Exhaust valve condition

[jeremy3s]

I'm replacing the valve stem seals and doing a lap grind on the valves. The intake valves and seats all looked good. This is the first exhaust valve I've done and there's discoloration spots all over the lapped area. It doesn't look like pitting to me, but I'm not sure what to make of it. The seat has even color on the lapped area.

Is this pitting I'm seeing or just discoloration? If it's pitting, is it going to significantly impact performance? There's about 115k on the heads....

9004

[box]

From here it looks like that's pitted. If it were me, I'd be getting the heads and valves to a machine shop to have the seats and valves cut. While you're at it, check the valve guides for wear, they may be buggered too.

[BaadVR4]

From here it looks like that's pitted. If it were me, I'd be getting the heads and valves to a machine shop to have the seats and valves cut. While you're at it, check the valve guides for wear, they may be buggered too.

What he said. Times a bunch. Hand lapped valves/seats are short lived, even without your pitting issues on the exhaust side making it harder to get a good seal. Most machine shops standard valve job is 3 angle which will seal much better and last a lot longer than hand lapped.

[jeremy3s]

What he said. Times a bunch. Hand lapped valves/seats are short lived, even without your pitting issues on the exhaust side making it harder to get a good seal. Most machine shops standard valve job is 3 angle which will seal much better and last a lot longer than hand lapped.

My purpose with hand lapping isn't to do a valve grind or improve the seal, it's to check contact between the valves and seats. Essentially to make sure the valves aren't bent and everything is wearing evenly. I've encountered obviously pitted valves before and those are a no brainer. In this case, everything is concentric and wearing evenly.

These pits/discolorations are such that I can't really feel them with a dental pick. I realize that bringing them to a machine shop will make them perfect, but that doesn't necessarily mean I'll get enough benefit to make it worth the money.

Basically I'm just trying to figure out if this is normal. If so, it's going back together as is.

[RealMcCoy]

Yes it's pretty normal for a 100k+ mile motor... It's the beginning stages of some pitting. How many more miles do you want to get out of them?

What do the seats look like?

[jeremy3s]

^ The seats look great - no evidence of pitting at all. This is a project that got put off for years. Now I'm putting it back together to sell and get my money out of it. I want the buyer to get a good motor that will last for many miles, but only want to put as little money into it as I have to.

I'm considering bringing just the exhaust valves in to be ground. Is that reasonable?