New Cylinder Break In Advice

WDD

WDD

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Vintage Snazzy (so my adult children say)
I’m replacing three cylinders in a Continental 0 470R for my C182P.

From what I can gather,
- for first 50 hours use mineral oil
~ first 4 hours run constant full throttle and full RPM to set the rings
~ first 50 hours do XC and full throttle work only, no pattern work or variable throttle flying.
~ Oil consumption should stabilize at 10 hours.
- of course keep it out of red zone

For those who have done this before, any edits to what I put down? I’m assuming the mineral oil isn’t going to hurt the remaining three cylinders,

FWIW, one is a completely new cylinder, piston and ring set. The other two are what was on the engine but machine shop checked the bore, honed it, new valve guides, ground and lapped the valve seats.
 
Last edited:
WDD said:
For those who have done this before, any edits to what I put down? I’m assuming the mineral oil isn’t going to hurt the remaining three cylinders,
Click to expand...
Many threads on this found on this site.
Phillips xc20w50 may be used for break in and ongoing post break in timeframe.
 
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Also following. I've got one cylinder out for a rebuild right now. On my Ercoupe, that's 25% of what I've got
 
I stopped mineral oil as soon at 10 hours and went to regular oil
 
Do you have a CHT gauge for each cylinder? You basically need to set the rings. That will show up as a drop in CHT. On my one cylinder that got replaced, that happened on my first take off. Was running hot and all of a sudden dropped 50 degrees. I pretty much did nothing special after that. Oil consumption is about 1 qt per 10 hours now, was less than half that before. Broken rings on the one that was replaced. I'd do a bit less than what you outlined. Change oil at 10 hours and go forth and fly.
 
Here's Lycoming's oil recommendation from SI 1014N

D. All other engines must be operated on non-dispersant mineral oil during the first 50 hours of operation, oruntil oil consumption has stabilized. Use of LW-16702, while required for certain engine models as listed inPart B above, could inhibit break-in on other engine models and therefore should not be used during break-in.Reference Service Bulletin No. 446, Service Bulletin No. 471, and/or Service Instruction No. 1409 foradditional information. If an ashless dispersant oil is used in a new engine, or a newly overhauled engine, highoil consumption might possibly be experienced. The additives in some of these ashless dispersant oils mayretard the break-in of the piston rings and cylinder walls. This condition can be avoided by the use of nondispersant mineral oil until oil consumption has stabilized and then change to ashless dispersant oil. Nondispersant mineral oil must also be used following the replacement of one or more cylinders until the oilconsumption has stabilized
Click to expand...

SI 1427C specifies the break in procedure:

