Tearing down a old 5.3 I yanked out of my silverado to rebuild, and one exhaust valve seems to look different than the rest. The engine had a bad pcv valve and burned quite a bit of oil due to it. But also had a antifreeze burning issue that I was hoping was a bad head gasket, but couldn’t find a bad spot in the head gasket at all. Anyone know what would cause the one exhaust valve on the far left cylinder to look like this? Trying to figure out if they’re worth getting checked out and reused. They’re 706 and I don’t believe they’re castec heads

 

You say you don't believe they are Castech castings, flip them over and post a pic.

 

The combustion chamber indicates she is burning a lot of oil. The exhaust valve though is fairly normal and not much different from the rest. That cylinder might have an issue with its oil ring or the cylinder itself could have damage such as a scratch or scoring.

Look for the battery symbol on the top side of the head.

That being said, not all 706 heads are castech and not all castech heads are bad. Castech also did 243 heads as well. Some 862's heads have also suffered the same fate.

If in doubt, have them Pressure checked by a competent machine shop. Some companies weld around these problem areas as a preventive measure and extra insurance.

 

This is how some rebuilders are dealing with it.

 

I’ll have to check again tomorrow when I go back out there. I do remember the valve cover looking like that when I popped it off when I originally pulled the motor tho. Maybe I didn’t look in the right place for the symbol

 

Well I finally got back out to look at them and they for sure have the castec symbol under the rockers. Didn’t look he’s enough for any cracks since they’re covered in oil and don’t have and cleaner but I’m going to assume that it’s where the antifreeze was going. So what’s the best heads to replace the 706’s with that won’t hurt power from loosing compression?

 

#862 heads, interchangeable with the 706, same combustion chamber size. Different manufacturer that uses a rougher casting process. Most give then a light porting job to smooth them out.