Author Topic: Valve Job with Hardened Seats?  (Read 2506 times)

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Offline '79 Blvd Bird

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Valve Job with Hardened Seats?
« on: May 11, 2006, 09:55:52 AM »
Back in my day when unleaded gas was introduced,  "NEW" engines came with hardened valve seats.  QUESTION: If I'm going to do a valve job, are there any precautions to take in GRINDING the HARDENED valve seats or do they not even need grinding because they are HARDENED?

I haven't built up a trust with any machine shop around here yet and don't want to be snookered.  Thanks for any info or experiences.

Offline hesster

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Valve Job with Hardened Seats?
« Reply #1 on: June 07, 2006, 12:11:23 PM »
There is no difference in the machining operation between heads with or without hardened seats.
If you are running the old heads w/o hardened seats you are OK on the street UNLESS you are modified for high performance with a non-stock cam.
What will happen is your valve seats will wear out more rapidly.  The lead in the old gas was essentially a lubricant.
In any event, if you are going to get a valve job on the older Hi-Po heads, I recommend you get hardened valcve seats installed and then get a valve job.
I did exactly this on my T/A - I run #12 heads fully ported with a HC-03 H/O cam (over .500 lift) and nitrous.  I will never have to worry about valve seat wear.