent oil changes can INCREASE wear!! I
am not going to spell out why, and leave that to your imagination!...but,
it is true. Your gut tells you I am totally wrong, right?
...as noted above, try this (there are other more in-depth
articles on this subject):
http://papers.sae.org/2007-01-4133/
****DO NOT use K & N air filters!! *** .. if you want to know why, see the K & N filter article: click
Last Words:
Just what is ZDDP....ETC.:
ZDDP is zinc dialkyl
dithio phosphate. ZDDP was developed in 1930 to prevent
engine bearing corrosion. It was found that it has
excellent anti-scuff properties. It came into wide use much
much later. In the 1960s, high performance flat-tappet
camshafts were common. It was found that a zinc level of
0.07% was very helpful. Back in the 1960s, all
new camshafts were generally phosphate-coated, and together with
the ZDDP in the engine oil, the brand-new camshafts and lifters
were protected from premature wear, particularly during the
critical break-in period. As engines became more
powerful, and pressures on parts increased, the level of zinc was increased to 0.09%. Oils
changed too, becoming much more complex, and additives for
friction modifications, antioxidants, detergents, etc., became
common and more sophisticated. Fuel economy began to be of
some concern, and the zinc content was continually increased,
with premium oils commonly having as much as 0.2%....into the
1980s and 1990s.
Zinc Phosphate is not really a lubricant....UNTIL IT GETS QUITE
HOT. When two metal surfaces rub each other, the
microscopic top layers can be extremely HOT, yet the part be
quite cold in comparison. ZDDP is often called the
lubricant or protector of last choice. That means
that when the oil film fails, ZDDP should be taking over, giving
you some goodly added protection. The actual way ZDDP works
is not easily found in literature. When it gets hot
at the surface interfaces, it creates a phosphate glass on the
surface. Extremely thin, but it IS THERE.
It has been compared to a painter's primer coat. The engine
oil is the top coat in this scenario. YOU NEED A HIGH LEVEL
OF ZINC DURING BREAK-IN TO ESTABLISH THIS PHOSPHATE GLASS
COATING. You also need an adequate amount of zinc for
long-term cam, followers, etc., protection, even after the glass
layer is established. It is well recognized within the
performance engine builders community that a high ZDDP level is
very beneficial for roller camshafts, lifter bodies, lifter
bores, roller rocker arms...especially where high spring
pressures are used at the valves.........not just flat tappet
applications. ZDDP protects valve tips and pushrod tips.
Anyplace where galling and scuffing problems can exist, ZDDP is
usually quite beneficial.
ZDDP amounts have been reduced in car engine oils, or completely eliminated in some. That is because the zinc and phosphorus contaminate the $$$ catalytic converters. Phosphorus limits were lowered to 0.10%, and zinc levels were dropped also. In 2004 came the so-called Tier 2 emissions standards, and OEM warranties changed to 10 years or 100K miles, and phosphorus dropped again, to 0.08%...and zinc went down to 0.09%. The levels are even much lower now.
There is no question that, for modern engines, modern oils are VERY SUPERIOR. These oils are a big part of why engines can last 250K+ miles these days. Improvements in metallurgy and machining, even cooling of parts, and a few other things are the rest of the story.
The BIG problem is break-in of the cam and followers and other parts, when brand-new. For most Airhead owners, that is hardly the problem, since their engine's such parts were long-ago broken in, hopefully on ZDDP oils. BUT, the zinc (and phosphor to some extent) are needed continuously in Airheads; and if the cam, etc., was NOT heat treated well-enough, or perhaps not broken in on a proper oil....deterioration will set in. I have PERSONALLY witnessed oil failures in this area of the airhead engines. High spring loads compound the problems. In a nutshell, EPA regulations, SAE and engine makers and car makers have all 'conspired' against the type of oil YOU NEED for your Airhead. Luckily such oils are available, INCLUDING by means of a few quirks in the rules, which recognize only certain viscosity grades as 'car oils'.
