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Everything You Need to Know About Engine Break In Oils

Best Break In Oil 1Oil is the blood that keeps an engine alive, this sacred fluid lubricates, cools, cleans and prevents wear. If oil changes are not carried out at the required intervals, metal, dirt, soot and other particles can build up in your oil, (a lot of this is too small to be caught in the filter) also it is these particles that cause oil to become abrasive which as you can imagine, will dramatically catalyze engine wear. This article will tell you about the best break in oils available, but first inform you of the purpose and mechanics behind the oil itself.

It’s not just changing oil that is important, it is also imperative to use a good quality break in oil when buying or building a new engine. This oil is designed to aid your engine during the break in period to ensure everything runs nice and smoothly. However, in the past five years or so, the Environmental Protection Agency has changed its regulations on oil and banned numerous anti wear components from the production of the engine oil. Therefore, it is a necessity to get yourself a decent break in oil that falls within the parameters set out by the authorities while still giving you effective anti - wear components.

Today’s engines have a good standard delivery system to properly lubricate all the components of the engine except for one…the camshaft. The oils capability of reaching the top third of the engine has been described as ‘limited’ at best. The use of a windage tray, or the modification of rod side clearances to prevent oil splash, actually reduces the amount of oil reaching the camshaft. The use of custom oil pans do not help the cause either. Buying durable parts is all good and well, but are you giving enough thought to the quality of oil you're planning to use during the break in period?

Break in oils have been used for many years by both OEMs and enthusiasts alike. In fact, there is a chapter on break in oils in the “SAE Lubricants Handbook”. Up until a few years ago, OEM’s would usually use break in oils before the car would roll off the assembly line. However, Environmental Protection Agency tightened their noose around fuel economy requirements and pushed for a reduction in additives within break in oils. This, unfortunately was end of break in oils being used as factory fills for new vehicles.

The good news is break in oil made a come back due to the development of cleaner detergent additives as part of the APISM oil specifications in 2005. Joe Gibbs Driven aka Driven Racing Oil was the first to bring out a break in oil aimed at solving the flat tappet camshaft break in issues associated with the new spec of oils.

Protecting the Camshaft

During this period, Joe Gibbs Racing’s engine store was experimenting with their own custom blended oil as they were also having flat tappet break in issues. Eventually they stumbled upon a solution giving birth to the first high zinc, low detergent petroleum break in oil.

The method used to create break in oil is building from the ground up, one compound at a time. Maxima Racing Oil’s Mike Marcella says that a lot of the surface active chemistries that would usually be seen in your typical racing oil are either reduced or removed in a break in oil. “This prevents unnecessary competition between the chemistries you want on the surface (anti-wear chemistries), and the chemistries you don’t want (friction modifiers, detergents, dispersants).”

Surprisingly, throwing a load of anti wear chemistry at it doesn’t really help either. “A certain amount of wear must be allowed for proper break-in to occur,” sates Marcella. “So, if huge amounts of ZDDP are used in a break-in oil, too large of an anti-wear film can be formed, actually preventing removal of surface asperities and delaying break-in. Further, the unnecessarily large films of excessive ZDDP can hinder power, creating a situation that is not ideal for a high-performance engine.”

Marcella explains that Maxima’s break in oils will give a faster ring seating and an increase in power output by balancing the chemistry. “By using the proper anti-wear chemistries in the correct amount and balancing them with the rest of the formulation, we can achieve more power and a quicker ring sealing.”

Break In Vs. Race Oils

Driven Racing Oil’s Lake Speed Jr., claims that break in oils and race oils are two very different things when you look into the chemistry, this is because they are intended for two very different purposes. “While the race oil is designed to reduce wear and increase horsepower, the job of the break-in oil is to allow a controlled amount of wear. As such, race oils are loaded with friction modifiers and other components that reduce friction. On the other hand, break-in oils don’t contain friction reducers. Piston rings are especially sensitive to low friction oils during break-in. For these reasons, break-in oils are typically petroleum-based (non-synthetic) and don’t contain friction modifiers.”

Due to the fact break in oils are made with the intention of protecting the camshaft and valve-train parts during the engines infancy, they will usually contain increased amounts of ZDDP. The ZDDP found in the break in oils aim to prevent the scuffing of the flat-tappet cams and galling of push rod tips during the break in. A break in oil consisting of the correct formula actually wont need any additional ZDDP or other additives for the break in. In all fairness, an overload of ZDDP will actually heighten the chance of camshaft and valve-train wear. The perfect balance in chemistry is imperative, so it's wise to stay away from the “more is better” mind set.

