Much of our head skimming machine time is devoted to the Rover K series heads from both private and trade customers. The K series engines have been in production since the early 90’s and give good service with the exception of the head gaskets which have proved to be notoriously unreliable.
The head gaskets generally fail in one of two ways :-
- The rubber water seal around the outside edge or headbolt holes becomes detached from the steel headgasket and the resultant coolant loss causes overheating and gasket failure.
- The hollow nylon dowell which locates the headgasket and through which oil passes under pressure up to the cylinder head, deteriorates with age and allows oil to flow around its outside, eventually bursting the the rubber bead in the head gasket and pumping oil into the cooling system. The oil emulsifies and reduces the coolant efficiency, again resulting in overheating if left unnoticed.
The K series heads must be resurfaced (skimmed) following headgasket failure as they not only warp, but the fire ring section is very narrow and etches into the head face, reducing the sealing effect and causing a further failure. The latest multi layer steel headgaskets (MLS) virtually eliminate all of these failures, they are now supplied with steel locating dowells and a 0.020” steel shim which fits against the head and has the dual benefit of making up for any material machined from the head and spreading the load of the fire ring onto the shim, reducing the etching effect.
The excess heating of the cyinder head following gasket failure can also, in extreme cases, cause valve seat to guide alignment problems which allows gas to leak and a subsequent misfire. These heads are also usually annealed (softened) by overheating and should ideally be replaced or used with shims.
These effects and solutions are common to all the K. series Rovers including 1.1, and 1.4 8 valve and all 16 valve and V6 variants.
As information on the re-use of the headbolts is vague, the best solution is always replacement.