Thumbs 1
Thumbs 1
Thumbs 1

Superior Millennium Cylinders SL10302-A21P

Select Cylinders:
Single Cylinder4 Cylinder Kit


Uniform hardness all the way through the steel barrel walls which allows the barrel to provide even wear while withstanding extreme cylinder temperatures and pressures.

Exhaust and intake ports are volumetrically matched to maximum output and performance.

Increased port wall thickness - eliminates problems with warping and cracking.

Computer-generated head fin configuration - deliver more uniform heat transfer and fewer "hot" spots.

Manufactured from the most advanced alloys available - exceed industry standard for strength and porosity.

+ Included with stud assembly.


Engine Configurations
O-235 -K2A, -K2B, -K2C, -L2A, -L2C, -M1


Parts per Assembly

  • 4 - Bushing, Rocker, Shaft (SL66610)
  • 1 - Exhaust Valve Guide (SL11626)
  • 1 - Intake Valve (SL11900)
  • 1 - Seat, Exh. (SL16699)
  • 1 - Guide, Int. Valve (SL61681A)
  • 1 - Fitting, Oil Drain (MS20822-6D)
  • 2 - Helicoil (MS9018-05/2-52)
  • 2 - Stud, 5/16 In Dia, Coarse Thrd (SL31C-12)
  • 1 - Plug (MS49005-2)
  • 2 - Seat, Valve, Spring (SL10077)
  • 2 - Inner Valve Spring (SL11795)
  • 2 - Spring (SL11800)
  • 1 - Valve, Exhaust (Rotor Type) (SL19034)
  • 1 - Valve, Intake (SL11901)
  • 4 - Key, Valve (SL60009)
  • 2 - Spring Seat (SL65441)
  • 2 - Thrust Button (SL12892)
  • 1 - Shaft, Rocker Valve (SL13790A)
  • 1 - Piston, Machined (SL18729)
  • 4 - Seal - Shroud Tube (SL18661)
  • 1 - Seal, Oil Ring (SL62869)
  • 1 - Gasket (SL71973)
  • 1 - Gasket (SL75906)
  • 2 - Piston Ring (SL78862)
  • 1 - Piston Ring Assembly (SL78864)
  • 1 - Cylinder Stud (SL10302-A1)
  • Frequently Purchased With
  • Customers Also Viewed


I was told upon ordering that the cylinder would come with the rings fitted and on the piston inserted in the bore. All I would need to do is pull the piston out far enough to get the new wrist pin into the connecting rod and bolt it up. The piston was in a box. The rings were not fitted to the bore and were in a box. There was no new wrist pin in the parts received. There is a rocker arm shaft but no piston wrist pin?

Hans M Verified Purchase


March 4, 2022


Please note, Aircraft Spruce Canada's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce Canada assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Do these come with new pistons and rings and installation gaskets and seals?

We have added an Assembly Parts tab to this web page. It lists all included parts.

Q: Do the SL66610 rocker shaft bushings come installed in the SL10302-A21P cylinder stud?

Yes those would be installed.

Q: What about valve covers?

It is included with this cylinder kit.

Q: are these cylinders going to give me less power than the original Lycoming cylinders?

No. These would not effect the power output of your engine.

View in Catalog

View Image View in Catalog