Author Topic: Hardened seats  (Read 119 times)

maxi426

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Hardened seats
« on: December 06, 2018, 06:11:30 AM »
I'm going to have a set of early 350 heads done to put on a 403. One local shop is really recommending hardened valve seats. The other, not so much. It's my understanding that 7a heads already have the seats hardened. If this is correct information, can the valve size be increased to big block size and still have enough hardened seat left to be effective? I don't have cores yet, so I'll look for "7a"s. if this will work. The car will maybe see 2000 miles per year. Should I even worry?

Aus78Formula

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Re: Hardened seats
« Reply #1 on: December 06, 2018, 04:38:49 PM »
See what cores you find then decide what they need doing.

langss

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Re: Hardened seats
« Reply #2 on: December 06, 2018, 05:03:20 PM »
Here is a link that explains Valve Seat Recession https://oldschool.co.nz/index.php?/topic/20751-valve-seat-recession-explained/
And Here https://www.enginebuildermag.com/1997/02/getting-a-good-seat-the-growth-in-the-valve-seat-insert-market/
My personal experience is without the Hardened Seats, Valve Seat Recession is  not an issue on a car that never see's any abuse. But if your planning on running it hard....Have the seats installed.

maxi426

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Re: Hardened seats
« Reply #3 on: December 06, 2018, 06:54:20 PM »
Is it a fact that the seats are already induction hardened on the 7a head?

olds403

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Re: Hardened seats
« Reply #4 on: December 07, 2018, 09:38:10 AM »
Once you do a valve job that hardened surface is gone.  I would not worry about it.
If you have to sleep better at night get seats pressed in.  No need to over think this.

Re: Hardened seats
« Reply #4 on: December 07, 2018, 09:38:10 AM »