M5X 12mm Head Stud & Gasket Kit
The ultimate way to prevent head lift on BMW M5X engines, especially the aluminum M54.
On our time-attack car we ran into head lift at high power levels when running at high temps for long durations on track. Even with a cut-ring head gasket, we still had issues. The clamping force of upgraded 10mm studs and timeserts just couldn’t provide what was required.
So, we decided to source specialty studs from ARP, which aren’t available in any kit, to retrofit into the M54.
Our kit includes a machined Cometic head gasket in a thickness of your choice that accepts the 12mm stud, ARP 2000 head studs, specialty washers that fit on the factory head pads, and narrow nuts to accommodate a large 14mm 12pt socket between the valve springs. And yes, it is expensive, but these are special order parts and includes the machining of the head gasket which requires specialty tools. Also does not require time-serts, which saves you a ton on the tool set needed to install them properly.
Please allow a week lead time for the head gasket machining. Hardware will be drop shipped direct from ARP.
The use of the 12mm head studs requires a machine shop to drill out your head holes to 12.5mm, along with rethread and counterbore your block. This is a straightforward procedure for any machine shop.
We have not had any issues since moving to 12mm studs.
The final torque value we recommend is 95ft lbs. First torque to 31, then 63, then 95.