AMSOIL Break-In Oil is an SAE 30 viscosity grade oil
formulated without friction modifiers to allow for
quick and efficient piston ring seating in new and
rebuilt high-performance and racing engines. It
contains zinc and phosphorus anti-wear additives to
protect cam lobes, lifters and rockers during the
critical break-in period when wear rates are
highest, while its increased film strength protects
rod and main bearings from damage. AMSOIL Break-In
Oil is designed to increase compression, horsepower
and torque for maximum engine performance.
Quickly Seats Rings
The primary goal during engine break-in is to seat
the rings against the cylinder wall. Properly seated
rings increase compression, resulting in maximum
horsepower; they reduce oil consumption and prevent
hot combustion gases from entering the crankcase. To
achieve this, however, the oil must allow the
correct level of “controlled wear” to occur between
the cylinder wall/ring interface while maintaining
wear protection on other critical engine parts.
Insufficient break-in leaves behind peaks on the
cylinder wall that prevent the rings from seating.
The deeper valleys, meanwhile, allow excess oil to
collect and burn during combustion, increasing oil
consumption. Too much wear results in cylinder
glazing due to peaks “rolling over” into the valleys
and preventing oil from collecting and adequately
lubricating the cylinder wall.
AMSOIL Break-In Oil’s friction-modifier-free
formula allows the sharp peaks on newly honed
cylinder walls (fig. 1) to partially flatten. The
result produces more surface area for rings to seat
against, allowing formation of a dynamic seal that
increases compression, horsepower and torque (fig.
2).

Protects Critical Parts from Wear
New flat-tappet camshafts and lifters are not
seasoned or broken in and must be heat-cycled to
achieve proper hardness. During the break-in period,
these components are susceptible to accelerated wear
because they are splash-lubricated, unlike other
areas of the engine that are pressure lubricated.
AMSOIL Break-In Oil contains high levels of zinc and
phosphorus (ZDDP) additives designed to provide the
anti-wear protection required during this critical
period.
Increased Film Strength
High-performance and racing engines often use
aftermarket parts designed to increase torque and
horsepower. The added stress can rupture the oil
film responsible for preventing harmful
metal-to-metal contact on rod and main bearings. The
base oils in AMSOIL Break-In Oil provide increased
film strength to protect bearings from wear.
APPLICATIONS
AMSOIL Break-In Oil is designed to effectively break
in high-performance and racing engines requiring SAE
30 oil, helping maximize compression, horsepower and
torque.
RECOMMENDATIONS
The engine builder’s or manufacturer’s break-in
recommendations should be followed if available.
Break-in period should not exceed 1,000 miles. When
the rings fail to seat, the exhaust ports will have
a large area of oil residue (Fig. 3). As the rings
begin this process, less oil is passed and the oil
residue area begins to shrink (Fig. 4). When the
rings are fully seated and have formed a tight seal
against the cylinder walls, no oil residue will be
evident. Other common methods to determine if rings
have seated include performing a leak-down test or
horsepower measurements over time. Break-in duration
will vary between engines. Afterwards, drain and
fill the engine with an AMSOIL high-performance
synthetic oil that meets builder or manufacturer
specifications.
HEALTH & SAFETY
This product is not expected to cause health
concerns when used for the intended application and
according to the recommendations in the Material
Safety Data Sheet (MSDS). MSDS’s are available upon
request at 715-392-7101 Keep Out of Reach of
Children. Don’t pollute. Return used oil to
collection centers.