Pitting In "squish" Are On Cylinder Head

[JoshGti 8]

I picked up a spare head to build up and I've started cleaning it up, it's obviously had a rebuild either fairly recently or it wasn't fitted very long after being rebuilt as the valves are all numbered except the one that's obviously been replaced and the chambers are relatively clean. I'm going to cc balance the chambers but something concerning me is e piitting in the squish face part of the head face, looks like something has been in the cylinders chipping away at the face between the piston and head.

 

Shall I get my machinist to mill down flush till they're gone (they are about 0.5mm deep!) and use a so called "repair" head gasket or leave it? And just have it refaced.

 

Or measure the head depth and compare it to standard height and maybe get a vernier cam pulley to take advantage of the increased CR?

 

[dcc 855]

The head has to make a pretty good seal to the gasket to ensure all of the combustion gasses are sent out of the exhaust ports, as opposed through a weakened route to your oil/water.

 

I would not be happy using that in my engine ;/

[Sinbad 16]

I wouldnt use that,i have a spare head thats pitted badly like that,it was about 1mm deep on mine!

Take it to an engine reconditioners and see what they recommend.

[JoshGti 8]

I'm not overly concerned with using it after a skim as the damage is inside the fire rings on the gasket. Also this head isn't off my engine currently so there's no panic that it will get worse as the bits aren't floating around in my cylinders.

 

Edit: just measured it with pointy end of calipers and it's about 0.6 mm deep on the worst cylinder. Safest max skim is about 1.5mm (from what I've read) so it may all depend on how much has already been taken off?

Edited November 6, 2011 by JoshGti

[RossD 44]

I had a failure similiar to this on an HDi engine I had a few years ago. The damage was nowhere near as severe and the head had to have about 0.2mm taken off it, but it did cause MASSIVE pressurisation of the cooling system. That damage is far far worse and would probably cause similar symptoms.

 

My head was absolutely fine after a skim and rebuild.

 

[RossD 44]

I had a failure similiar to this on an HDi engine I had a few years ago. The damage was nowhere near as severe and the head had to have about 0.2mm taken off it, but it did cause MASSIVE pressurisation of the cooling system. Your damage is far far worse and would probably cause similar symptoms.

 

My head was absolutely fine after a skim and rebuild.

 

[JoshGti 8]

Cheers for the vote of confidence Ross I've got hold of a vernier so was kind of already going to give it a bash but this at least gives me some light at the end!