Recently I went to look at a worked set of 906 heads for sale. Some mild porting, larger valves, bronze guides, springs, etc and claimed to have less than 1000 miles on them. They did look to be low mile units and had been stored well.
Just about when I was going to reach for my wallet I noticed the tip of one valve had a slight "U' worn into the center of the tip. You could feel it with a finger nail and there was a bit of discoloration in the U area. Looking further I found another that had the same problem but also exhibited a second wear pattern about 40 degrees turned from the first pattern. Checking the other head I found yet a third one with the same problem developing, only less noticeable.
The seller seemed genuinely surprised when I pointed these areas out to him. He asked what I'd pay for them and I made an offer, considering I was going to have to disassemble them, possibly be replacing at least 3 valves and wondering about the valve guides. I've always been under the impression valves rotate somewhat as an engine is running. I wondered if a valve guide problem could interfere with this movement and cause this sort of wear. Anyway, my offer was not accepted and we parted ways on good terms. Nice guy and I don't think he was trying to pull anything.
I continue to wonder what was going on with these so thought I'd put it out here and see what your thoughts are. Thanks in advance!
Just about when I was going to reach for my wallet I noticed the tip of one valve had a slight "U' worn into the center of the tip. You could feel it with a finger nail and there was a bit of discoloration in the U area. Looking further I found another that had the same problem but also exhibited a second wear pattern about 40 degrees turned from the first pattern. Checking the other head I found yet a third one with the same problem developing, only less noticeable.
The seller seemed genuinely surprised when I pointed these areas out to him. He asked what I'd pay for them and I made an offer, considering I was going to have to disassemble them, possibly be replacing at least 3 valves and wondering about the valve guides. I've always been under the impression valves rotate somewhat as an engine is running. I wondered if a valve guide problem could interfere with this movement and cause this sort of wear. Anyway, my offer was not accepted and we parted ways on good terms. Nice guy and I don't think he was trying to pull anything.
I continue to wonder what was going on with these so thought I'd put it out here and see what your thoughts are. Thanks in advance!