The ZINC
- PHOSPHOROUS Problem Part 1.
Researched by Karl Schluter, Copyright.
As a lot of you will know the plan is to reduce and even
perhaps, remove Zinc and phosphate from our motor oils. Why should YOU care?
Well as the levels have come down, camshaft companies and engine builders
worldwide started to have camshaft wear reports like cam lobes going flat and
metal filings going through engines etc.
Varies reasons were given but the main problem is the older
Flat tappet camshafts and lifters need the higher levels of Zinc to last, (this
means Zephyr 4-6 engines or any non Roller type lifter/flat tappet cam whether
solid or hydraulic). Increased bore wear on normal engines where the piston
changes direction (the top of the bore and bottom of the bore) are also showing
more wear in the worse cases. Engines running high valve spring pressure in the
performance car field showed the first failures of cams. Later air cooled and
older rebuilt engines started failing too as the camshaft was run in.
There are ways around the problem, race oils are not all
affected plus some diesel oils (for a while at least) have also been used ok.
Also while oil companies don’t like it, additives can be used, I have run cams
in with Wynne’s Gear oil treatment and GM EOS works as well, both run in the
engine oil. STP has a Zinc rich product as well.
Why are the oil companies doing this? Well the Zinc and
Phosphorous clog the catalytic converters on later cars so the car companies
are mainly behind this it’s said; whether they are I don’t know.
Diesel cars etc will get catalytic converters soon (2007)
so the Zinc level in that oil will go down too. Some do not like the idea of
running diesel oils in our petrol engines either, too much detergent can be a
bad thing in a older, run in petrol engine however others have used it fine and
as you will read below, some engine builders and cam companies suggest it. I
was told on the 0800 number from one oil company that better additives are
being designed for this problem, I wouldn’t hold your breath while all the
newer engines are running roller lifter camshafts ! (Note: A roller lifter has
a wheel like on a skate board that runs over the profile of the camshaft lobe,
a great design that allows the same lifters often to be reused on new camshafts
as well as better mpg etc often, however the lifters must be guided or tied
together to make sure they don’t turn sideways!).
If re-powering you car, do fully consider an engine fitted
with a roller camshaft.
What to do with you pre-run in Z car engine? I would use a
top spec oil (read the Zinc ratings below) and if really worried the race oil (OIL
PRO GT 20W50HP) or a Zinc rich additive added to the engine oil.
If running in a new flat tappet cam in, have a few helpers
and check the basic things like the amount of petrol at hand (fill the carb
through the float bowl vent) and bleed the air out of the cooling system. If a
problem comes up shut the engine off and fix it.
· 1,Run the
recommended cam lube with the above oil choices mentioned in the oil company
emails in this article. NO synthetic oils!
· 2, Have
the engine set to fire right away (You haven‘t set the timing 180 degrees out
have you….), excess cranking will wipe cam lube off the cam lobes regardless of
removing the plugs and cranking it over for oil pressure.
· 3, I run pre-heated
water in the engine, the oil additives do little until they reach temperature,
every bit helps!
· 4, If
running multi valve springs, run the cam in with just the Outer Springs,
· 5, Always
grease the vanes or rotor in the oil pump on a fresh engine to get quick oil
pressure up, I use Vaseline (no rude jokes please!).
· 6,Leave
the multi carbs off, start up with a know induction system.
· 7, On the
Z engines there’s a Brass screw/plug that can be used as an oil fill next to
the oil filter/distributor.
· 8, Pre
fill or soak the oil filter (yes I know its messy).
· 9, Make
SURE the oil feed tube to the rocker gear is fitted with its O rings to the
rocker stand and lower block tube (look inside the side plate-do it!) the
returning oil up there splashes the cam as it drains back down as well.
· 10.Bring
the engine up to no further than 2000-2500rpm and vary the rpm below that for
good full-length cam splash. DON’T let the engine idle, Run for 20min or so
then swap out the oil and filter (I cut my filters up to check for metal,
copper, iron etc).
Note: All the above may seem to be getting carried away,
however you only get ONE shot at running in your cam. Compare the extra time
with the price of repairing a costly engine rebuild after cam iron has gone
through it……….).
