13.6 is leaner than 12.5.

Looks lean

Running that rich and n/a your cylinders should be black. Yet the chamber looks steam cleaned with no carbon, unless that is just the pic. How does the piston top and edges look?

Here's a pic of the piston from that cylinder.

tj,

That is what you call a "burnt" valve. If it only is the one valve and it has 100 hrs since a valve job, I would bet that either water has been getting into that cylinder, or the valve job was not done properly, causing the valve not to seat properly in the places where it is burnt. Without having the head or valve to look at, its hard to speculate about the cause.

Bill Koustenis
Advanced Automotive Machine
Waldor fMd

I'am still wanting to see what he says about the valve seat, I told him that the valve looked like the valve was burnt in those areas shown, I would be willing to bet the seat is bad or the valve job is bad.

You also said 1:8 rockers. With that rocker the cam might not be letting the valve close all the way once the engine gets hot. You could have had it a little to tight giving the impresion of a bad valve seat. When valves do not close all the way, the heat from the valve can't dissipate into the seat. If it is not closing all the way, eventually during combustion, it could burn away part of the valve by allowing heat to pass by the valve.

But it still looks way to lean, or the timing is to far advanced. The rockersize increase can cause all of the above if not careful.

I am planning on tearing the heads down tonight and getting more pictures. If anyone would like to see larger pics of the valve, send me your email and I'll send them to you. With a larger pic, the missing pieces look to have broken off, not burned/melted. Also, you can see a crack coming off one of the broken areas. Thanks for all the help so far.

looks like heat got them to me...Rob

They are burnt, take my word for it.

Also, pictures might not show anything. You need to have a good machine shop check the valve job for concentricity and proper contact width.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md