Have any of you done any reading or heard about the content of zinc and/or phosphorous in motor oil?
Common motor oils that are intended for passenger care usage have been reformulated in the last few years. The levels of zinc have been reduced drastically. Zinc is an important additive for flat tappet camshaft engines. It provides the needed lubrication in high pressure areas such as the lifter & cam lobe contact area.
Most newer passenger car engines have roller cams these days & are not as dependant upon zinc. I believe zinc may cause problems with O2 sensors & possibly the cat cans.
Motor oils that are intended for use in diesel engines have not had the levels of zinc reduced as drastically. They still have much less zinc than previously, but the last I heard they still have enough to protect flat tappet cams. The two brands with the highest levels were Rotella & Delo. I have been using Delo 400 for several years in my Dodge/Cummins & have started using it in almost all my engines, especially during break in.
There are several zinc additives available in the aftermarket. General Motors used to sell a product known as "EOS" that was an excellent break in additive. I believe it may have been used as an assembly lube also. I don't know if it is still available. Competition Cams offers a zinc additive along with this company.
ZDDPlus™ - ZDDP Additive for Classic Cars - Agricultural Equipment & More
The important issues during new engine break in are:
To insure the piston rings mate to the cylinder walls to insure the best seal possible.
To insure that the camshaft lobes & lifters mate to each other & work harden without flattening the lobes in the process.
Of course you want to make sure that all bearing surfaces have sufficient lubrication during the first few moments of operation to prevent scoring.
Now you must remember that all these freshly machined parts inside your engine will have thousands of sharp edges, tooling marks, etc. Hopefully your engine was built with acceptable tolerances/clearances & most likely may be a bit on the 'tight side'. What this means, is that when you start this collection of new parts. A lot of rough & tight surfaces will be meeting each other for the first time. Thousands of tiny metallic pieces will be broken off as parts wear in to each other & eventually become smooth. These metallic pieces will be floating around in your oil, while being circulated through your engine & possibly scratching areas that should not be scratched. With tolerances on the tight side, the engine will also be producing more heat than usual & could possibly over-heat.
My thoughts on breaking in an engine is to use a high quality oil with a zinc additive to protect the cam. Usually I will use a single weight oil that is lighter than usual.(Unless I'm using Delo 400) I do not believe in using a synthetic oil during break in. I have read that it is to slippery. (There are break in procedures specifically for synthetics that usually involve dyno loading the engine)
I also use the freshest premium gas that I can. I like to add a bit of Marvel Mystery Oil to the fuel for the sake of the valves.
A good spark plug & determine that timing is as correct as you can get it. Timing retard will cause a lot of heat.
Supply of cooling air such as cool outside air, a box fan, etc.
When you have double checked everything... Fire her up!
In an automobile application. An engine with a flat tappet camshaft is usually brought up to the 2500 RPM range & the RPM is varied about 500 RPM above & below that range for at least 20 minutes or so. A lot of times the engine will begin to get too hot to continue & will need to be shut down & allowed to cool. Then restart & hit 2500 RPM again. This is to insure that plenty of oil is splashed onto the camshaft. After 20 to 30 minutes of run time. Shut it down & immediately drain the hot oil & remove the oil filter. You want to try to get as many of those tiny metal particles out of there as you can, before they settle out.
After the engine cools enough to work on it & all the oil has drained out. Refill the crank case with more oil & zinc additive. Inspect engine for any leaks, problems, etc. If all is well... Now we drive. I do not believe in beating the snot out of the engine. I also do not believe in babying it either. I avoid operating the engine at a steady state. I like to run it up the RPM range to about half & then let off several times. It's nice to have a nice long hill nearby. Run it up the hill easy, but more importantly... coast down the hill with no throttle. This will create vacuum that will help seat the rings.
I operate the engine as described above for about 500 miles or so. I change the oil at least once more around that 500 mile mark. After 500 to 1k miles, I figure I can start to hammer down. I do believe in high quality oils & frequent changes.
Now obviously a $99 to $150 clone may not require as extensive of a break in as a V-8 that has at least $5k in it, but it can't hurt.
I read an article on how a performance shop breaks in a Briggs engine that they intended to build for a racing class that required that the valve seat angles not be modified. Unfortunately I am unable to locate the article at this time. If anyone else knows of this article, please post a link to it. Before starting the engine. This shop would install new valve guides that had a much tighter spec than OEM Briggs. Then they would reassemble the engine & run a tank of fuel through it at a certain throttle setting for 20 minutes at a time while allowing it to cool between runs. This would heat cycle the engine. After this procedure, they would then tear it down & perform all their trick performance modifications.
Below are some links to a few interesting sites if you want to learn more about the subject.
Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power
Bob Is The Oil Guy
Engine Oiling Tips from the Pros - Tips & Tricks - Circle Track Magazine
