BMW M20 Cylinderheads

BMW M20 Cylinderheads

While these heads, like most BMW heads, offer fantastic performance in stock form, they do leave some room for improvements. The biggest being precision valve seat work with one of our flow tested Serdi seat profiles. They also benefit from blending in the area beneath the valve seats.

In all cases our valve seat work alone is enough to realize significant power gains.

Our S.C.C.A. Improved Touring S (ITS) M20 cylinder head work has netted 2 American Road Race of Champions titles and an Atlanta Region Pro ITS Championship for prolific winner Matt Reppert. S.C.C.A. Improved Touring engine rules prohibit port work, limiting improvements to valve seat work only. Years of extensive flow testing give us a real advantage here and we have several race proven Serdi seat profiles.

Click here to read more about Matt Reppert’s winning ways.


When over-heated, these heads tend to crack between the cam journals, directly beneath the cam. They also crack beneath exhaust seats, across the deck out to a coolant port. The cracks beneath the cam can be terminal if the crack migrates through a cam bore. While we have the ability to make this repair, these heads are so common that they just aren’t worth the expense. Cracks through the exhaust are another matter. Repairs here are routine and affordable.

Another problem arises with these heads when the timing belt breaks. Since M20’s are interference engines, the pistons and valves collide. Aside from the bent valves and damaged valve seats, in some cases the valve-piston collision transfers through the rocker shaft into the head, leading to broken shaft bores. This repair is also routine for us. We weld in a replacement and align bore with the undamaged bores as a guide for proper shaft alignment.


Please Contact Us  to discuss your M20 cylinderheads.


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