Normally, Airheads break their engines in on a thinner grade
(10W40 perhaps) of SG type oil and then change oil to
perhaps a SG type in 20W50. There is a
break-in article on
this website. Yes, that was a hyperlink. You want proper ZDDP levels in your
break-in oil, and still in your regular oil after break-in. SOME airhead
owners are ANAL about break-in. Those that are in this
category will use some additives.
They may use a dedicated break-in oil, with a ZDDP additive; they
may use a coating on the cam, etc., at first start-up.
For the nerdy of you:
A non-detergent break-in oil could be a straight 30W or a 10W30,
plus a ZDDP additive. Your regular engine
oil needs to be AT LEAST 1000 to 1200 PPM of ZDDP.
You can also use more common oils and add ZDDP. Many
diesel oils contain adequate ZDDP, finding WHICH can be a fun
game. There are specialty oil makers who have oils
specifically for flat tappet engines, break-in and regular
running.
So, for the
EXTREMELY NERDY:
Joe Gibbs oils...BR and BR30. They have a special break-in
oil, with 2800 ppm zinc...!!!...this oil was developed for quick
break-in and dyno runs.
They have a BR oil in 15W50. These specialty
oils are often used where the oil is preheated, the new engine
started, and on the dyno right away. They
have a Hot Rod Oil, with 1200 ppm ZDDP, in 15-50,
10W30, etc. It is LOW detergent...did you know that HIGH
detergent levels can wash-away
the ZDDP somewhat? This oil has extra
additives for especially long term storage for classic
cars...rust protection, corrosion protection, etc. One change
a year for the typical classic car show type use.
The Joe Gibbs MicroZol BR and BR30 are good oils.
Brad Penn company. American Refining Group makes Brad
Penn Racing oils. They offer a straight 30W oil with high
levels of zinc and other antiscuff additives, called Penn Grade
1. ...specially formulated to help rings seat fast.
Royal Purple company...makes a Engine Break-in Oil.
ZDDP additives from such as Comp Cams (159 ZDDP additive).
Red Line has a high-ZDDP break-in oil additive.
Trick Flow TFS-9400.
Eastwood 50332Z.
Isky Racing ZDDP PLUS.
Mobil 1 has no special break-in or additive, but does make a OW40
with 1000 ppm ZDDP...and, of course, its Mobil 1 products that
contain lots of ZDDP, such as the 20W50 V-Twin oil; and the 15W50
oil, which, at least awhile ago, had plenty of ZDDP. Some
of these oils are listed in my viscosity article, or elsewhere's
on this site.
***A GOOD
rule of thumb for decades, and still good, is that you should
NOT use a full-synthetic oil for break-in....especially if new
piston rings were installed or a fresh cylinder honing job.
***Fully synthetic oils may not allow your
Airhead lifters to properly rotate!! I have NO direct
experience.
The cam, etc., will be broken-in within 500-100 or so
miles, and you can switch to a decent ZDDP-containing
non-break-in oil.
If you are very much a nerd...go ahead and coat your cam, etc.,
with a good zddp protectant.
***Under NO circumstances, but an emergency, EVER use an engine oil, NEVER EVER for break-in...and try to never use it at all....if the container has a API starburst symbol.
So; what do you use for a break-in oil? It is up to you. Frankly, I simply use 20W50 Golden Spectro 4 on Airheads. See my break-in article!
The following is exactly as presented, UNedited, except for where I added color for emphasis....since it is something important, not gotten into in my above article. I wrote this 11/16/2009 on the K-Tech LIST, regarding a question on ZINC content of engine oils. I leave it here for you to read, as the information is presented differently than the above article; and I expanded the reply beyond zinc, as you will see here:
I'm not a mechanical engineer, but an electronics
engineer...but I will take a wee stab at this, since I have
studied, written, and posted, so much on lubricating oils, etc.
I also am not going to do anything but one mention here ...of why
full synthetic oils are better for the old K bikes, due to the
starter sprag clutch problems.
This will be a reply about zinc (and zddp, and phosphorus, the p
in zddp). Without getting into the various types of zinc
additives (there are versions of ZDDP), .......the use of zinc
compounds in vehicle engine oils is no longer of all that much
importance in MODERN vehicles. HOWEVER....for many older
vehicles, there is, or certainly can be, a problem. Zinc is
being phased out of engine oils due to its slow, but accumulative
effect on the expensive catalytic converters used on cars, and
that are also being installed nowadays on some diesel engines.