Below are letters I received after contacting the Oil
Companies, (Nothing much from Mobil Oil NZ sorry, their tech guy wasn’t aware
of the problem and said he’d wait until customers got back to him, he did
however suggest Mobil Super HP 20w50 as the Zinc was still present at this time
-2007).
James from Caltex:
Hi Karl - thanks for your inquiry. There have been a lot
of changes in
engine oil technology since 1972, which means there are many choices and
options that simply weren't available back then. Various engine
builders have their own theories and preferences, which tend to fall
into two camps:
1 - Stay as close to the original makers specifications. The problem with
this is that the expectations of oil quality, oil drain intervals and engine
life were a lot lower than is tolerated today. This may not be a major concern
for vehicles that are only in light service or show cars. Also, it may be very
difficult to get oils of such low quality. There are some small boutique
companies that make oils available for vintage vehicles to these older obsolete
specifications.
2 - Use
modern engine oils to reap the benefits of the newer technology. There are
definitely some issues to consider with this, but generally I believe this is
the best option.
There are two main issues to consider: viscosity grades (how 'thick' or 'thin')
and performance grades (additive chemistry). Viscosity is the first defence
against wear: if the oil can keep metal surfaces apart, no wear occurs. Additive
chemistry is the second defence against wear: if the metal surfaces are forced
together, it's better to have a layer of additive in
between them to reduce the wear. (Additives do a lot more than just wear
protection, but I’m addressing your concerns about valve train wear in
particular). The Society of Automobile Engineers (SAE) developed the engine oil
viscosity grades that we use today. Prior to 1960, these were mono-grades
because the concept of multi-grades hadn't been invented. As far as viscosity
is concerned, there are two basic extremes that need to be covered: will the
oil get too thick at cold start up? And will the oil get too thin at maximum
operating temperature? (Oil thickens up when cooled, and thins down when
heated). The SAE developed Winter and Summer grades to cover all conditions. In
the Winter, you might use an SAE 10W, 15W, 20W etc to ensure the oil didn't get
too think and un-pumpable at sub zero start-up. The lower the 'W' number, the
more fluid the oil remained at colder temperatures. The summer grades are
measured at 100 degrees Celsius, so an SAE 20, 30, 40 or 50 might be used for
hot operating temperatures. The higher this number the thicker the oil,
allowing higher temperatures before the oil got too thin. During the 1960's,
oil technology was developed that allowed an oil to meet both the low
temperature requirements of a Winter grade, and the high temperature
requirements of a summer grade. The American Petroleum Institute (API)
developed the engine oil performance categories. For petrol engines, they
developed the "S" or Service series, and they started off with an
alphabetic sequence (SA, SB, SC, SD etc). As they developed newer and better
technology, they developed the next category. The improvements were always in
the direction of keeping engines cleaner and reducing the amount of wear. In
1972 the highest API category was API SE. For warranty protection of new 1972
American engines, API SE was typically required. Although multi-grades had been
invented by then, the early multigrade technology
had some teething problems, so mono grades such as SAE 20 or SAE 30 were quite
common (depending on climate and temperatures). In 1980 the API SF category was
developed. This was a major milestone in engine oil technology, and the level
of anti-wear protection was significantly improved. API SF remained the highest
category during the 1980's, and typically the cheapest engine oils on the
market meet at least API SF. Since 1990, there have been a host of
improvements, and currently we market API SL rated engine oils, and API SM is
not far away. So - when considering a suitable engine oil for pre-1972 engines
"in sound or new condition", I personally would choose a good
multigrade, with the highest API category possible. This would give performance
that was undreamed of in 1972. You raised the concern about modern engine oils
perhaps not having sufficient anti-wear protection for flat tappet cams. I
don't believe this is the case, if an appropriate viscosity grade is selected.
If we consider a 1972 engine, during warranty this may have used an SAE 30, API
SE oil. Any readily available modern oil will be at least API SF, which ensures
a much higher level of anti-wear protection than was available when new. An SAE
20W-40, SAE 20W-50 or SAE 15W-40 multigrade will give protection to a
mono-grade SAE 30. This is because at 100 degrees, any of these multi-grades
are significantly thicker than an SAE 30 at 100 degrees. At higher
temperatures, the difference is even more extreme. The mono grades simply thin
down too rapidly. They also thicken up excessively at cold temperatures. An SAE
30 might appear thicker at room temperature than a multigrade, but what is
important is what happens at the extremes of hot and cold.
