CYLINDER HEAD DAMAGE

I own a 1990 Ford Sierra 2.0 DOHC which has covered 105,000 miles. I’m presently in the process of replacing the head gasket and during this time I’m also going to replace the timing chain.

When the cylinder head was removed I discovered a small crack in the gasket, which was the cause of my original problem. Whilst attempting to clean the face of the cylinder head I have scratched the surface slightly and was considering having the cylinder head skimmed.

However, my Haynes manual states that the cylinder head should not be skimmed, and so now I am wondering what I should do. Nevil Long The Cylinder head can be skimmed provided this has not been done previously, the engineer who carries out the work should hopefully have all the data required to enable them to skim the head within the tolerances. You should use a machine shop that is a member of FER (Federation of Engine Remanufacturers).

There is only a small amount of metal that can be taken off when skimming the Sierra cylinder head, but this should be sufficient for the required rebuild. The cylinder head on these engines are also known to suffer from internal cracks close to the valve seats. So I would also recommend that the cylinder head is pressure tested and check for any distortion prior to having it skimmed.

When replacing the cylinder head, you should ensure that the cylinder head bolts are replaced with the newer version which have the washer built into the head, as opposed to lose on the shaft.