Cylinder Head differences

[Kyleman93]

My engine "ran away" because I accidentally installed the shutoff lever 180 out and it increased fuel instead of cutting it. My heads are junk, but I have heads off my parts engine that I am rebuilding, the parts heads have a completely flat surface and my old heads are ground about 3/16" between the valve seats. I was wondering, aside from the boost in compression, would these heads cause any other issues? It doesn't appear to be for airflow, and I haven't been able to find any info about it.

 

[NY Tom]

I could only speculate but I am curious what it could be for as well. I hope someone knows more.

Hard to believe they would cause any harm though if they were off a previously functioning engine.

 

[87cr250r]

I'm guessing that is for stress relief to prevent cracking between the valve seats. It isn't an uncommon feature of higher horsepower engines.

It may promote stress relief by encouraging cracking in acceptable areas. The heads on 6.2/6.5 diesels have similar relief and will typically crack in that area. The cracks are mostly superficial.

It's called valve bridge cracking. SAE has some articles on it if you have $33 to burn. I thought this was interesting, a Cat C15 only relieves between 2 of 4 valves.

Not my pic:

 

[Kyleman93]

I'm guessing that is for stress relief to prevent cracking between the valve seats. It isn't an uncommon feature of higher horsepower engines.

It may promote stress relief by encouraging cracking in acceptable areas. The heads on 6.2/6.5 diesels have similar relief and will typically crack in that area. The cracks are mostly superficial.

It's called valve bridge cracking. SAE has some articles on it if you have $33 to burn. I thought this was interesting, a Cat C15 only relieves between 2 of 4 valves.

Not my pic:
View attachment 886233

I've seen a lot of superficial/benign cracks in 6.0 powerstroke heads, I've done a lot of them. Every now and then you have a complete failure though. Long story short, I'm no stranger to engine work. I may see if I can get a machine shop to grind some reliefs. That cat has a relief there because it's the hottest spot in the head.