Do you care to elaborate on why excessive idling is to be avoided?
Initial Startup Procedure:
It is imperative that the engine’s initial startup happen quickly to ensure proper break-in.
· NOTE: For proper camshaft and tappet break-in, specific recommendations from the camshaft
manufacturer will supersede the following Startup Procedure.
· If the engine is properly assembled and installed (in vehicle, test stand or dyno) the engine should
start after only a few revolutions. If the engine does not start, double check ignition and fuel settings.
· Once started, verify proper oil pressure and continuously monitor during break-in cycle.
· As soon as the engine starts, increase and hold the rpm between approximately 25-35% of maximum
engine rpm while verifying the following:
§ EXAMPLE: maximum engine rpm of 8000rpm would hold between 2000-2800rpm
o Ensure all cylinders are firing.
o Verify and adjust for proper timing and fuel as soon as possible.
§ Excessive fuel can wash the oil from cylinders and prohibit break-in, leading to
cylinder glazing.
· Once all timing, fueling and other parameters are verified correct, run the engine for approximately
15-30 minutes.
o Vary the RPM between 25-35% of the maximum engine rpm for the duration of the break-in.
§ Allowing the engine to idle should be avoided if at all possible.
o Listen for any unusual noises, shut down if necessary.
o Allow the engine to reach full operating temperature, but shut down to investigate if
exceeding normal operating temps.
o In nearly all instances, it is best to shut down immediately if an issue is found and make
adjustments as necessary.
· Initial startup procedure can be repeated as needed but caution should be taken as excessively
running a new engine unloaded can lead to insufficient ring seating and poor performance. It is best
to place the engine under a mild load as soon as possible after the initial startup procedure is
complete.
o A note concerning engine run stands: They should only be used to ensure no leaks, adjust
timing and fuel or break-in flat tappet camshafts. An unloaded run stand WILL NOT properly
seat the rings.
o Change oil and filter from break-in to recommended conventional oil.
Engine Break-in:
Recommended Procedures
Version 00
MAHLE Motorsport, Fletcher, IM07 Page 3 of 3
Property of MAHLE Inc. Utilization only for the assigned purpose. Disclosure to third parties only with written permission.
Running Procedure:
Once all checks are performed and the engine has no issues detected, the engine should be ran under a load
to properly seat the rings. Loading the engine increases the cylinder pressure and forces the rings into the
bore to help the seating process.
· In Vehicle:
o NOTE: Ensure brakes, steering and suspension all function properly before starting in-vehicle
running procedure.
o Using part throttle, apply varying loads and rpm. Avoid using heavy throttle / acceleration and
high rpm.
§ Street Vehicle:
· This should be accomplished over a short 20-30 min drive.
§ Race Vehicle:
· This should be accomplished over the first practice session.
o Next, start at 25% of the max rpm with light throttle and accelerate at wide open throttle to
75% of max rpm. Then engine brake with the throttle closed, back to 25% max rpm. Repeat
this 5-6 times.
§ Example: 8000rpm max would start at 2000rpm and accelerate to 6000rpm then
engine brake back to 2000rpm.
· On Dyno:
o Follow dyno recommended break-in procedure if available.
o Part throttle load to 75% max rpm and observe crankcase pressure.
o Keep applying higher loads and increase RPM in approximately 1000 rpm increments with
subsequent pulls until max rpm and load is reached.
o Once crankcase pressure has stabilized and is repeatable, the rings are seated.
· Double check to ensure no issues have arisen and change oil and filter again.
· Run as engine build was intended.
(I wish I had a workspace.)
