Re: IML: hardened seats and such

[sosmi@xxxxxxxxxxx]

In response to larger valves: Changing to larger valves in the early head, won't matter much at all, as the valve size changed with the head casting, and port size. The larger valves came about for two major reasons,Performance, and then later, Emissions.No question, hardened valve seats are a must, at valve job time, but after that, I think that your  improvements become immeasurable. If the heads were bad enough, the valve job would certainly help performance, after bringing compression back to spec, and removing carbon deposits on valve stems, and combustion chambers. Ya'll have a nice day, Dave.

 

-------------- Original message --------------
From: "Frederick Joslin" <fljoslin@xxxxxxxx>

In addition to hardened seats I would strongly recommend going to the 1.74" exhaust valves from the 1.6". There was a reason that Mopar made this change to all of their Big Block heads.

I did this on a 1966 383 in a Newport. The hardened seats should be easier to find as should the valves and you will get improved performance.    

 

----- Original Message -----
From: "mike and linda sutton"
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: Re: IML: hardened seats and such
Date: Mon, 30 Oct 2006 21:18:51 -0800


I vote with the chorus here, do the hardened
seats and while theyre at it, if the guides are
at all suspicious, do the bronze wall guides
too. Avoid the temptation to knurlize the
existing guides and do it once, do it right.
Since the guide sets the center of the valve in
its place as well as pilots the seat cutting
operation theres no reason to have a valve stem
start wobbling in the guide a few thousand
miles later. I doubt even a purest of the
purists would complain about such an operation,
since its internal and not going to be noticed
at a car show. And it goes without saying that
the shop doing the work will set the valve
spring height, spring pressure and valve stem
height to the correct values as well. I had a
set of heads done this way in 1989 and they are
still performing strong today.

Mikey
62 Crown Coupe -----------------
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Fred Joslin