At the same time, phosphorus has been reduced, and in some oils,
a substitute, a boron compound, is being introduced. The
trend towards 'no zinc' is going to continue, and eventually we
will see no or nearly no zinc in the engine oils used in cars and
trucks.
Right now, in the USA at least, only certain viscosity
grades of oil will fall under the regulations of no or diminished
zinc. Grades not used in modern vehicles seem to be exempt
from the no or minimal zinc. I explain that in the articles on
my website.
In general, the ZDDP problem does not exist, or is relatively
minimized, in the Classic K bikes...that is, K1, K75, K100,
K1100. There have been some reported problems in early
production, but I have no real data AT ALL to show any trends,
NOR just when BMW might have made changes to reduce problems.
The problem certainly does show up on the
BMW Airhead bikes. I think that in maybe 5 years or so we will
hear of more oil failures in old K bikes, as car oils change more
and more. In general, the problems show up on the
cam lobe faces and the followers/tappets of engines. This is an
area of the engine that is quite highly loaded. There is some
lesser evidence that the effect shows up on rocker arm tips (yes,
even those supposedly highly heat treated areas), and a few other
places. MANY owners of 'flat tappet' engines are only
too well informed of the problems. This includes early
Corvettes, air-cooled Porsche's and VW's, amongst others. Any
decent internet search will bring you to owner's forums...even to
factory literature!....telling you of oil failures, and what to
do to avoid it. It is not my idea here to get into why a
'flat tappet' engine is more likely to have a problem than a cam
that drives a cup follower (OLD K bikes.....). This isn't a
college-level course in lubrication.
ZDDP was originally introduced for the
purpose of oxidation stability in engines with plain
bearings...protecting the copper-lead material. ZDDP
still has that purpose, but it also has at least one other use.
It is the lubricant of last-resort, when two metal surfaces rub
each other....and the 'protection' begins just at or around the
time actual metal contact is about to, or does begin, that is,
the oil film is failing to protect as intended. For reasons far
beyond this reasonably short (??) reply, the wiping action of
cams and tappets are particularly hard on oils. Zddp is in the
oil to prevent oil film failure (or give protection if the film
fails). There is an article on my
website that explains in some detail just how oil really
lubricates rotating, slipping, and rubbing surfaces, and it is
far different than what many probably think; that is, the
lubrication is much less involved with slipperiness, for
example. It is not zinc, but phosphorus content that is the
biggest item of importance in ZDDP, as far as wear goes. The SAE
has published a well-known chart (to engineers) on the effect of
differing loads versus phosphorus levels (there are other charts,
zinc, etc....not important right here). Most of these types of
charts (there are a lot of them) are presented as lifter loads,
in pounds, versus zddp or Ph, and the criteria is scuffing of
parts. What is interesting about the charts is that the curve
is NOT linear, particularly so at LOWER concentrations of
phosphorus. At lower loadings, only a concentration of maybe
0.03% is needed. At higher loadings...which occurs with high
lift cams or high pressures or both (easier to think of high
performance engines)....concentrations of 0.08% are needed. What
is needed means that MORE than that amount is required, due to
burnoff of the additives, and for a safety factor. One last
thing on that concentration business. Way more than needed is
NOT good. The charts show that if the Ph concentration goes over
0.14%, then wear starts to INcrease. At 0.20%, wear is
definitely accelerating fast. This means that there is an
optimum range of ZDDP concentration (and, for the revised modern
oils, the Phosphorus concentration).