If you want to get technical, break in oils contain on average double the amount of secondary ZDDP, which is the most active type of the compound. (there’s a lot of ZDDP types). Moreover, break in oils are normally low in detergent. This is due to the fact that lower detergent levels allows the secondary ZDDP to have more of an impact. As opposed to shelf diesel oils which are high in detergent, break in oils reduce break in wear by around 30% as well as improving ring seal.

Some formulas as seen in your regular race oil will actually slow down or completely halt the break in process. Marcella states “Most race-specific oils have ZDDP levels that are too high to allow the removal of surface asperities required for proper break-in and also contain higher levels of other surface-active chemistries that will also prevent removal of said asperities.”

As mentioned before, chemistry is the root to success when your talking break in oils, it is this chemistry that allows the smoothing of the load bearing parts in the engine. Smoother Surfaces can hold more weight, prove less material fatigue and reduce friction, Speed claims that “By reducing valve train wear during initial break-in, overall engine wear is reduced. Because oil filters never remove 100% of the contaminants in the oil, the wear debris from the valve-train (especially from flat tappet cams) causes abrasive wear in other parts of the engine. Used oil analysis has proven that lower iron wear metals (typically valve-train) during break-in reduces aluminum, copper, tin and lead (from pistons, bushings and bearings). The bottom line is that all engines benefit from break-in oil, not just flat tappet camshaft engines.”

All this begs the question of how long should you leave your break in oil in for? It is  recommend for a gasoline powered race engine that a 20-minute initial break-in at 2,800 rpm with 10% applied load is followed. Secondarily, swap the oil filter and top off the oil level. When the engine is nice and warmed up, start making sweep tests and steadily bring up the peak rpm of the sweep until the engine has hit full rpm several times. As soon as the power level plateaus from test to test, cease the engine and drain the break-in oil. The engine is now primed for the race oil.

Marcella explains how his company doesn't advise professional engine builders on how to break in their engines. He says that its each their own and everyone will have their preference regarding the process and how to get more performance out of their engines. “It is really up to the user and what they’re comfortable with based on their experience. Truly, once the compression targets are met and the engine builder deems the engine appropriately broken in, the oil can be changed for a regular race oil. Having said that, many users of Maxima's break-in oil will continue using the oil as a regular oil. We don't recommend this and prefer users switch to a regular race oil however if the user is getting good performance, it’d be hard to argue with those results.”

One of the most important functions of motor oil is to remove the heat from a sliding "metal on metal" surface. The oil will cool as it travels through the bearing taking away the heat caused by friction just like air flowing around a cylinder head. However, during a break in, you must allow some friction to take place in order for the camshaft and rings to seat properly.

Diesel Break In Oil Procedure

John Martin, a chemist said how when he used to work at Lubrizol, they found a solution to an issue Mercedes was having with one of their diesel engines not breaking in quickly enough. He mentioned how that in the early 80’s Daimler – Benz was utilizing an engine oil high in TBN as their factory fill in all their engines to allow oil change intervals up to 62,000 miles. However, this came back to bite them as the engines were burning excessive amounts of oil and their customers were in need of rebuilds before their warranties had run out.

Cummins 6BT (5.9 L) 210 HP Diesel Engine

What Martin and Lubrizol found out was that the high levels of TBN in the diesel oil was preventing sufficient ring wear to break in the cylinders. The harder piston rings, combined with the cast alloyed cylinder liners plus the diesel oil, had in fact prevented any wear thus, the engines were not breaking in fully until the 50,000 mile mark. They discovered that the majority of wear in the piston ring/cylinder wall was due to chemical corrosion, and not a shortage of wear protection. Following that they formulated a break in oil that consisted of lower levels of detergent with enough ZDDP levels to aid the valve-train components, therefore solving the problem.

So your average regular oil that consists of detergents and additives in order to prevent friction will mean the piston rings and cylinder walls wont wear quickly enough to seal properly, equating to more blowby and cylinder leakage. Good break in oils can aid this process by speeding things up a lot better than fully formulated automotive or racing engine oils. This fact has been proved time and time again over the years from the OEMs to NASCAR, and according to the experts, the results will re-enforce this compared to your run of the mill gas or diesel engine oils.

However, if you find yourself reading this thinking its different from what you read previously when researching break in regimens, that is because over time they have changed. But why? For a lot of engines, the time it takes for a full break in to occur had decreased significantly from a number of days/months, to a couple hours for a few reasons. The main reason being that the factories where these are produced are now a lot more proficient when it comes to machining and assembly. To give an example, it is a lot easier to hold tighter tolerances now, and the average surface finish of a brand new cylinder wall is a lot better than in the past.

A few decades ago manufacturers were capable of producing high grade tolerances with however it was generally not cost effective and not easily mass produced. In essence, this means that your standard engine of today in some respect is equivalent to a top of the line unit back then. Design has also changed and a lot of engines use roller lifters instead of flat lifters.

