Precision Machining for Aircooled and Watercooled Porsche Engines

LN Engineering is a Porsche engine machine shop specializing in precision machining for aircooled and watercooled Porsche engines. We support professional engine builders, repair shops, restoration facilities, and individual Porsche owners with the specialized machining required for engine repair, rebuilding, restoration, and performance upgrades. Our work includes Porsche engine case machining, cylinder boring and honing, Nikasil and Alusil cylinder reconditioning, Nickies sleeving, cylinder head machining, connecting rod reconditioning, crankshaft work, dynamic balancing, and precision inspection.

Our machine shop supports the RND Engines and Flat 6 Innovations Porsche engine rebuild programs as well as outside customer work. Whether you are rebuilding an early aircooled 911 engine, repairing a scored M96 or M97 block, reconditioning an MA1/9A1 Alusil engine, or preparing a performance engine for increased displacement, LN Engineering combines Porsche-specific experience with modern CNC machining, metrology, and quality-control equipment.

Porsche Engine Machining Services

• Porsche engine case machining and case repair
• Align boring and main bearing tunnel machining
• Case decking and cylinder spigot machining
• Machining for larger cylinders and increased displacement
• O-ring machining, shuffle pinning, and cylinder head stud inserts
• Cylinder boring, honing, and bore geometry correction
• Nikasil and nickel-silicon-carbide cylinder reconditioning
• Lokasil and Alusil cylinder bore repair
• Nickies aluminum cylinder sleeving
• Porsche cylinder head inspection, machining, and rebuilding
• Valve guide replacement and precision valve seat machining
• Connecting rod inspection and reconditioning
• Crankshaft inspection, polishing, grinding, and straightening
• Dynamic balancing of Porsche rotating assemblies
• CMM inspection, laser scanning, and dimensional verification

Need Porsche engine machine work? Contact LN Engineering with your Porsche model, engine type, the components you need machined, and a description of the damage or planned build. We work with customers and professional engine builders throughout the United States.

LN Engineering is a proud member of and contributor to the AERA Engine Builders Association.

Porsche Engine Case Machining

Porsche engine cases should be measured before any machining is performed so the repair plan can be based on the actual condition of the case. Main bearing tunnel alignment, case deck flatness, cylinder spigot geometry, bore condition, and the relationship between critical machined surfaces all need to be considered before material is removed. This is especially important on older magnesium and aluminum aircooled Porsche engine cases where decades of heat cycles, fretting, and previous machine work may have changed the original geometry.

Align Boring and Main Bearing Tunnel Machining

Worn aircooled Porsche engine cases may require align boring or main bearing tunnel correction when the bearing bores are no longer round or properly aligned. Magnesium 911 cases are especially known for requiring corrective machining during a proper rebuild. Where suitable oversize line-bore bearings are available, the case can be machined back to the correct geometry rather than discarded. Main bearing tunnel measurements should be evaluated together with crankshaft condition and intended bearing clearances before machining begins.

Case Decking, Cylinder Spigots and Larger Cylinders

Case decks and cylinder seating surfaces must be flat, square, and consistent if the engine is going to seal correctly and maintain uniform deck height. LN Engineering can resurface Porsche engine cases, machine cylinder spigots for larger cylinders or machine-in cylinders, and perform O-ring machining where appropriate for the build. Oversized cylinders and pistons can also be used to increase displacement and compression ratio when the engine combination is designed around those changes.

Shuffle Pinning, Case Savers and Aircooled Porsche Case Repair

Depending on the engine case and intended use, aircooled Porsche case preparation may also include shuffle pinning and installation of cylinder head stud inserts or case savers. These operations should be performed as part of a complete dimensional evaluation rather than as isolated modifications, since case condition, main tunnel alignment, deck height, cylinder fit, and intended power level all influence the final machining plan.

Porsche Cylinder Boring, Honing, Nikasil Reconditioning & Sleeving

Cylinder bores need to be inspected for diameter, ovality, taper, cylindricity, and surface finish before a repair method is selected. Although Nikasil is extremely durable, worn or damaged plated cylinders can require stripping, dimensional correction, replating, and finish honing. Porsche engines using Lokasil or Alusil cylinder bores may also require boring, direct plating, or sleeving depending on the engine family, severity of damage, desired bore size, and whether the original cylinder structure is suitable for reuse.

