Replacing Head Studs in Air-Cooled Porsche Engines: A Step-by-Step Guide

Replacing the head studs is a crucial part of rebuilding any air-cooled Porsche engine. This is especially true if your engine is equipped with Dilavar studs, which are known for their tendency to break. In our latest YouTube video, we demonstrate how to replace and install head studs properly, ensuring a strong and reliable engine build. Here's a detailed guide to accompany the video.

Why Replace Head Studs?

Head studs play a critical role in maintaining the structural integrity of your engine. Over time, factory studs, especially Dilavar ones, can fail, leading to serious engine issues. Upgrading to high-performance head studs, such as ARP 204-4206, ensures durability and eliminates the need for future replacements. These studs are designed to be the last ones you’ll ever need.

Porsche ARP Head Studs 204-4206

Step 1: Preparation

Before installing new head studs, some essential preparation work is required:

Running a tap or thread chase to ensure threads are good in the block.

1. For Aluminum Cases:

• Run a thread chaser through the head stud bosses to clean and prepare the threads.
• If the studs don’t thread in far enough, use a forming tap to correct the threads.

2. For Magnesium Cases:

   • Install steel case savers to strengthen the thread bosses. This step is critical for ensuring the studs remain secure over time.

3. Timing:

• Perform these operations before starting engine assembly.

Step 2: Installing the Head Studs

1. Threading the Studs:

• Studs should thread into the case by hand if the threads are clean and prepared.
• If manual threading isn’t possible, use a double-nut method or a stud installation tool to fit the studs.
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  Threading the head studs into the engine case.

2. Using Loctite:

• Apply Loctite to the threads if recommended for your application. This helps secure the studs to the case.
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  Proper application of loctite to cylinder head studs

3. Avoid Bottoming Out:

• Take care not to overtighten or bottom out the studs during installation.

Step 3: Fitting the Cylinder Heads

Fitting the cylinder heads

1. Preliminary Assembly:

   • Once the Porsche cylinder and piston assemblies and heads are fitted, install the nuts and washers onto the studs.

2. Lubrication:

   • Lubricate the stud threads, nuts, and washers with the ARP assembly lube provided with the kit.

3. Hand Tighten:

• For initial assembly, tighten the nuts by hand to secure the heads in place temporarily.

Step 4: Torquing the Head Studs

Proper torque sequence for Porsche cylinder heads when using ARP studs

1. Follow ARP’s Torque Procedure:

   • ARP specifies a final torque value of 38 ft-lbs when using their lube.
   • Torque the nuts in two equal steps, following the sequence outlined in the ARP installation manual.

2. Verify Fitment:

• Ensure the cylinder heads are seated properly before proceeding with final assembly.

Torquing the cylinder head fasteners

Step 5: Post-Build Maintenance

• Retorquing the Heads:
• Some engine builders recommend retorquing your Porsche cylinder heads after the engine break-in period, typically done alongside a valve adjustment.
• However, ARP states that this step is not mandatory.

Final Thoughts

Replacing head studs during an engine rebuild is essential for ensuring long-term reliability and preventing failures. High-performance studs like the ARP 204-4206 provide the ultimate peace of mind, allowing you to focus on enjoying your air-cooled Porsche.

For a full walkthrough of the process, watch our video: Replacing Head Studs in Air-Cooled Porsche Engines. If you have any questions or need advice, leave a comment—we’re here to help.

Watch the Video Now!

Installing the cam towers