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Strange "dotted" pattern on valve seats and faces

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Old 05-02-2013 | 06:08 PM
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Default Strange "dotted" pattern on valve seats and faces

We were going to install better springs / retainers along with inconel valves in my GM heads, and this is what 5 out of 8 intake valves looked like after 30 hours. The engine builder who took them apart said he has never seen anything like this in 40+ years of building engines. It almost looks like the valve was only sealing in spots on the face. Funny thing was, engine was running fine, and compression check showed 185+ PSI on every cylinder. One thing to note - valve tips all had lines on them where the rocker arm roller tip was beginning to wear into the stems - they were not rotating in the guides.

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Has anyone ever seen anything like this? If so, what was the cause?
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Old 05-02-2013 | 06:16 PM
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I have seen that before its usually from who ever faced the valves had a lot of chatter When they were grinding them. They needed to face the stone and regrind the valve. Titanium valves do that a lot when facing them if the stone gets loaded up!!!
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Old 05-02-2013 | 06:45 PM
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Originally Posted by IRWIN
I have seen that before its usually from who ever faced the valves had a lot of chatter When they were grinding them. They needed to face the stone and regrind the valve. Titanium valves do that a lot when facing them if the stone gets loaded up!!!
So basically they botched the valve job? Hmmmm.
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Old 05-02-2013 | 06:54 PM
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I have also seen that. Agree with cutter chatter.

Jeff
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Old 05-02-2013 | 07:00 PM
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Not pointing fingers but lets just say the valves were not faced correctly!!! But it's a very easy fix. Have the seats cut and valves faced by a reputable shop and you will be good to go!!!
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Old 05-02-2013 | 07:12 PM
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Agree, poor cut and appears no rotation.
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Old 05-02-2013 | 08:01 PM
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Re-lap the valves, you`ll be fine.
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