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.
“We get a lot of feedback on the AMSOIL break-in oil and I sell quite a bit here in the store. I to have used it in an air cooled Corvair with great results. In about 200 miles all issues with the fresh engine were solved. Even the price is just right!”
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.
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 engine is new, the exhaust ports will have a large area of oil residue (Fig. 3). As the rings begin to seat, 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.
Break-in oil is different from regular motor oil because, by design, it is supposed to allow the rings to wear down the peaks on the cylinder wall to form a good seal. Regular motor oil, in contrast, is designed to prevent wear.
Camshaft break in
Flat-tappet cams can wear out faster than their roller-cam cousins, especially in engines modified with high-tension valve springs. Worn lobes or tappets affect valve lift and duration, which reduces engine power and efficiency.
In extreme cases, increased pressure can remove material from the lobes and deposit it in the oil, where it circulates through the engine and causes damage. Using break-in oil helps harden the camshaft so it’s more resilient to wear.
As a rule of thumb, a good break-in oil should contain at least 1,000 ppm ZDDP. At AMSOIL, we take it a few steps further; our Break-In Oil contains 2,200 ppm zinc and 2,000 ppm phosphorus.
Break In Oil Product Reviews
Highly Trusted Brand
By DDM, a Verified Buyer from Cocoa, Florida on April 16, 2025
Purchased a new Generac 15.5 Kw generator for our hurricanes. Knowing that Amsoil is the pioneer of API rated synthetic motor oil, it was a no-brainer to go with their Break-In Oil to start protecting my valuable asset from the start. I plan on moving to the Amsoil Small Engine Oil after the break-in time has been met per Generac specs. Looking forward to a long reliable enginge life to support my emergency needs if required.
100% happy
By ACEY, a Verified Buyer on June 04, 2024
So i went with the break in oil and i was not disappointed. the oil filter combo went the distance of the break in. for my Equinox this was 500 miles. zero metal flakes after the first change. the oil still had a nice red color and everything is sealed up and broke in so smooth. they got me to total seal compression. i am 100% happy as this is my first use of a complete Amsoil from New Engine day 1. i will not ever use another product again. Amsoil has a new life long customer!!!! keep it up. i am one of many who understands Amsoil is the way to Go now.
BEST BREAK IN OIL, PERIOD!
By JENSEN, a Verified Buyer from North Carolina on March 27, 2024
Look, after recently wiping out hydraulic flat tappet cam and lifter sets using parts store oil with zinc additive, I switched to Amsoil. I’ve since broke in two SBC hydraulic flat tappet engines with Amsoil. Everything broke in the way it should. I will never go back to store bought oil and additives for engine break in. This stuff works!! Don’t cheap out on your investment with cheap oil, especially when breaking them in!
Great product
By Charles, a Verified Buyer from Norwood NC on January 31, 2019
We are a military vehicle rebuild / restoration shop. We build a lot of engines, AMSOIL 30W break-in oil goes into every new engine we build.
Bottom Line
Yes, I would recommend this to a friend.
Yes
By Bill, a Verified Buyer from Wabash indiana on July 03, 2018
Engine building
Bottom Line
Yes, I would recommend this to a friend.
Highly recommend product
By Jr, a Verified Buyer from Baytown on July 02, 2018
I used the engine break in oil for my freshly build LS motor…..
Bottom Line
Yes, I would recommend this to a friend.
I am definately impressed! Great products!
By Slim, a Verified Buyer from NE on June 05, 2018
Glad they have an oil for older flat tappet cam vehicles.
Great product
By Corvairguy, a Verified Buyer from Peoria IL on April 18, 2018
I use it in every new Corvair engine.
This break in oil is great for new engines
By mr. classic, a Verified Buyer from Mobile, AL on April 11, 2018
I just had an engine rebuild on my ’62 Ford Galaxie and the mechanic put Delo 10W40 in the motor for break in. It is the nature of a rebuild job for an engine to use oil and I had added 2 qts already then it dawned on me about the break in oil so I ordered some pretty quick. There was a little smoke from synthetic oil which I expected but that happened twice, no more smoke. No more oil consumption and the rings were set pretty quick and when the car comes back from the shop, I have the Amsoil Z-Rod for classic cars waiting on it.
Definitely use every time I fire up a new engine.
By Randy, a Verified Buyer from Daleville, IN on January 29, 2018
Totally Recommend
By Hayden Huff, a Verified Buyer from Butler, PA on January 28, 2018
I rebuilt my 2013 WRX motor and used this oil as a break in oil. When I drained the fluid, it was nice and light colored enough I could see if anything was in my oil. 2500 miles on my car now and still going strong with nothing other than Amsoil products.
I will defiantly use this product again.
By Benjamin, a Verified Buyer from Yuma, AZ on November 29, 2017
Great product. No fouled plugs during break in, quick and steady power gains. 15 hours in and the oil still looks clean on the dipstick. Very pleased with product.
