This is a complete valve train kit for the McLaren M838T engine found in the MP4-12C, 650S, 675LT, MSO 688HS, P1, 540C, 570S, 600LT, and 620R.

It is designed to eliminate the risk of broken valves which can occur due to the high tensile strength of the valves as a result of the black nitride coating process. With our variable thickness lash caps, this kit also allows for valve adjustment, a crucial maintenance item with engines lacking hydraulic lifters.

This kit comes with high grade stainless steel intake valves and Inconel exhaust valves. The valves are slightly lighter than OEM despite being 1/2mm wider than OEM. This allows for a deeper seat refinish if you prefer to reuse your existing valve seats and also a slight performance improvement over the stock. If you request OEM sizing, we can provide OEM diameter (please contact us directly before we ship your order to request this change).

The kit also uses bronze valve guides with a slightly higher hardness rating for increased longevity over the stock guides. New valve stem seals are also included, in addition to new Manley valve springs with 50% higher spring rate for increase performance and reduced chance of valve float, valve retainers, and varying thickness valve lash caps to allow for the perfect valve lash as required for your head. Valve seats are also available and are recommended to get the best heat transfer and performance from the Inconel exhaust valves.

This valve train kit is the ultimate upgrade to improve your McLaren’s reliability.