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Standard Replacement Parts
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 914 (1970-1976)
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
- Porsche 914 (1970-1976)
Sold each - 4 required per car
Fits:
Porsche 914 2.0ltr - 1970 to 1976
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
039198075
The product you are viewing cross references to these numbers
- Porsche 914 (1970-1976)
Sold each - 4 required per car
Fits:
Porsche 914 2.0ltr - 1970 to 1976
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
039198075A
The product you are viewing cross references to these numbers
Standard Replacement Engine Pistons – Precision Fit, Performance, and Longevity for Porsche Engines
Engine pistons are the beating heart of any Porsche power unit, converting combustion energy into motion and defining the engine’s power, efficiency, and character. Over time, even the most durable components wear out due to heat, friction, and high RPM operation — making precision replacement essential for restoring performance and reliability.
At Design911, we supply a full range of standard replacement pistons engineered to manufacturer-level tolerances for Porsche engines. Each piston is crafted from high-strength aluminium alloys and precision-machined for exact fitment, ensuring proper compression, reduced friction, and smooth engine operation.
Whether you’re rebuilding a classic air-cooled flat-six or
servicing a modern turbocharged model, our pistons are
designed to deliver dependable power and long service life without compromise
.What Do Engine Pistons Do?
Pistons play a central role in the combustion process, compressing air and fuel before ignition and transmitting force through the connecting rods to the crankshaft.
Core Functions:
- Convert
combustion energy into motion, powering the engine.
- Maintain
compression and sealing between the combustion chamber and crankcase.
- Ensure
smooth operation and balanced rotation within the cylinder bores.
- Regulate fuel efficiency and performance by maintaining correct clearances.
A set of well-balanced, precision pistons ensures optimal performance, reduced emissions, and reliable power delivery throughout your Porsche’s rev range.
Why Do Pistons Fail?
Pistons are subjected to extreme heat and pressure thousands of times per minute, which can eventually lead to wear or damage — particularly in high-mileage or performance engines.
Common Causes of Piston Failure Include:
- Wear
and scoring from contaminated oil or poor lubrication.
- Thermal
fatigue and cracking due to overheating.
- Detonation
or pre-ignition, damaging piston crowns and ring lands.
- Excessive
carbon build-up, affecting sealing and compression.
- Incorrect piston clearance or ring fitment during rebuilds.
Symptoms of piston wear include oil consumption, reduced compression, misfires, or smoke, all of which indicate the need for immediate inspection or replacement.
Why Replace with Precision-Engineered Standard Pistons?
Installing precision replacement pistons restores your Porsche engine’s power, efficiency, and mechanical balance. Designed for direct fitment with original tolerances, these pistons ensure a smooth rebuild process and reliable long-term performance.
Key Benefits:
- Restores compression and engine efficiency.
- Eliminates power loss and oil consumption.
- Reduces
friction and wear, extending engine life.
- Crafted
from heat-treated aluminium alloys for superior strength and
lightness.
- Perfect fitment for air-cooled and water-cooled Porsche engines.
- Ideal for restorations, rebuilds, and maintenance projects.
Precision pistons not only bring your engine back to life but also preserve the smooth, responsive performance Porsche engines are renowned for.
Highlights:
- High-strength
replacement pistons for Porsche engines.
- Precision-machined
surfaces for perfect sealing and performance.
- Balanced
weight design for smooth, vibration-free operation.
- Designed to meet or exceed manufacturer tolerances.
- Compatible with classic and modern Porsche models.
- Perfect for engine rebuilds, restorations, or preventative maintenance.