The other reason for the now shorter break in periods is that more science has been put to use when understanding break in, this in turn led to the realization that some of the much longer break in requirements were based on less than credible reasoning. However, newer isn't necessarily better. New EPA compliant engines now have DPF, EGR emissions abatement systems that need additional lubrication and are prone to additional break in measures.

Our Break In Procedure at Big Bear Engine Company

With every engine that leaves our shop we attach a break-in card in addition to sending out break-in instructions. Improper break in will ruin a diesel engine pretty quickly and sadly we have seen some very good customers end up making some poor choices thus ruining their brand new engines. The two golden rules you must remember when you get a new diesel engine is to never let the engine idle for extended periods of time and to use a standard mineral diesel oil vs. a synthetic oil.

You never want to let an industrial diesel engine idle for extended periods of time, the reason for this is wash down of the cylinder and lack of lubrication. Idling can also lead to lack of compression and allow exhaust gas to seep through the rings causing wear. Most new diesel engines are turbocharged, that being said, a turbo generates a lot of heat even when the engine is shut off. At idle the turbo is still generating heat but no longer being cooled properly by the air, water or lubricating oil. In addition to turbos, modern diesel engines have DPF (Diesel Particulate Filters) and EGR Coolers (Exhaust Gas Recirculating. See Above) systems that do not function properly at idle speeds. It a good way to get regeneration issues and clog up the turbo with soot.

Diesel Break In Oil Shell Rotella 15W-40 Diesel Engine Oil

Recommended Diesel Break In Oil - Shell Rotella 15W-40 Diesel Engine Oil

Secondly, you want to use a standard diesel oil instead of a synthetic for the break in period. Our break in period is roughly 5,500 miles. Synthetic oil's lubricity is thinner than standard oil and will not allow the rings and gaskets to seat properly. If you use a synthetic the rings won't seat properly and you'll burn oil and will never get full compression. We recommend using Shell Rotella T4 15W-40 as a very well rounded mineral diesel oil. During the first year of operation the engine's internal components will expand and contract multiple times while reaching it final structural tolerances. After that first oil change you can then use a synthetic oil if you choose. Once you get your new engine from us we recommend that you put in under a normal load and get it going. Try not to let the engine idle for extended periods, hard shift or accelerate quickly for the first 5,500 miles or push the engine outside of normal load conditions. Keep an eye on your temperature gauges and be smart about not letting the engine overheat.

Our Full Break-In Instructions for New or Reman Diesel Engines:

All engines, used, new or reman, need to be broken in properly to ensure optimum performance. The break-in procedure allows engine parts from different machined surfaces to conform to each other and form a tighter seal.

To properly break-in your new or reman engine, please follow the below procedures. Failure to do so can impact the quality and life of your engine, and can void the warranty.

1. Your new or reman engine is specific to your original engine serial number, however applications may vary. Please verify all freeze plugs are in place prior to installation.
2. PRE LUBE engine prior to start up.
3. Do not use synthetic oil.
4. On initial start up the engine should be run for only 5-10 minutes; the length of time to determine the engine has no leaks and parts are torqued properly.
5. The engine should be placed under moderate to heavy load immediately at variable RPM for the first 200 miles or 3-4 hours. Revving the engine on a stationary truck will NOT build load pressure required for break-in.
6. After break-in It is recommended to drain oil, install new filters and fill with new oil.

As discussed, never allow your engine to idle for an extended period of time during break-in. A new or reman engine left to idle or operate under low or no load conditions will contribute to glazed cylinders. When this happens the rings will not properly seat and will contribute to oil consumption, low engine power, and decreased fuel economy. The remedy for correction will be to replace cylinder liners and rings. Additionally, all other components/parts/systems that complete a long block during installation should be thoroughly inspected, cleaned, and be deemed suitable for use so the long block engine is not adversely impacted.

Concluding Thoughts

In the past, both engineers and enthusiasts alike had developed and deep theories on what was required and why, and it was somewhat tricky to apply any empirical evidence when trying to determine the accuracy of said theories. Whereas today, engineers can advise with confidence not to put too much trust into old theories. You will always have some people that will disregard new procedures weather they are proven or not as they are adamant in their ways. These strong beliefs will serve just like a placebo, allowing them to confidently believe that they are getting the best from their engine.

Some manufacturers have gone to the extent of removing break in procedures all together as mechanically some think they are no longer useful. Other manufacturers will name procedures users should stay away from to avoid complaints from customers claiming the manual was incomplete. At the end of the day, it is the responsibility of the mechanic or end user to ensure the correct installation of engine.

Source: Carley, Larry. “Break-In Oils and Assembly Lube Needs.” Engine Builder Magazine, 24 Oct. 2014

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