Porsche Engine Case Machining: The Foundation For Successful Engine Builds

Porsche Engine Case Machining: The Foundation For Successful Engine Builds

Porsche Engine Case Machining

Accurate and quality machine work is critical for any engine build and is considered as part of the foundation for maximum reliable power output. In addition to building a wide range of Porsche engines here at Mountune USA, we also provide a complete Porsche engine case machining and processing program offering a wide range of services all done in house to the highest level on the latest CNC engine machining centers. We'll take a look at some of the machining services we offer for air cooled Porsche cases in this edition. 

The main bearing housing/tunnel in older engine cases or cases that have had high duty cycles are often out of round or enlarged. Returning the case back to standard original dimensions allows the use of standard size main bearings providing accurate oil pressure and heat dissipation.  We first resize the engine case by machining each case half mating surface and removing a small amount of material thereby closing up the main bearing tunnel bore and reducing the diameter below the standard dimension. This process is done on one of our CNC centers resulting in precise, flat case half mating surface providing complete sealing during final engine assembly.

Porsche Case half correction

Porsche machined case half

The case halves are then assembled using the original fasteners, torqued to original specification. The assembled case is then mounted in our Rottler F69A where we align bore the main bearing tunnel vertically. The vertical process yields a more precise and straighter tunnel compared to the horizontal method. We also machine the layshaft bore during the same operation.  Each case is then inspected and deburred and cleaned. 

Porsche Align Bore

Porsche Case Bore

We also bore cases for larger cylinders including the O-ring groove machining process if required. The case is mounted in our Rottler F69A on the main bearing tunnel. This setup ensures the connecting rods, pistons, and cylinders will be “square” to the crankshaft. Each spigot is inspected before and after machining for flatness and ovality by CMM.

Porsche CMM


Porsche case O ring

Engine component balancing is an often-overlooked process when building an engine but is essential to a smoother-running assembly. Additionally, vibration in the rotating assembly causes parasitic loss of power and can cause premature wear of components and the engine case. We balance the complete rotating assembly in-house to Formula One standards of 0.50g

Porsche crankshaft balancing

From complete engine assembly and testing to critical machine work, we have you covered across the air-cooled Porsche range. Contact us for pricing or more information at info@mountuneusa.com.

Back to blog
  • What Goes Into Every Mountune Crate Engine Build?

    What Goes Into Every Mountune Crate Engine Build?

    Mountune USA is at the forefront of engine performance, working with championship-winning teams to deliver reliable, podium-winning engines. With a strong team of experienced engineers and engine builders, Mountune USA...

    What Goes Into Every Mountune Crate Engine Build?

    Mountune USA is at the forefront of engine performance, working with championship-winning teams to deliver reliable, podium-winning engines. With a strong team of experienced engineers and engine builders, Mountune USA...

  • How much horsepower do mountune engines make?

    How much horsepower do mountune engines make?

    It's a common misconception to think that an engine "makes" horsepower on its own. In reality, horsepower is the result of a complex interplay between various factors, primarily the combination...

    How much horsepower do mountune engines make?

    It's a common misconception to think that an engine "makes" horsepower on its own. In reality, horsepower is the result of a complex interplay between various factors, primarily the combination...

  • Introducing the All-New Lightweight Aluminum Mountune Lower Intercooler Hard Pipes for Focus ST and RS!

    Introducing the All-New Lightweight Aluminum Mo...

    Our team of engineers has been hard at work to make our Lower Intercooler Hard Pipes even better. We've listened to your feedback and have completely reimagined this critical component...

    Introducing the All-New Lightweight Aluminum Mo...

    Our team of engineers has been hard at work to make our Lower Intercooler Hard Pipes even better. We've listened to your feedback and have completely reimagined this critical component...

1 of 3