FIXED WING
A. PREPARATION FOR GROUND OPERATIONAL TEST WITH ENGINE INSTALLED IN
AIRCRAFT
NOTE
Refer to the latest revision of Service Instruction 1014 for the recommended oil to be used for engine
breakin on Lycoming engine models. In most cases, turbocharged engines are to use ashless
dispersant oil for breakin. Nonturbocharged engines are to use aviation grade mineral oil for breakin. Follow Service Instruction 1014 to use the correct oil for breakin.
1. Do the engine preoil in accordance with the latest revision of Service Instruction No. 1241.
2. Calibrate the cylinder head temperature gage, oil temperature gage, oil pressure gage, manifold
pressure gage, and tachometer before the ground operational test.
CAUTION
MAKE SURE THAT ALL VENT AND BREATHER LINES ARE INSTALLED CORRECTLY
AND ARE SECURELY IN PLACE IN ACCORDANCE WITH THE AIRFRAME
MAINTENANCE MANUAL.
3. Install all airframe baffles and cowling
4. For optimum cooling during the ground operational test, use a test club. If the test club is not
available, use the regular flight propeller, however, monitor the cylinder head temperature
closely. B. GROUND OPERATIONAL TEST
NOTE
Before the ground operational test, the oil cooler system must not have any air locks.
If the engine had failed before overhaul, it is possible that the oil cooler, propeller and governor
could have been contaminated. During overhaul, these parts were to either be replaced or cleaned
and examined by an approved repair facility.
1. Before the start of the ground operational test, examine the oil cooler, propeller, and governor for
metal contamination. These parts must be clean and free of contamination before the ground
operational test can begin.
2. Put the aircraft in a position facing the wind.
3. Start the engine and look at the oil pressure gage. If sufficient oil pressure indication is not
shown within 30 seconds, stop the engine. Identify and correct the cause.
4. If oil pressure is sufficient, operate the engine at 1000 RPM until the oil temperature is stable or
is at 140°F (60°C). After warmup, the oil pressure is not to be less than the minimum specified
pressure in the applicable Lycoming Operator’s Manual.
5. Increase engine speed to 1500 RPM and operate at that speed for 15 minutes.
6. Make sure the cylinder head temperature, oil temperature and oil pressure is within the specified
limits in the Lycoming Operator’s Manual. NOTE
Extended ground operation can cause excessively high cylinder and/or oil temperatures. NOTE
If any malfunction occurs, stop the engine and let it cool. Identify and correct the cause
before continuation of the ground operational test.
a. Start the engine again and monitor oil pressure.
b. Increase engine speed to 1500 RPM for 5 minutes.
7. If the engine has magnetos, measure the magneto dropoff as described in the latest revision of
Service Instruction No. 1132.
8. Do a cycle of the propeller pitch and a feathering check as applicable as per the airframe
manufacturer’s recommendations.
9. Operate the engine to fullstatic aircraft recommended power for up to 10 seconds.
10. After engine operation at full power, slowly decrease the RPM to idle and let the engine
stabilize.
11. Do a check of the idle mixture adjustment before engine shutdown.
12. Examine the engine for oil, fuel, and hydraulic fluid leaks. Identify and correct the cause of any
leaks
13. Remove the oil suction screen and the oil pressure screen or oil filter to look for any blockage or
contamination. If no blockage or contamination is found, a flight test can be done. If blockage or
contamination is found, change the oil. Remove the blockage and contamination. Refer to the
latest revision of Service Bulletin No. 480 for instructions.
C. FLIGHT TEST. WARNING
REPLACE ENGINE TEST CLUBS WITH APPROVED FLIGHT PROPELLERS BEFORE THE
FLIGHT TEST.
1. Start the engine and do a preflight runup in accordance with the applicable manufacturer’s
Pilot’s Operator’s Handbook (POH).
2. Do a full power takeoff in accordance with the POH.
3. Monitor engine RPM, fuel flow, oil pressure, oil temperature and cylinder head temperature
during takeoff.
4. As soon as possible, decrease the engine speed to climb power in accordance with the POH.
5. Do a shallow climb angle to a suitable cruise altitude.
6. Adjust the mixture per the POH.
7. At cruise altitude, decrease power to approximately 75% and continue flight for 2 hours. For the
second hour, do power settings alternating between 65% and 75% power as per the applicable
POH.
NOTE
For correct piston ring seating, in a top overhauled engine or a newly overhauled engine, operate
the aircraft at 65% to 75% cruise power until oil consumption is stable.
For a normally aspirated (nonturbocharged) engine, it will be necessary to operate at cruise
power at the lower altitudes. Density altitude in excess of 8,000 feet (2438 m) will prevent the
engine from reaching sufficient cruise power for an acceptable breakin; 5,000 feet (1524 m) is
recommended.
If oil consumption is not stable, look for oil leaks. Identify and correct the cause of the leak(s).
8. If the engine and aircraft are operating to correct specifications per the Lycoming Operator’s
Manual, increase engine power to the maximum airframer recommendations and hold for 30
minutes. CAUTION
FOR ENGINES THAT HAVE DYNAMIC COUNTERWEIGHT ASSEMBLIES, DO NOT
OPERATE AT LOW MANIFOLD PRESSURE DURING HIGH ENGINE SPEEDS
UNDER 15 IN. HG AND RAPID CHANGES IN ENGINE SPEEDS. THESE
CONDITIONS CAN CAUSE DAMAGE TO THE COUNTERWEIGHTS, ROLLERS OR
BUSHINGS, AND CAUSE DETUNING.
9. Decrease altitude at low cruise power and closely monitor the engine instruments. Do not do
long descents at low manifold pressure. Do not decrease altitude too rapidly. The engine
temperature could decrease too quickly.
CAUTION
DO NOT DO CLOSED THROTTLE DESCENTS. CLOSED THROTTLE OPERATION
DURING DESCENTS WILL CAUSE RING FLUTTER WHICH CAN CAUSE DAMAGE
TO THE CYLINDERS AND RINGS.
10. After landing and shutdown, examine the engine for oil, fuel, and hydraulic fluid leaks. Identify
and correct the cause of any leaks.
11. Calculate fuel and oil consumption and compare the limits given in the applicable Lycoming
Operator’s Manual. If the oil consumption value is above the limits in the manual, identify and
correct the cause. Do this flight test again, up to and including this step before releasing the
aircraft for service.
12. Remove the oil suction screen and the oil pressure screen or oil filter to look for any blockage or
contamination. If no blockage or contamination is found, a flight test can be done. If blockage or
contamination is found, change the oil. Remove the blockage and contamination. Refer to the
latest revision of Service Bulletin No. 480 for instructions.
13. Record compliance with this Service Instruction in the logbook.
14. Correct any problems before releasing the engine back into service
Click to expand...

