Cylinder head copper base gasket 0.25mm. Porsche 911 / 914  ›  90110419100

Cylinder head copper base gasket 0.25mm
Copper 0.25mm cylinder base gasket by Porsche for selected Porsche 911 models from 1965–73 and the 914-6 from 1970–76. This gasket fits between the cylinder barrel and engine crankcase during flat-six engine assembly.
Sold each

Fits:
Porsche 911 1965 - 1973
Porsche 914-6 1970 - 1976

Diagram ref no 26


What This Product Does

The gasket seals the joint at the base of the cylinder while maintaining the specified spacing between the cylinder and crankcase. Its thickness contributes to cylinder positioning and must be considered when measuring deck height and rebuilding the engine.

Functions

• Seals the cylinder-to-crankcase joint
• Provides a controlled 0.25mm base thickness
• Supports correct cylinder positioning during assembly
• Helps prevent oil seepage around the cylinder base
• Forms part of the sealing system for each cylinder

Technical Details

• Porsche reference: 90110419100
• Material: copper
• Thickness: 0.25mm
• Inner diameter: approximately 92.2mm
• Outer diameter: approximately 103mm
• Required quantity for a complete flat-six engine: 6

Internal application data also identifies use with 911 T-E/E, 911 T-V and 911 T-K engine or model variants. Confirm the required gasket thickness through the appropriate engine measurements before assembly.

Symptoms of Fault

• Oil seepage visible around the cylinder-to-crankcase joint
• A flattened, distorted or damaged gasket found during dismantling
• Previous use of unsuitable sealant around the cylinder base
• Incorrect cylinder height or deck measurements during an engine rebuild

Why Replacement Matters

A cylinder base gasket can become compressed or damaged after installation and should be inspected whenever the cylinders are removed. Installing the specified gasket helps restore the intended cylinder spacing and sealing arrangement. During a full rebuild, all cylinders should be measured and assembled consistently, with related seals, hardware and wear components checked while access is available.

OE Reference

• 90110419100
• 901.104.191.00

FAQs

• How many gaskets are required?
  Diagram data specifies six for a complete flat-six engine. Confirm the quantity needed for the work being undertaken.
• Can an old cylinder base gasket be reused?
  Replacement is advisable once the cylinder has been removed because the installed gasket may be compressed or distorted.
• Does gasket thickness matter?
  Yes. Base-gasket thickness affects cylinder positioning and should match the engine measurements and rebuild specification.
• What should be checked during installation?
  Inspect the cylinder and crankcase mating surfaces, verify deck measurements and check the associated seals and hardware.

Check fitment for your specific vehicle, model year and engine before ordering.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

90110419100

The product you are viewing cross references to these numbers