2.0E Cylinder Head Damage

[deemde]

I have just removed the cylinder head from my 100 2.0E. It was running on two cylinders, with low compression on pots 1 & 2. The reason was a quite large groove in the cylinder head between 1 & 2 (about 2mm deep by 10mm wide). This looks to have been worn, perhaps burnt, into the land between the two combustion chambers.
Has anyone seen this before, or does anyone have any idea what might have caused the phenomenon?

 

[DaveACQ20v]

If you take the Head Gasket off and `match` it up to the cylinder head, you will probably find a hole in the gasket in the same place as the damage to the Head. It was probably the gasket that blew first, then through contunued use it has damaged the head. Is the groove too deep to be `skimmed` out ?

Just read your post again and 2mm does sound deep, infact it sounds more like a trough than a groove. Any pics ?

 

[deemde]

Makes sense Dave. Actually, I did not take the head off, the local VW dealers did it, so I did not see the gasket.
First time I have taken any of my cars to a dealers in 30 years, but water had got into the ECU. I had stripped and re-built the injection, before I spotted the problem. After curing the leaks, in the bulkhead to inner wing joints, I dried out the ECU. The car ran pretty well for a while, and then this (2 problems together difficult to spot). So I suspected faults with the ECU, hence, the dealers.
I have never had a gasket failure before, although I have owned, and still own, very high milage 4 cylinders (Mk I & II GTIs, Audi 80 & Coupe). My present MkII GTI has 200,000 on the odometer.