You raised the issue of catalytic converters, which is a relatively recent
concern. It's true that catalysts can be damaged by excessive phosphorus, so
this means that oil formulations (and recent API categories) place limits on
the amount of ZNDTP anti-wear chemistry that can be used. However, the old
zinc/phosphate based anti-wear additives are not the only way to achieve
anti-wear chemistry. Newer ash-less additives are being developed, and modern
engine oils still meet the tough anti-wear requirements while also maintaining
the life expectancy of catalysts. For this reason it isn't appropriate to
compare the anti--wear properties of an oil by considering the zinc content
alone. Some of these concerns about modern engine oil chemistry are raised by third
party oil additive companies, who need to tell such stories to market their
unnecessary products. The API, the engine makers themselves, and other
standards organizations are spending millions of dollars in research and
development to make engine oils better. Generally, the modern oils benefit the
older engine designs, and there is no need to seek out low quality oils, or to
add extra unnecessary additives.
These comments apply to older engines in good, clean or rebuilt condition. If
these engines have been in storage for a long time, and were last used with API
SE oils or lower, they will be rather dirty. They may not have good filtration,
and could easily have layers of sludge in the sump and there may be extensive
wear in the rings and valve guides that is being masked by deposits that
weren't shifted by the low quality oils. In that case, converting to modern
high detergent oils might clean the engine out too quickly, blocking filters
and
exposing wear. There might be a good case to seek out very low quality oils in
these rare cases, to avoid problems. Also - leakage in vintage engines can be
an issue. If leakage is a
problem, I would tend to choose a heavier multigrade, e.g. SAE 20W-50. But if
leakage isn't an issue, the lighter multi-grades offer benefits of reduced
friction and easier cold starting. Most wear and tear takes place at cold
start. (Check my note at the bottom of this Oil Article-Karl). If an engine
originally used an SAE 20, then most modern multi-grades will work. You simply
have to ask these two questions: will the oil ever be too thick? And will the
oil ever be too thin? If we consider an SAE 10W-30 - it can never be too thick,
because if an
SAE 20 was ok, an SAE 10W is more than ok. It can also never be too thin,
because if an SAE 20 was ok, and SAE 30 is more than ok. The only concern is
perhaps whether the old style seals will leak. (If so, they would leak more
with the original SAE 20, which thins out quicker with heat).
For typical NZ temperatures, the SAE 15W-40 grade is usually most appropriate.
If leakage or oil consumption is a problem, the SAE 20W-50 might be more
appropriate, at the expense of extra friction and lower fuel economy.
Caltex products that might be considered for these older engines are:
Premium Five Star SAE 20W-40 (API SF)
Havoline Motor Oil SAE 15W40 (API SG
Havoline Formula SAE 15W40 (API SL)
I trust this information is useful,
Regards, James Cull
Caltex Customer Services
Chevron New Zealand
0800 733 835
The ZINC
- PHOSPHOROUS Problem Part 2.
Researched
by Karl Schluter, Copyright.
Here is the second part of the article, as we get deeper
into the subject of this problem:
This is another letter from James from Caltex after I
better explained my concerns of cam and bore wear in regards to the removal or
lowering of Zinc/phosphate in our oils:
Thanks Karl
I’ve obtained some
zinc level results from our laboratory for recent reference samples of new oil:
Caltex Supreme 5 Star SAE 20W-40 - API SF - 407 mg/kg
Havoline Motor Oil SAE 20W-50 - API SG - 785 mg/kg
Caltex Havoline Formula SAE 15W-40 - API SL - 766 mg/kg
Caltex Havoline Semi Synthetic SAE 10W-40 - API SL - 1031
mg/kg
Delo Gold Multigrade SAE 15W-40 - (diesel engine oil also
meeting API SJ for petrol) - 1289 mg/kg
Delo 400 Multigrade SAE 15W-40 - (diesel engine oil also
meeting API SL for petrol) - 1146 mg/kg
You can see that the cheaper oils meeting the lowest API
specs tend to have lower zinc, which is why - as a general rule - I would
always prefer the more recent API specs. They are more expensive, but you are
getting more (and better) additives. Even the older engines can benefit from
this - and it is certainly safer and better than purchasing a third party
additive which might have unexpected complications.
