Wagner Tuning Head Stud Kit, BMW N55

BMW N55 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:

(4) M9 Stud Bolts
(10) M11 Stud Bolts
(4) M9 Nuts
(10) M11 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:

MY 2009 – 2015
135i E82/E88 306PS
135i E82/E88 326PS
M135i F20/F21 320PS
M135i F20/F21 326PS
M235i F22/F23 326PS
M2 F87 Coupe 370PS
335i F30/F31/F34/F35 306PS
335i F30/F31/F34/F35 326PS
335i F30/F31/F34/F35 340PS
335i E90/E91/E92/E93 306PS
335i E90/E91/E92/E93 326PS
435i F32/F33/F36 306PS
435i F32/F33/F36 340PS
535i F07 Gran Turismo 306PS
535i F10 306PS
535i F10/F11/F18 326PS
535i F11 Touring 306PS
640i F12/F13/F06 320PS
740i F01/F02/F03/F04 320PS
X1 35i E84 (USA) 306PS
X3 35i F25 306PS
X4 35i F26 306PS
X4 M40i F26 360PS
X5 35i F15 306PS
X5 35i E70 306PS
X6 35i E71 306PS

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.