S54 Break in + Tuning

[enjoy_m3]

Just my .02 cents. I would follow BBR's recommendation. I rebuilt my motor with JE pistons, WPC treated rotating assembly. I wasn't sure either so I did the BMW recommended easy driving. I'm now dealing with oil consumption. I even used driven break in oil. I can't 100% confirm yet if it's the break-in procedure that caused the oil consumption. I'm hoping to confirm when I take the motor apart. It seems to smoke out of the exhaust (maybe when it burns oil the most) under heavy loads. The car runs fine without issues other than oil consumption and reduced MPG. But since I have to tear it apart and re-ring it. I will do BBR's recommendation.

thegenius, I think the 1500 idle would benefit you since you want the oil to flow to the head quickly as it breaks-in. Varying the loads is for the piston rings to set properly so you likely may not need to do it since your bottom end isn't touched.

[Chanman1029]

I did my break in about a month ago. I did 1200 miles with Driven 15W-50 BR conventional break in oil. You will need to use a total of about 7.5 quarts to fill all the empty voids in the motor and the oil cooler. I did not exceed 4k rpm, and was relatively easy on the motor for the first 200-300 miles, then I progressively gave the car occasional throttle to increase load, but never did I push it past probably 75% throttle.

[Syfon]

What do you all recommend for a built head and new cams and followers in terms of break in oil and procedure? Bottom end is original but in incredible shape so this was just a complete top end rebuild with everything brand new.

Was planning to run a break in oil from my shop (which I think is like 5w-30 equivalent?) for 100 miles then change the oil and change it one more time at 500 miles before tuning on the dyno.

Since I’m not seating rings, my machinist said just take it easy (4k rpm and under ) for 500 miles and DO NOT idle. Sound about right?

Nothing. Fill it with 10w-60 and send it. Head doesn't require break in. Our cams do not require break in either.

I mean don't redline it straight away. Take it relatively easy for the first few hundred km but don't be shy either.

[Syfon]

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Just my .02 cents. I would follow BBR's recommendation. I rebuilt my motor with JE pistons, WPC treated rotating assembly. I wasn't sure either so I did the BMW recommended easy driving. I'm now dealing with oil consumption. I even used driven break in oil. I can't 100% confirm yet if it's the break-in procedure that caused the oil consumption. I'm hoping to confirm when I take the motor apart. It seems to smoke out of the exhaust (maybe when it burns oil the most) under heavy loads. The car runs fine without issues other than oil consumption and reduced MPG. But since I have to tear it apart and re-ring it. I will do BBR's recommendation.

thegenius, I think the 1500 idle would benefit you since you want the oil to flow to the head quickly as it breaks-in. Varying the loads is for the piston rings to set properly so you likely may not need to do it since your bottom end isn't touched.

Oil consumption right after a fresh motor build is due to one thing and one thing only (assuming the motor has been correctly assembled) - the cylinder bores have been glazed therefore not allowing the piston rings to seat, oil to blow by and be burnt.

My guess is you'll find the cylinder bores are glazed.

My $0.02 - when I ran in my s54 (refreshed bottom-end with new rings, refreshed head with cams, etc.), I took it relatively easy for the first ~150km before I began loading up the motor in 3rd & 4th gears by driving up hills numerous times. By placing the motor under relatively heavy load (no more than ~75% throttle), it forces the compression and oil control rings to expand and "seat" against the freshly honed bores. This in turn allows the motor to achieve the correct compression and not burn any oil during the combustion process.

After ~750km of relatively easy driving, I swapped out the oil for LM 10w-60 and sent it. Started driving her hard.

I'm now ~5,000km post-rebuild, tuned to 332whp and my S54 does not burn a single drop of oil.

[Thoglan]

Another data point to add. I'm at 10,000km post rebuild with zero oil consumption. I did not use a break in oil as recommended by my engine builder (builds a lot of BMW and S54 racecars) and used 10w60 from the first start up. Break-in procedure was essentially 500km of moderately hard driving then good to go. It seems there is more than one way to break in the motors properly and none of it very scientific.

[Slideways]

Is there any information out there that the factory BMW engines had a special break-in procedure before being installed in the car and delivered to dealerships? The only procedure I am aware of is the 1200mi break-in procedure the first owner had to follow using regular 10W60. Other than that, my guess is the car had a few short stints around the production line and a short dyno test as seen in this video:

The factory built S54 hardly burns any oil, so why not follow the factory break-in procedure exactly on 10W60 oil to achieve the same result on a rebuilt engine?