I assume Continental has similar guidance.
 
WDD said:
I’m replacing three cylinders in a Continental 0 470R for my C182P.

From what I can gather,
- for first 50 hours use mineral oil
~ first 4 hours run constant full throttle and full RPM to set the rings
~ first 50 hours do XC and full throttle work only, no pattern work or variable throttle flying.
~ Oil consumption should stabilize at 10 hours.
- of course keep it out of red zone

For those who have done this before, any edits to what I put down? I’m assuming the mineral oil isn’t going to hurt the remaining three cylinders,

FWIW, one is a completely new cylinder, piston and ring set. The other two are what was on the engine but machine shop checked the bore, honed it, new valve guides, ground and lapped the valve seats.
Click to expand...
you MUST place new rings into the cylinder without the piston to measure ring gap. Many new rings have insufficient gap when new which can create problems.
 
Kiddo's Driver said:
Not full throttle, full power, or at least high power. If you climb to 7,000 feet & keep it at full throttle you are likely not making sufficient power.
Click to expand...
Full throttle I can make 23 mp at 7000’. Not enough?
 
Pick a day with smooth air so you aren't limited by maneuvering speed when you're at full throttle below 7,000 msl maximum.
 
Consult the Cruise Performance chart in the 'Performance' section of your POH - you'll reference an intersection of RPM, pressure altitude, and air temperature and it corresponds to resulting TAS, percent power, and fuel burn.
 
Yep. I see the POH has max throttle at max power rpm of 2450 at 7500’ producing 71% max power.

That should be enough to scour/ break in the rings to the cylinders.
 
Last edited:
WDD said:
For those who have done this before, any edits to what I put down?
Click to expand...
For aftermarket cylinders follow their specific instructions on break-in. For everything else follow Continental SIL 012. This route assists in maintaining any warranty claims should the need arise and greatly reduces the chances of having the cylinder not break-in properly.
 
My suggest has always been to follow the instructions of whomever
is warrantying the cylinders.

Do ALL cockpit items such as trim, frequencies etc before starting the engine. You want to minimize ground running time or taxiing downwind
which provides zero cooling.

I have towed aircraft for that reason
 
The previous owner 175 or so hours ago replaced all the pistons and rings. My 20 hours has been fairly ROP boring XC. So what the heck did they do? Two cylinders burning oil, and the third has a broken ring, burned cylinder, and too far out of spec to be able to be bored and honed. Getting a brand new set to replace it.

Maybe didn’t break in properly and ran too hot / too lean? Maybe they never bored and honed, never checked the valve guides?
 
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