Cam lobe profiles also differ from engine design to engine
design. Some cams have relatively a fast acting 'ramp',
some do not, and some have lobe characteristics that are very
hard on oils. Cam lobes may look nearly identical to the casual
#1 eye-ball, but they are often vastly different, even when they
look the same, right next to each other. Cams and
followers/tappets also vary in heat treatment. It is my belief
that the oil film failures seen on some airheads, and likely some
K bikes, are at least partially...and maybe the major
cause.....due to the variability with the cam and followers heat
treatment. I know of some motorcycles with VAST mileages, run
on cheap car oils, that have had NO problems. I know of failures
from common car oils. Since 'energy saving' 'starburst
marked' oils have not been on the market long enough, I think,
for enough problems to be reported on motorcycles. I do think
we will see more and more problems reported. I think
this will slowly accelerate, as more riders do their own
maintenance on old bikes, and use the cheaper car oils, for
either convenience or cost or both. What you will likely
see with the oiling failure is scored cams and followers/tappets,
possibly microscopic (to larger) cracks in the surface. Actual
engine failure will occur on some engines.
ZDDP does not only provide lubrication when conditions get awful,
but versions 'activate' at differing temperatures. Surface
temperatures that have less to do with the temperature you could
measure of your crankcase oil. Differing versions are in, for
example, heavy-duty diesel engine oils. There are real reasons
some oils were specified for some engines and some oils forbidden
in others. This was very much a problem a number of years
ago. There are numerous European (and """Japanese""")
specifications for oil, as well as our U.S.A. SAE and API folks
(together with the oil companies AND THE CAR MAKERS) ideas on
labeling and specfications. I won't get into this. There
are "substitutes" for ZDDP used in many, if not most, modern
oils. They are NOT adequate for some engines.
The bottom line, however, is that when doing oil changes, it is
the owner's choice as to the brand, type, and grade of the oil.
Unless the engine manufacturer states otherwise, for warranty
purposes, at which point the Dealership cannot, or should not,
use an unapproved oil. You may....or may not.....get away
with using an unapproved type of oil in your engine.
K bike engine internals have a deservedly good reputation for not
needing attention, other than oil changes and rare valve
clearance adjustments, for huge amounts of miles...no matter the
oil. This is likely changing, and will likely change for the
worse as time goes on,
and more use of car oils is made. On the airheads, it is likely
a contributing factor already in some early engine work being
needed...and that will accelerate, fast.
Finally, directly regarding your question about "zinc" content in
engine oils. Zinc content is usually expressed as a percentage or
parts per million. Either way is OK. I will treat this subject
as regards ZDDP, rather than just zinc itself, or phosphorus
itself. For engines that really should have ZDDP in
them, my personal feeling is that concentrations near 1500 ppm
are likely optimum, and over 1800 is not needed and detrimental,
and under maybe 800 or 900 is not enough.
OH...and what oils does Snowbum use? I settled on one oil for
the Airheads, that I trust, so have not used any other oils for
decades: Golden Spectro 4, usually in grade 20W50. I use
only one oil for my K bike, a synthetic, Mobil 1, in grade
15W50. I don't bother to differentiate between the several
types, extended or not, gold cap or silver cap. I get it from
Wal-Mart in big jugs. Mobil also makes a 20W50 for V-twins,
that one is good too (airheads also), but I prefer a 15W50 for my K bike, and the
protection levels of the additives in the "Harley oil" is likely
overkill for the K. These are hardly the only good (IMHO)
oils available).
To all of you out there reading this: It is all YOUR choice. I
have only tried to inform.
Believe what you want.
YMMV.
Rev:
01/25/2007: slight revisions and editing for clarity.
Remove poor formatting.
01/22/2008: edit slightly for clarity
07/12/2008: minor clarifications
07/14/2008: more clarifications
02/27/2009: Update by adding the entire addendum #1, and making minor
corrections otherwise, in line with changes by SAE, etc.
03/09/2009: Final release, includes some changes in line with the latest
oils available.
08/09/2009: updated
11/16/2009: Add last section
01/21/2010: minor updates and clarifications; add script to
code
04/13/2010: updated
04/21/2010: Add to section on ZDDP
06/18/2010: Updated the airhead oil recommendations to
include the caveat on Mobil 1 V-Twin oil, and changed the
commentary slightly for the Spectro GS4 20W50
09/01/2010: added hyperlink to SAE article
11/12/2010: slight updating, mostly for clarity and poor
grammar.
11/18/2010: add ppm of zinc for 4T oil
02/24/2011: was 52C
04/10/2011: Fix K & N article internal hyperlink and clean
up entire article SOME
© Copyright, 2011, R. Fleischer