[AT] [External] Re: Valve Seat Inserts

[Howard Pletcher]

IH truck gas engines also had quite hard heads without inserts, hard enough
that reportedly some shops thought there were already inserts in them when
they tried to work on them.  Few problems seem to have developed in the
years since lead was dropped.  I believe it is the material used in the
castings, not heat treating.  But these engines were designed for extended
use at wide open throttle in trucks like the Loadstar so they are not
stressed in smaller trucks like pickups and Scouts.

Different Divisions of IH, different foundries, different engineers.  But
perhaps they did talk to each other.

Howard

On Fri, Dec 4, 2020 at 1:59 PM Jim Becker <mr.jebecker at gmail.com> wrote:

> The only reference I found that directly addresses this is the I&T Shop
> Manual.  I presume it is accurate although it is not first-hand IH
> material.  According to it, the M, 6, and 9 series non-Diesels used inserts
> for the exhaust valve seats.  The H did not but the Super H and Super 4
> series did.  The Diesel M, 6, and 9 series did not use inserts.
>
> The higher compression of a Diesel translates into a higher temperature in
> the chamber prior to ignition.  I don’t know if that translates to higher
> temperature after ignition and completion of the power stroke.  I suspect
> not.  Diesel fuel itself isn’t that great of a lubricant but is a better
> one than gasoline.  That may make enough difference for IH to have decided
> to not use hardened inserts in Diesels.  Nothing in the above eliminates
> the possibility of hardening the seats that were ground into the Diesel
> heads.  IH was big on induction hardening and applied it to a lot of
> things.  I am not aware of them heat treating cast iron parts.
>
> Jim Becker
>
>
>
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