90 X 66 Piston & Cylinder Kit, Type 4/ 914 1700cc Engines

Product Overview

When it is time to breathe new life into your classic 1700cc Type 4 engine, choosing a high-quality, precision-engineered piston and cylinder kit is the most critical decision you will make. This 90mm x 66mm kit from AA Performance Products is the definitive solution for owners of early Volkswagen Buses and Porsche 914 models looking to restore factory-spec performance and reliability. Designed as a direct "slip-in" replacement, this kit requires no machining of your engine case or cylinder heads, making it the ideal choice for a weekend engine refresh or a complete concours-level restoration. These components are manufactured to exacting tolerances to ensure that your air-cooled engine maintains the proper compression ratios and thermal efficiency required for long-distance cruising and daily driving alike.

Engineering excellence is at the forefront of this kit''s design. The cylinders are cast from high-grade iron to provide a stable and durable bore surface that resists warping under the intense heat cycles typical of an air-cooled environment. The pistons are crafted from a hypereutectic cast aluminum alloy, which offers superior thermal expansion control and high-silicon content for increased wear resistance. This combination ensures that the piston-to-wall clearance remains consistent, reducing "piston slap" during cold starts and maintaining a tight seal at operating temperatures. Whether you are hauling a full load in your Westfalia or carving corners in a 914, this 1700cc kit provides the structural integrity and smooth power delivery that your vintage Volkswagen demands. Don''t settle for inferior components when you can install the industry standard for Type 4 longevity.

Vehicle Fitment & Compatibility

• Volkswagen Bus (Type 2): 1972-1973 (1700cc Type 4 Engines)
• Porsche 914: 1970-1973 (1.7L Engines)
• Engine Type: Type 4 Air-Cooled Flat Four
• Note: Direct fit for 66mm stroke crankshafts and standard 1700cc case/head registers.

Technical Specifications

• Bore Diameter: 90mm
• Stroke Compatibility: 66mm (Standard 1700cc)
• Total Displacement: 1700cc
• Cylinder Material: High-Strength Cast Iron
• Piston Material: Hypereutectic Aluminum Alloy (Cast)
• Wrist Pin Diameter: 24mm
• Kit Includes: 4 Pistons, 4 Cylinders, 4 Wrist Pins, 8 Circlips, and a Complete Set of Piston Rings.
• Installation Style: Slip-in (No machining required for stock 1.7L components).

Pro Tips from the Appletree Specialist

1. Precision Ring Gapping and Staggering

Even though this kit comes with a high-quality ring set, a master builder always verifies the end gap of every ring before final installation. Place each ring into its respective cylinder and use a feeler gauge to check the gap against factory specifications. Once verified, ensure that the ring gaps are staggered 120 degrees apart around the piston. Never align the gaps with the wrist pin axis or with each other, as this will lead to "blow-by," excessive oil consumption, and a loss of compression. Taking the time to index your rings properly is the difference between an engine that lasts 10,000 miles and one that lasts 100,000 miles.

2. Checking Deck Height and Compression Ratios

On Type 4 engines, maintaining the correct deck height (the distance from the top of the piston at TDC to the top of the cylinder) is vital for avoiding detonation and ensuring proper flame travel. We recommend a minimum deck height of .040" to .060". If your deck height is too tight, you can use copper base shims to lift the cylinder. Conversely, if it is too deep, your compression will be too low, leading to a sluggish engine. Always mock up your cylinders without rings first to measure this distance accurately across all four cylinders to ensure a balanced and smooth-running engine.

3. Critical Break-In Procedure and Lubrication

The first 20 minutes of your engine''s life determine the longevity of the piston-to-cylinder seal. Always use a high-quality break-in oil with high ZDDP (zinc and phosphorus) content to protect the camshaft and help the rings seat against the cast iron cylinder walls. Avoid synthetic oils during the initial break-in phase, as they are often too "slippery" to allow the rings to properly hone the cylinder surface. During the first start-up, vary the RPM between 2,000 and 3,000never let the engine idle for long periods during the first half-hour. This ensures sufficient oil pressure and splash lubrication to the wrist pins and cylinder walls while the rings are finding their final home.