928 Motorsports, LLC ®

928 Motorsports
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928 Motorsports

928 Motorsports
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928 Motorsports
928 Motorsports 928 Motorsports

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Wet Wall Cylinder Sleeves for Porsche® 928, 944, 951 and 968 Engines

STEEL CYLINDER WALLS FOR YOUR ALUSIL BLOCK: 928 Motorsports can remove your stock cylinder bores entirely and press in new steel wet cylinder sleeves, which permits larger bores and CID than ever before possible from these engines.

BENEFITS: High-ductile iron cylinder sleeves offer some unique benefits:

  1. Sleeving the engine to a 4.25" bore permits the use of standard forged pistons, with a reduction in piston cost of often over 200% from custom (metric) piston sizes.
  2. Sleeving with high-ductile, high strength iron is ideal for high-boost applications (15 psi and up) where an unsupported aluminum wall would crack and fail.
  3. An inexpensive way to add displacement. Imagine taking your 100mm bore Porsche 928 5.0L motor, and by sleeving to 4.250", you now have a 5.8 liter motor with the stock crank, and a 7.0L motor with our stroker crank!
ADDS SERVICABILITY: when an aluminum bore becomes scratched, the repair process either includes boring all cylinders to the next oversize dimension and buying all new pistons, or welding up the scratch, boring it down, and replacing the piston. Both expensive. Should a steel sleeve become scratched, the sleeve can be pulled out and a new one installed. Much less expensive!

O-RINGING and HEAD GASKETS: The custom T-top on the 928 Motorsports engine sleeves provides the ideal location for a stainless steel o-ring (optional) that will provided a positive seal on the head gasket against any amount of boost. The heads do not need to be modified with this design. Or you can order our MLS head gaskets and no o-rings are needed. Our large T-top sleeves provide a terrific sealing surface!


  • Ship your bare block to us at 928 Motorsports, LLC. Prepare your block by removing all the steel from the piston decks, like locating pins and head studs. Send just the bare block, no crank or rods installed. If there are steel parts in the block deck that you cannot remove, they will be removed for you but you will be charged extra for this service. The block does not have to be clean.
  • Let us know what your plan for Pistons is. It is smart to ship one of the pistons you want to use with the motor. This allows us to bore-to-fit that exact piston.
  • The price in this listing covers the standard 6-part process:
    1. Remove the stock cylinder walls down to the webbing, and bore the block as needed.
    2. The whole block is heated in to an oven and then the sleeves are pressed into place.
    3. The cylinder walls are honed to match the pistons.
    4. The decks are planed for flatness
    5. The o-ring grooves are cut into the top of the sleeves (optional).
    6. The finished block is tanked for cleansing before it is shipped. The cylinder walls will be lightly oiled to prevent surface rust and the block will be closed in a heavy engine bag for shipping.



Price (USD)


Porsche® 928 8 cyl Wet Wall Engine Sleeving Service


Motor Freight - Pay the Carrier

Porsche® 944, 951, 968 4 cyl Wet Wall Engine Sleeving Service

944, 951, 968

Motor Freight - Pay the Carrier

* Domestic US shipping shown. International shipping will be calculated based on location.

Phone: (920) 485-0928
Email: info@928motorsports.com

928 Motorsports, LLC - All Rights Reserved
Horicon, Wisconsin USA

928Motorsports.com - Performance Parts for your Porsche® 928