LN Engineering pioneered the use of aluminum nickel-silicon-carbide plated Nickies cylinders and sleeves for Porsche engines. Unlike cast iron or steel sleeves, aluminum sleeves provide thermal expansion characteristics and heat transfer that are better suited to an aluminum engine block. On M96 and M97 engines, Nickies also replace the original Lokasil cylinder structure and can address cylinder cracking, slipped sleeves, d-chunk failures, and severe Porsche cylinder bore scoring. Oversize pistons can be used where the finished bore is larger than stock, allowing increases in displacement and performance when appropriate for the build.

Watercooled Porsche M96, M97 and MA1/9A1 Engine Machining

Watercooled Porsche engines require different machining strategies depending on the engine family and cylinder technology. M96 and M97 engines use Lokasil cylinder structures and may require full Nickies sleeving when repairing severe bore scoring or structural cylinder damage. Later MA1/9A1 engines use Alusil blocks and, in many cases, can be repaired without full sleeving using LN Engineering’s Nickies Lite MA1/9A1 cylinder reconditioning process. The correct repair depends on bore damage, remaining parent material, desired final bore size, piston choice, and the goals of the engine build.

Porsche Cylinder Head Machining & Rebuilding

LN Engineering provides complete Porsche cylinder head inspection, cleaning, machining, and rebuilding services for aircooled and watercooled applications. Services include crack and warpage inspection, vapor and soda blasting, ultrasonic cleaning, CBN resurfacing for the required gasket finish, valve and spring inspection, valve guide replacement and honing, precision Serdi valve-seat machining, valve stem-height correction, vacuum testing, and final assembly. Performance services such as porting, polishing, and twin-plug machining are also available where appropriate.

Because Porsche cylinder head rebuilding is a specialized service with its own inspection, machining, and assembly requirements, we maintain a dedicated page with more detail on our process. Learn more about Porsche Cylinder Head Rebuilding Services.

Porsche Connecting Rod Reconditioning

Porsche connecting rods should be inspected carefully during an engine rebuild because dimensional errors, fatigue, or fastener problems can compromise bearing clearance and engine reliability. If your engine is undergoing a rebuild, it may be possible to refurbish and reuse the connecting rods, but we do recommend upgrading the connecting rod bolts. The reconditioning process involves cleaning the rods, testing their hardness to confirm the metal’s strength and composition, magnaflux testing for cracks, and checking for straightness. Additionally, the rod bolts and end cap bores are examined for stretch and roundness. Rod bolts are replaced and the caps are ground and big end bores honed to restore the housing bores to factory specifications. Once reconditioned, the connecting rods are ready for reuse in the engine rebuild. Our machine shop also offers services to press and hone new pin end bushings as well.

Porsche Crankshaft Inspection, Polishing, Grinding & Balancing

If a crankshaft is damaged by normal wear or a bad bearing, it may be able to be refinished and reused. Most Porsche crankshafts don’t need to be ground and can simply be polished as part of the reconditioning process, assuming the crankshaft is straight and has been magnafluxed to make sure it’s not cracked.

If the crank does need to be ground, crankshaft grinding is a process that removes a small amount of material from both the rod and main crank journals to return the crankshaft to OEM specifications, if possible. Most crankshafts can be ground, but some do require heat treating to restore journal hardness to ensure proper longevity. This may require the use of undersize bearings to ensure proper engine operation or even line bore bearings if the block needs to be resized at the same time. The crankshaft and entire rotating assembly can also be dynamically balanced during the process to help ensure the engine runs smoothly. Having a crankshaft polished or even ground can be less expensive than replacing the crankshaft when rebuilding an engine, so let our experienced professionals handle all of your crankshaft polishing, grinding, straightening, machining, and balancing needs.

