Cylinder head scratch

[Zrain25]

I got a block head and cranks for 100 buck tool it home started to tear it apart. Block has already be decked and honed

The head has nothing done to it. I took All the valves,springs, and all that stuff out when I was cleaning it I noticed a pretty good scratch in head. It's located in front of the number 1 cylinder valves. I took a pic but sometimes they don't upload

How deep of a scratch is to deep my fingernail catches it

 

[Nick M]

.1mm or .0039". In other words, you would need a thicker metal headgasket.

 

[nosman4]

It depends on where the scratch is. If it crosses a firing line, then anything that your fingernail catches is way too deep. If it's away from any sealing rings around cooling jackets, oil passages, etc... It's probably fine.
Ian

 

[Zrain25]

Machine shop said he can probably get it out without a problem

 

[Nick M]

If you read the manual in the link, you will find Toyota engineers think the head should be discarded at a certain depth. Strength is compromised. A metal headgasket has shown to be ok if done right and the appropriate thickness. Your deck is still not as strong if beyond that boundry.