Tdi cylinder head bolt torque and sequence

[Ninjabob81]

Originally Posted by Martin Cox

As an aside, my head gasket and new bolts were supplied by the local engineering firm that sorted out the bent valves and stuck cam followers resulting from a broken cambelt. The original was of the thickness identified by two holes. Their replacement had three holes and was the thickest gasket available.

When I queried this they said "We only ever supply the thicker gaskets - there's no good reason not to." Since they did a first class job on the head, I've no good reason to doubt them.

Martin

The reason for the different thicknesses available is all down to tolerances when the engine was built, every engine is slightly different. Even slight differences in rod length, piston height etc will affect the piston protrusion. With this engine having a flat head face and the combustion chamber in the piston crown, piston protrusion is of massive importance. Not only will it affect compression ratio but in extreme circumstances the piston could contact the head. I’d alway follow what the manufacturer deemed right when they originally built it.

[Martin Cox]

I can appreciate that and I can certainly see the danger in fitting a thinner gasket than originally supplied.

My wife collected the cylinder head since I was away from home at the time or I'd have questioned them further about this.

I was surprised to find that they'd skimmed the head lightly since I'd been led to believe it shouldn't be skimmed. However it all went back together without any problem and has worked perfectly to date. Possibly the thicker gasket may have offset the skim.

Martin