Valve stem seats
I have a 3.2 ltr engine in my 911 and was going to
do the valve seats , do you need to remove the
heads or can you do them in place
no..just take out a spark plug put air nozzle make sure it doesn't lose pressure and/or suction..and replace..air will hold valve in place as long as there is pressure and solid flow of air to cylinder..
sorry that was for valve stem seals..i don't know any other way..if you do it on car you might nick the head and make it worse.which would lead to leaking valves and eventually head replacement..
So your basically talking about a valve job, yes the heads will have to come off, you may not have to replace the seats if they aren't burned, but you won't know that until you get it torn down.
Tennisshoes is correct, the heads must come off. The seats seldom require replacing unless you've got 400k + miles on them. So more than likely you'll need a valve job.
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