Hi guys,

Engine is back in the car ready to fire up and start driving.
Installed new OEM piston rings.

Any recommendations for break in of the new rings?
Mineral oil and the normal accel / engine break pattern?
Or anything special to consider since this is untouched nikasil cylinders?

 

Run the hell out of hell out of the engine to seat rings. Do not baby it. That's what Porsche does as the new engines are put on the dyno right away.

When I had my engine fully rebuilt, we filled it with 0W40, started it and let it run and fully warm up on the lift while checking for any leaks. After that, we shut it down and did an oil and filter change to flush out all the sealants and crap from the engine. We then filled it with 5W50 and took the car for an initial 15 minute run doing successive pulls at increasing boost in 3rd gear. 3rd or 4th pull was at full and sustained boost to redline. We then put the car back on the lift to check for any leaks.

After that the initial break in is complete. I then put 400 miles on the car over the next couple of weekends just running on the street with varied use of anything from stop and go to full throttle runs. I avoided constant throttle highway use. After this the car was taken to the track and run all out since.. Engine runs perfect and oil consumption is near zero.

 

Thanks John,

Are those mineral oils that you use for the first couple of oil fills?

 

The first oil change will have some of the loctite case sealant in the oil filter. It scared me the first time I looked at it, took me a few seconds to realize what it was.

 

No sir. Just Mobil 1 synthetic. I wouldn't overthink this too much. Run the engine hard...

 

Not mineral oil. Not for the Porsche. I was taught to break in the engine using the same oil the engine would run normally.

Just follow what pwdrhound offered. Avoid high RPMs (4K or more) for a while but do once the engine is up to temperature use some throttle.

The idea is to vary the pressure in the cylinders to vary the force at which the rings are pressed against the cylinder walls and the ring lands in the piston. These interfaces need some pressure to help them develop a long and trouble free "sealing surface".

But too high of RPMs can given the higher friction new rings have can result in damage to the ring (breakage) or damage to the cylinder walls (scoring).

 

Here we go, the debate begins again. Nice easy break in VS drive it like you stole it break in.

 

Show me a race car that gets driven easily to break in the motor...

 

+1's, allow to get up to temp and load it up, also make sure to do lots of engine 'braking'/decel

 

Engine brake from high rpm as much as possible... when I used to race motorcycles would typically run it up to 2/3 of redline in first at half throttle and engine brake down, 2nd gear do a little more rpm and a little more throttle, 3rd gear little more, and 4th gear should run it up to max rpm and let it engine brake down. After that, change the oil again and you're ready to go. Don't hold same rpm and same throttle position for extended periods. You want to build a lot of cylinder pressure. Best way to do it is on track or on dyno.

 

Big difference. I've come across race engines with nearly a mirror finish to the cylinder walls. The engine is intended to use a very light oil - to reduce friction losses. There is essentially no break in the engine is ready to race *now*.

The general rule of break in is an engine that is broken in aggressively will make max power sooner but the engine's output falls off quicker too. For a race engine an aggressive break in makes sense as one wants the engine to make its max power sooner say at the start of the race or racing season rather than into the race or season.

An engine that is broken in less aggressively takes longer to develop max power but once it reaches this point continues to deliver this power level longer before it starts to fall off. Just what one wants for a street engine.

 

This is not advised. Engine braking from high RPMSs has the rings unsupported by compression/combustion pressure. The rings rattle around in the ring grooves and rock slightly and develop a rounded face which doesn't seal as well.

I was always told to whenever possible avoid engine braking from an elevated RPM level. "4000" was the threshold I recall.

 

I'd like to some actual evidence rather than anecdotal commentary to prove this, especially considering how Porsche runs the engines hard before they ever leave the factory.

My personal anecdotal experience is that I broke in a street engine in a car the same way we did break in on race bikes and it made more power than others and didn't have the oil consumption issues that other vehicles of the same model/same engine had (Corvette Z06). I kept the car until it had over 50k miles and a buddy bought it- it's still running strong with no issues and approaching 90k miles last I heard, which was a year or 2 ago. We would run the race bikes for a season or 2 and then convert back to street trim and sell them, I kept one of those for a few years and had no problems regarding power loss or reliability as well.

 

Wow.... If you have pistons rings rattling around, you have way more problems to worry about than how to break in your engine You have been told things, where as I have personal experience..

 

there isn't a universal max break-in RPM for engine...it's a lot about piston speeds...(reason for over square)