Ok, I spent some time this weekend making a cutaway of the bad cylinder head (#8 cylinder) I replaced last summer. "Why?", you ask. Well, the old heads were taking up room in my 1-car garage and I wanted to save for future "victims" what this crack looks like in the iron before scrapping the heads. I used a band saw to cut out just the #8 cylinder and also show cross-sections of the intake/exhaust ports, and water jacket. In my case, the crack is most prominent on the intake seat, but it extends across to the exhaust seat and up the side of the exhaust valve pocket. If this had been allowed to go on longer, I'm sure it would have cracked through to the water jacket. BTW, the plug is the original one I broke off trying to remove. Here are the links:

Bottom View:


Intake Side View:


Exhaust Side View:


Crack Between Seats 1:


Crack Between Seats 2:


Crack Between Seats 3:


Crack Between Seats 4:


Crack Going Up Exhaust Side:


Crack Going Into Intake Side:


I don't know what caused the crack, but this cylinder does have FOD damage. I believe a spark plug electrode broke off at one time. You can see the gouge taken out of the CC in the last pic. I finally determined it was the dreaded crack after performing a leak down test. Air was pouring out the intake, even through that tiny crack. This is why I'm a constant broken record about perfoming a compression test when noobs get on here wanting to by a Dodge. Take heed of the $2,000 paperweight!

 

Very nice pictures!

 

So, now what's the problem again? You know, there's an easier way to check if the plug was indexed or not.








In all seriousness, were you getting a misfire you could feel, or was it just the random flashing CEL?

I think I figured out that my random CEL was a bad crank sensor, but with all that pinging going on, I'm hoping I didn't start a crack in the cylinder head.

 

truth be known I'd wager 10-25% of iron cylinder heads on the road today have cracks in them somewhere. I have seen perfectly good running engines toe down for rebuilds that had cracks just like that on the valve seat areas. I have yet to see a 6.5 Chevy diesel head that didn't have cracks in the injector area.

 

holy shi+... makes me think about mine.

 

don't sweat it man, if it ain't broke don't fix it. The famous 2.02 camel back chevy heads were notorious for having cracks and guys run those things like that hard for years and years.

 

Thanks, PC. They were hastily taken with a Cannon S500. I can only get so close with that thing.

 

I was getting a misfire you could really feel at idle and a solid CEL, misfire #8. None of my other cylinders ever misfired.

 

+1 madd props. I honestly always wondered what the crack would look like.

 

Can't argue with that, but if they go through the entire seat, then you've got a dead (or dying) cylinder. If I had had a compression test run before buying it, the problem would have presented itself.