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5150 AutoSport

5150 AutoSport Head Gasket & Head Stud Kit, BMW M20

5150 AutoSport Head Gasket & Head Stud Kit, BMW M20

Regular price $449.99 USD
Regular price $499.99 USD Sale price $449.99 USD
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Head Gasket Type - Bore - Thickness
Head Stud Kit

Performance Head Gaskets & ARP Head Stud Kit for BMW M20 Engines

Upgrade your BMW M20 engine with high-performance head gaskets and ARP head studs designed for maximum reliability under extreme conditions.

Cometic MLS Head Gasket

The Cometic MLS (Multi-Layer Steel) Head Gasket is a premium replacement for BMW part numbers 11121722734, 11121722735, 11121722737, and 11121722738, fitting M20B20, M20B23, M20B25, and M20B27 engines in BMW E12, E21, E28, E30, and E34 models. MLS gaskets provide superior sealing for high-compression, turbocharged, and supercharged applications by resisting shearing forces and minimizing bore distortion. Made from multiple layers of stainless steel, they are corrosion-resistant and ideal for engines subjected to high temperatures and pressures.

Specifications:

  • M20B20 / M20B23: 80mm bore, 0.070" thickness
  • M20B25 / M20B27: 84mm bore, 0.070" thickness

This gasket is not compatible with engines using O-rings or receiver grooves, as it requires a smooth, flat surface to seal properly.

Athena Cut Ring Head Gasket

For high-boost applications exceeding 16 psi, the Athena Cut Ring Head Gasket is the preferred choice. It features AISI 304 stainless steel Cooper Rings that bite into the aluminum head for maximum sealing, preventing leaks that can lead to power loss or engine failure. Made from OE-approved reinforced M0115 material, this gasket is designed to withstand extreme cylinder pressures in turbocharged and nitrous applications exceeding 2 bar boost.

Key Benefits:

  • Handles extreme pressure better than OEM or MLS gaskets
  • Prevents compression leaks and overheating
  • Should be 0.5mm to 1mm larger than piston size for proper fit

Installation Notes:

  • Ensure cylinder head and block surfaces are clean, flat, and properly resurfaced
  • Do not use additional sealants
  • Follow proper torque specifications and sequence for even clamping force

ARP Head Stud Kit (201-4305)

For maximum durability, pair your head gasket with ARP 201-4305 Head Studs, engineered for BMW M20B20, M20B23, M20B25, and M20B27 engines. These high-strength studs provide increased clamping force, preventing head gasket failures in high-boost and performance builds.

Why Choose ARP Studs?

  • Stronger than OEM bolts for improved head gasket sealing
  • Essential for high-boost and turbocharged applications
  • Reduces the risk of head lift under extreme pressure

Before installation, always check and resurface the cylinder head and block to ensure they are completely flat for a proper seal.

Installation Instructions: 

1. To ensure proper thread engagement and accurate torque readings, clean ALL threads in the block. Chase if necessary with ARP Thread Chaser.
2. Clean and inspect all hardware prior to installation. Look for obvious defects or shipping damages, plus proper fit, length and dimension.
3. If the cylinder head studs protrude into a water jacket, lubricate the block threads of the studs with ARP THREAD SEALER.
4. Screw studs into the block “HAND TIGHT ONLY”.
5. Install the cylinder head(s) and check for binding or misalignment.
6. Lubricate the stud threads, nuts and washers with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT.
Then install the washers and the nuts onto the studs and tighten them hand tight.
ARP recommends using the ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT that is provided with each kit as opposed to motor oil. This is due to higher friction on the studs as well as inconsistencies in the clamping force of the fasteners when motor oil or other low quality lubricants are used.

PRELOAD (TORQUE) RECOMMENDATIONS

7. Following the manufacturers recommended torque sequence tighten the nuts steps 1-3

Step 1: Tighten to 25 ft-lbs.
Step 2: Tighten to 50 ft-lbs.
Step 3: Tighten to 70 ft-lbs.

with ARP Ultra-Torque fastener assembly lubricant

Bolt Torque Sequence

 12  10 4 2 6 8 14
13 7 5 1 3 9 11


BMW M20B20 Applications:

BMW 3 Series

1977-1982     E21     320 / 326
1982-1994     E30     320i

BMW 5 Series

1977-1981     E12     520 / 526
1981-1987     E28     520i

BMW 7 Series

1981-1987     E23     720i

BMW M20B23 Applications:

BMW 3 Series

1977-1982     E21     323i
1982-1994     E30     323i

BMW M20B25 Applications:

BMW 3 Series

1985-1993     E30     325i / 325is / 325ix

BMW 5 Series

1987-1990     E34     525i

BMW M20B27 Applications:

BMW 3 Series

1982-1987     E30     325e / 325es [North America]

BMW 5 Series

1982-1987     E28     525e / 528e

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