Re: Valve Spring inserts

[EldonMcf@domain.elided]

Tom,

   From everything I have been able to find on this, the 304A is the only "A" 
engine that did not have a hardened seat for the exhaust valve.  I'm not sure 
if any of the small V engines had seats for the intake valves, they are shown 
in the parts books for Scouts, and also for trucks, but that could just be 
available to be used for repairing a head that has alot of wear.  I have to 
admit that I only have a few gas engines laying around here, and none have 
intake seat inserts wheather they are "A" engines or not.

    Some of the larger truck engines ( MV-404 & 446) use hardened seats for 
the exhaust only as well.  6.9L & 7.3L Diesel engines have a hardened seat 
for the exhaust, and have the intake seat area in the head induction hardened.


Eldon


In a message dated 4/16/99 2:48:45 PM Central Daylight Time, 
tjhemh@domain.elided writes:

> Eldon:
>  
>  Your belief in differnces between "regular" and "A" engines makes sense.
>  I've often heard that the "A"s dropped the stellite valve seat inserts
>  (sometimes it's said, only on the intakes and not the "hotter" exhaust
>  valve seats). But, this seemed contradictory for two reasons. Everyone else
>  was going to hardened valve seats at the time the "A"s came out, due to
>  reductions, and eventual elimination of, lead in gasoline. And two, I have
>  never heard that IH engines after a certain year weren't long lived. I've
>  heard of '76s with 300,000 miles and the heads had never been off the
>  block. My thought was if the valves were sealing that well for that long,
>  they used damn good valves and had hardened seats or  inserts.
>  
>  One of these days I'll pull the original heads of my '76 with 304A and see
>  what's what.
>  
>  Tom H.