Guys, I'm taking delivery of my Red S2K this Saturday (Finally!). I live 350 miles from this dealer in Michigan and I will drive it all the way back home in Louisville, Kentucky (lots of twisty country roads around here, but that will be after the car is ready).

I need advice in what is the REAL proper way to breake a car in. I have several versions.
-Keeping the RPMs steady at constant speed is the best way.
-Moving up and down the RPM range but below 5500 RPM is the best way.
-Either of the above but don't drive it for more than 150 miles at a time is the best way.
-Either of the first two, non-stop until you reach 1000 miles is the best way(to avoid the dilatation-contraction of the material due to the temperature changes that you get with frequent stops to cool down the car) .

In conclusion, I am even more confused than ever. Any experts around here? Any evidence-based opinions?

2 Days for Delivery!

 

This is the one you want. Vary the RPMs, stay below 5500, and try not to use cruise control!

 

I got the real scoop from an powertrain engineer... you want to vary the load and the RPM. Initially, in the first few miles you want to use high-load. Keeping the RPM under 5000, use heavy throttle applications. Not floored, but put the engine under good load. That takes allot of material off the cylinder walls...

Then, after maybe 30 miles of varying a heavy load, start using light loads and less variation of RPM (you always want to vary rpm) This will allow the rings to push the material that came off the walls down into the sump to be filtered. Then you alternate high load, low load as you continue to break in.

Also, many heat cycles are good. Letting things expand and contract will allow the engine to seat under all conditions. If you drive 1000 miles from the dealer without turning the car off, it's not broken-in. The parts need to seat at all temperatures.

Our second engine got 400 miles less than 5k, then up to 600 mlies under 6k, and then up to 1000 miles under 7.5k. All the while I varied the load and RPM, and gave the car no less than 100 heat-cycles (cool off, warm up cycles)

This was advice from and engineer, who I trust very much. HTH!

 

Both answer's are correct but Jason's is the "better answer"...remember that from tests in school? More then one answer may be correct...but you are to select the "Best Answer"...which is Jason's.

Utah S2K
Aerospace Engineer

 

I recommend a plastic wedge, a wire hanger and a long screwdriver. j/k

 

Jason's answer is the only correct answer.

It is good enough that I'm printing it out and taping it to my dash as I advance the break-in from the 85 current miles on my new short stock to that 1000 mile mark.

Jason, what do you and the power train engineer recommend on oil: how long to leave the first oil in, when to change to synthetic oil, what if any additives to use. Did you use a moly additive in your new short block?

Barry in Wyoming

 

That is exactly what i did. I even wrote it in my Palm just in case.

Thanks Jason Saini. All my respect for you, Professor.
Tomorrow will do as told.

One day for Delivery!!