As I mentioned before, the zinc content is no longer the
best way to measure the anti-wear performance of an oil. This is because of the
newer ash-less additives that achieve their function without using metallic
based chemicals that leave a residue (ash) when burnt.
Also - the quality of the base oil (whether mineral,
synthetic or blend) also determines how much additive is needed. The higher
quality oils, especially synthetics, have naturally better properties and often
need less additives to meet the requirements of the API wear tests.
The engine makers usually decide what level of protection
they need, and they have a lot of input into the API test procedures.
Cam shaft companies are often involved in modifying engines
for higher performance - or even simply reboring/rebuilding an engine can mean
that the design parameters are changed a little. Sometimes the new parts that
are available are slightly different, so it's quite possible that camshaft
companies can be dealing with problems that weren't encountered by the original
maker. I would certainly not argue with people with experience in their
particular field. It is probably a good idea to consider using the higher zinc
content oils, and even perhaps the heavy-duty diesel engine oils that have good
petrol specifications.
The main issue with using diesel engine oils in petrol
engines is that the diesel engine oils tend to have greater amounts of
detergents too. This is not a problem in new or rebuilt engines - it keeps them
very clean. It may be a problem in older engines that have existing wear, and
where deposits are masking this wear. Sometimes introducing a higher detergent
oil can clean them out so well that they start burning oil. If that happens,
moving to a thicker multigrade with lower detergent can help to plug the gap.
Regards,
James Cull
Caltex Customer Services
Chevron New Zealand
0800 733 835
The Below is a email
from Lance at Castrol after I quizzed them on this problem:
Hi Karl
As discussed, here is some information regarding flat
tappet cam engine oils. We recommend Castrol Edge Sport 25W-50 for use in these
types of engines.
Castrol Edge Sport 25W-50 has an API SG rating and has Zinc
content of 0.116% maximum and Phosphorous content of 0.106% maximum. Attached
is the media release for the Castrol Edge Sport 25W-50 and below is some
information as discussed with one of our customers regarding ZDDP content of
engine oils.
"Further to our discussion regarding flat tappet cam
wear and ZDDP, we contacted one of our technical guys in Australia and he
explained to us that the Castrol Edge 25W-50 went through some rigorous cam
wear tests, done by a guy who specializes in modifying cams etc, he tested over
30 to 40 different oils and the Edge 25W50 was one of the best oils in cam wear
protection performance.
He also discussed the use of diesel engine oils, which has
more ZDDP, in this particular application and he pointed out that although some
diesel engine oils do have more ZDDP they also have a lot more detergents,
which compete for the surface area as well. Tests were also done with a diesel
engine oils which had high Phosphorous and these oils had worse cam wear
results than oils with lower Phosphorous.
As discussed with Neil the most important factor when
running in engines is that the oil must not be cold, the oil needs to be about
80 degrees Celsius or above to get the zinc anti wear additive activated, at
low temperature the zinc anti-wear additives are not fully activated and this
causes the cam to have metal to metal contact resulting in wear on the cam.
Also, running the engine at low idle also causes extreme wear to the camshaft,
the engine should run at around 2000rpm and the oil needs to get to around 80
degrees Celsius. Engines should also not run too high initially this will add
increased load on the cam which would result in wear .On assembly of the cam
you could also apply a light film of moly grease (SBX 2) to the cam lobes so on
the first few revolutions of the cam it has lubrication on the surface. The
first 10-15 min is the most critical, so you would need to run the engine at
fast idle between 2000-2500 rpm and the oil temperature needs to get to at
least 80 degrees Celsius."
If you have any further queries please do not hesitate to
contact me.
