Denise Thorpe wrote:
>
> Me too. I've never put hardened valve seats into any of my MG's and I've
> never seen any valve recession. My first '67B has 300K miles on it, 200K
> put on by me since I bought it in '79 (multiple short blocks, same pre-smog
> head). I was also waiting for evidence before I cut into the head, but I
> haven't seen any. However, I have seen the mess that results when a
> hardened valve seat comes loose. Not pretty!
>
> But then, there's the argument that older heads that were used when gas had
> lead in it are already impregnated with lead and therefore don't wear.
> That's possible too. If I'm ever so far ahead on restorations that I get
> around to putting a cross-flow head on a '67B (which will necessarily be
> new and not lead-soaked) I plan to pull the thing off after a few thousand
> miles and look for wear. Or do they come with hardened seats?
No idea. The discussion has me pondering.
I'm coming to this tentative conclusion: Valves and seats can
sometimes be as individual and different as people or weasels or
snowflakes. Remember the (apparently true) story about thousands of
racing crankshafts that accidentally went into plodgy Austin
Americas with standard transmissions for export to the USA? Most of
these are autos (crap), but many of the standard cars can be bought
for the value of the starter motor and they might well have an ENB40
nitrided and balanced crankshaft, which is worth much more now than
the original selling price of the cars.
I'll bet both hardened and standard old fashioned valve seats vary
wildly in their characteristics, maybe even depending on what the
foreman had for lunch, so everybody is speaking from wisdom and
experience with seats, but the valve seats were seriously different.
In any case, it would appear that the safest thing would be to have
the new ones installed really well by a qualified shop the next time
it's easy. On the other hand, it hurts me to fix something that
doesn't seem to be broken in any way. I'm certainly open to any
further relevant information in the mean time. ;)
-Rock http://www.rocky-frisco.com
--
Red Dirt Rangers (Rocky on piano): http://www.reddirtrangers.com
JJ Cale Live (w/Rocky): http://www.rocky-frisco.com/calelive.htm
The Luggage Fan Club: http://groups.yahoo.com/group/luggage-fans
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