Precision Inspection & Quality Control

Machining is only as good as the measurement used to verify it. LN Engineering maintains a dedicated temperature- and humidity-controlled QC lab and clean room with calibrated precision measurement equipment from Sunnen, Mitutoyo, and other leading manufacturers. VeriSurf CMM and laser-scanning capability allow us to inspect critical dimensions, compare machined components to CAD data, document geometry, and reverse engineer components when required.

Depending on the component and operation, inspection can include bore diameter, taper, ovality, cylindricity, main bearing tunnel alignment, deck height, surface finish, crankshaft journal dimensions, connecting rod housing bores, valve-seat concentricity, and other critical dimensions. Our goal is not simply to perform a machining operation, but to verify that the finished component meets the requirements of the engine build.

CNC Machining & Metrology Capabilities

LN Engineering is equipped with Haas 3-, 4-, and 5-axis CNC machines with Renishaw probing systems and thru-spindle coolant. We use SolidWorks, Fusion 360, and Mastercam for modeling and CAD/CAM, along with laser scanning and CMM inspection for verification and reverse engineering. These capabilities allow us to handle both traditional Porsche engine machining and specialized custom work where fixtures, tooling, or non-standard machining strategies are required.

Porsche Models & Engines We Machine

LN Engineering works on a wide range of Porsche engine families. Aircooled applications include Porsche 356, 912, 911, 930, 964, and 993 engines. Watercooled applications include 986 Boxster, 996, 987 Boxster and Cayman, 997, 981, 991, and later Porsche engines where the required machining operations are within our capabilities. We also work with individual engine components from Porsche race, Turbo, GT, and specialty applications.

If you are unsure whether we can machine your specific Porsche engine case, block, cylinder, crankshaft, connecting rods, or cylinder heads, contact us before shipping the parts so we can review the application and planned work.

Shipping Your Porsche Engine Components to LN Engineering

You do not need to bring us the complete vehicle. Porsche owners, repair shops, restoration facilities, and professional engine builders regularly ship engine components to LN Engineering for inspection and machining. Before sending parts, contact us with the engine type, the reason for the rebuild or failure, the components being sent, and the intended final build.

1. Identify the Porsche model, engine type, displacement, and intended use.
2. Tell us what failed or why the engine is being rebuilt.
3. Identify the case, block, crankshaft, rods, cylinders, heads, or rotating assembly being sent.
4. Tell us about any previous machining, repairs, or planned displacement changes.
5. We inspect and measure the components before finalizing the required machining operations.
6. After machining and final inspection, components are returned ready for the next stage of assembly.

Porsche Engine Machine Shop FAQ

Do you only machine Porsche engines?

Porsche engine machining is our primary specialty, but we also perform specialized machining for other performance and specialty engines when the required operations fit our equipment and capabilities. Contact us with the application and requested work so we can determine whether the project is a good fit.

Can I send only the engine case or individual parts?

Yes. We routinely work with individual engine cases, blocks, cylinder heads, crankshafts, connecting rods, cylinders, and rotating assemblies. Contact us before shipping so we can confirm what should be included and what measurements or related parts may be needed for the machining operation.

Do you work with professional Porsche engine builders and repair shops?

Yes. LN Engineering works directly with independent Porsche repair facilities, restoration shops, race shops, and professional engine builders as well as individual owners. Our machine-shop services are intended to support both complete engine rebuild programs and individual machining operations.

Should Porsche engine parts be measured before machining?

Yes. The cause of failure and the existing geometry should be established before corrective machining begins. Measuring first helps determine whether components can be reused, whether stock dimensions can be retained, what oversize parts may be required, and which machining operations are actually necessary.

Request Porsche Engine Machine Shop Services

Let LN Engineering assist with your Porsche engine repair, rebuild, restoration, or performance machining project. We stock many of the parts required to rebuild aircooled and watercooled Porsche engines, allowing us to support both the machining work and the components needed to complete the build.

When contacting us, include your Porsche model, engine type, planned displacement, the parts you need machined, and a brief description of the failure or build goals. If there is a service you do not see listed, contact LN Engineering directly to determine whether we can accommodate the required machining.