Kind Regards
Lance Goosen
Castrol Technical Services Engineer
Ph: 09 639 0000
Fax: 09 639 0100
Murray Reid from Pennzcorp suggests the OIL PRO GT 20w50
HZHP
Zinc 0.200%
Phosphorous 0.180%
By Weight
This oil is made with Flat tappet camshafts in mind!
If 20 litre amounts are bought, a very good trade price can
be done! (CLUBS?)
PENNZCORP 0800-761-761
Here is a letter in answer to a reader in the US HOT ROD magazine:
Quaker State engineer Mark Ferner said zinc’s extreme
pressure qualities also aid in reducing piston ring-to-cylinder bore wear at
BDC and TDC, where the rotating assembly sees an abrupt change in velocity and
direction. Besides its extreme pressure protection, multifunctional zinc also
functions as an antioxidant. That is, things exposed to heat and oxygen are
subject to oxidation. In the case of ferrous metal like iron, oxidation causes
corrosion, which we see as rust. As applied to motor oil, Ferner said as the
“heat accelerates oxygen, the oil starts to oxidize and thicken, changing into
other molecular combinations. As the oil thickens, it forms deposits or
varnish. In motor oil, the antioxidant additives first sacrifice themselves to
prevent this oxidation from occurring, but if they get overwhelmed, the oil
eventually turns into a hard, crusty sludge.”
In its antioxidant role, zinc fights heat build-up in
various hot spots like the piston-to-piston ring interface and the underside of
the piston itself. Oil can accumulate in the honing crosshatch marks in the
cylinder bore where it is exposed to combustion temperatures as high as 400-450
degrees F, a prime candidate for oxidation if not protected. Today’s modern
reduced-zinc passenger-car street oils contain other dedicated antioxidants to
make up for the loss of zinc.
The potential zinc downside is that in theory, an engine
with excessive blow-by could accumulate zinc deposits in the combustion
chamber, potentially becoming a detonation magnet. But Ferner maintained, “You
would need a fairly good amount of blow-by to really be bad for the chamber.
There use d to be 1,400-1,500 zinc ppm in (passenger-car) motor oils, about
where (Shell) Rotella (diesel-truck) oil is now. We ran those high levels for
years and years and never had a problem with chamber deposits building up. Zinc
accumulation mainly affects oxygen sensors and catalytic converters, which are
very sensitive to the ash that may accumulate on them.”
Regarding a potential reaction between aluminium and zinc,
again, in theory, when dis-similar metals come in contact with one another, a
phenomenon known as galvanic corrosion can occur. When this happens, the
least-noble metal acts as an anode and will corrode preferentially compared
with the other, less active, cathodic metal. A common example we’ve all seen is
using stainless steel bolts and washers to retain an aluminium intake manifold.
After long-term use, if you remove the bolts and washers, the aluminium surface
underneath those washers will be corroded because aluminium is less noble than
stainless steel. A solution would be to use zinc or cadmium-plated washers
instead of stainless washers. The plated steel washers then become the least
noble material of the three in contact, sacrificing themselves to protect the
critical parts. (Of course, they’ll end up looking ugly and need to be
replaced, but that’s better than ruining an expensive intake.) In the case of
zinc additives versus your aluminium block, Ferner reported “no adverse
reaction between aluminium and zinc at the levels we are discussing. Fourteen
hundred ppm would be 0.14 percent by weight - it’s insignificant.” Actually,
its even less than that, since “the zinc additive is not free
metallic zinc or powder, its part of a zinc/phosphorous/sulphur compound, so
really its only about 0.06-0.08 percent by weight” of the motor oil brew.
Below is a few links to the BEST articles I could find.
NOTE: They are NOT my own work.
http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/index.html
http://www.lnengineering.com/oil.html
http://go.mrgasket.com/pdf/cambreakin.html
http://www.repairfaq.org/filipg/AUTO/F_oil_facts.html
http://theoildrop.server101.com/forums/ubbthreads.php?Cat=0
On a side note I run a system in my car the gives oil
pressure before the engine is cranked up, it’s a basic system that can be
easily brought and I can get 30psi before cranking months after the engine has
been turned off. Also it works better than ANY gated sump and the sump oil
level can be lowered for less windage. If anyone is interested contact me at avocalea@xtra.co.nz
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article