Wagner Tuning Head Stud Kit, BMW M20

BMW M20 Engine Pro-Series 18.8 Cylinder Head Stud Set

Replacing the original cylinder head screws with high-strength Pro-Series 18.8 studs is necessary when making large increases in performance, as the original cylinder head screws elongate during operation and the cylinder head can lift off.

The Pro-Series 18.8 stud bolts with a tensile strength of 1850 N / mm² provide a solution to this.

In addition, these stud bolts do not have to be replaced after dismantling, but can be reused.

Kit Contents:

(14) M10 Stud Bolts
(14) M10 Nuts
(14) Washers
Assembly Paste
Assembly Instructions

Tensile strength: PS 18.8 steel / 1850+ N/mm² (270.000+PSI)

A special steel is used which, after tempering, has a tensile strength of 1850 + N / mm².

All threads are formed and not cut as usual. The so-called rolling of threads can increase the strength of the tooth flanks by around 30%.

All Pro-Series products are supplied with a nickel coating or optional with a burnished protecting against corrosion in the long term, even under the toughest conditions. Pro-Series stud bolts have a hexagon socket drive on the head side for screwing in the stud bolts. Due to a cone on the engine block side of the bolt, these are not supported on the thread flanks when the nuts are tightened, but in the bore of the thread in the engine block. This support protects the threads when racing engines are frequently rebuilt.

Pro-Series advantage over other manufacturers is the nuts and washers included in the set, these also have a tensile strength of 1850 N / mm².

Application list:

From MY 1976-1992
BMW 320i E21 122PS
BMW 323i 143PS
BMW 325i 170PS
BMW325e 122PS und 129PS
BMW 520 E12 122PS und 129PS

Manufactured in Germany

Installation Instructions:

1. After unpacking ProSeries stud bolts, inspect all hardware prior to installation. Look for obvious defects or shipping damage. Contact our sales team immediately with any questions or issues.
2. Before mounting, compare the supplied bolts with the stock screws, paying particular attention to the thread type and length of the bolts.
Check existing threads inside engine block for damage. To ensure proper thread engagement and accurate torque readings, make sure that all threads are free from remnant sealer, lubricant, and debris. Check the flatness and surface finish of the engine block and cylinder head deck to avoid gasket failure.
3. Insert stud bolts into the engine block and tighten with a 5mm hexagon socket on the drive provided at the head of the stud bolt with a torque of 15Nm.
4. If the stud bolts are to remain permanently installed in the engine block, they can be used with screw lock (not included)
5. Attention! Before final mounting of Pro-Series nuts and washers, all contact surfaces must be completely wetted with the supplied special ProSeries lubricant.
If this will not be considered the applied tightening torque is falsified and the resulting clamping force is reduced. Under certain circumstances, this can also inevitably lead to the bolts breaking / shearing off.

6. Tighten nuts in three equal steps in the factory sequence. For the last pass, refer to the table shown below:

7. ProSeries studs and nuts can always be reused. When re-tightening or reassembling, please always ensure that all contact surfaces are wetted with special ProSeries lubricant. Please contact our sales team if you have any further questions.