With concerns over reduced zinc and phosphorous levels in current motor oils, what would be conventional (non-syn) motor oils recommended for our vintage, air cooled, flat tappet cam Brit bike in 20W50 weight?
Understanding Zinc...
Thanks to BITOG data I think we finding the single most common
misunderstanding about motor oil is that higher zinc levels provide
greater wear protection. fact is more zinc provides longer wear protection...
but thats a moot point given the short oil change intervals owners
favor...
Zinc is not even a lubricant until heat and load are applied. Zinc is
only used when there is actual metal to metal contact in the engine.
At that point zinc must react with the heat and load to create the
sacrificial film that allows it to protect flat-tappet camshafts and
other highly loaded engine parts.
Quote 540Rat
So, modern low zinc oils CAN BE USED SAFELY with flat tappet cam
setups, even in engines with radical cams and high spring pressures.
Simply choose from the higher ranked oils on the list at the end of
this write-up, and you’ll be good to go. I know people who’ve been
using modern low zinc oils in High Performance flat tappet set-ups for
a long time, and they’ve had no issue at all.
Zinc is used/sacrificed in very small quantities at time, so the total
amount present in your oil does not change how much wear protection
the oil provides, as long as you don’t run out of zinc. “Lab Testing”
and “Wear Testing” analysis proves/confirms that more zinc provides
LONGER wear protection, NOT MORE wear protection.
To make a informed decision like an expert you have to understand that
additives like Zinc and Phosphorous are used/sacrificed in very small
quantities over time, so the total amount present in your oil does not
change how much wear protection the oil provides, as long as you don’t
run out of additives “Lab Testing” and “Wear Testing” analysis
proves/confirms that more additives provides LONGER wear protection,
NOT MORE wear protection... just follow the oil change interval
tested and approved by Yamaha's engineers and your prized R1 should
meet and exceed your mileage expectations...
Zinc is used as an extreme pressure, anti-wear additive. But, zinc
“DOES NOT” build-up over time like some type of plating process. For
those who have actually taken an engine apart that has been running
high zinc oil, you know that you don’t find a build-up of zinc that
looks like some sort of coating or sludge build-up. Zinc does NOT work
that way. And zinc is not even a lubricant until heat and load are
applied. Zinc is only used when there is actual metal to metal contact
in the engine. At that point zinc must react with the heat and load to
create the sacrificial film that allows it to protect flat-tappet
camshafts and other highly loaded engine parts.
More from Flat Tappet know it alls...
1. Well known and respected Engineer and Tech Author David Vizard,
whose own test data, largely based on real world engine dyno testing,
has concluded that more zinc in motor oil can be damaging, more zinc
does NOT provide todays best wear protection, and that using zinc as
the primary anti-wear component, is outdated technology.
2. The GM Oil Report titled, Oil Myths from GM Techlink, concluded
that high levels of zinc are damaging and that more zinc does NOT
provide more wear protection.
3. A motor oil research article written by Ed Hackett titled, More
than you ever wanted to know about Motor Oil, concluded that more
zinc does NOT provide more wear protection, it only provides longer
wear protection.
4. This from the Brad Penn Oil Company: There is such a thing as too
much ZDDP. ZDDP is surface aggressive, and too much can be a
detriment. ZDDP fights for the surface, blocking other additive
performance. Acids generated due to excessive ZDDP contact will
tie-up detergents thus encouraging corrosive wear. ZDDP
effectiveness plateaus, more does NOT translate into more protection.
Only so much is utilized. We dont need to saturate our oil with ZDDP.
What about no zinc oils???
As you know most aircraft piston engines are air-cooled, so they tend
to run hot and due to this, they require the use of an ashless oil.
That simply means that when the oil burns, it must burn completely and
not leave any ash behind. Aircraft engines are mostly flat-tappet
engines and they will last 2000 hrs TBO (Time Before Overall) without any ZDDP...
