Lawrie Alexander wrote:
>
> Maynard, Maynard, Maynard............
>
> So much good advice from your keyboard this year, and then you wait till the
> very end to post this! Empirical tests have proven that hard seats prevent
> valve seat recession. Just about every qualified mechanic who has worked on
> cars that were not originally fitted with hard seats knows that they are
> necessary to prevent valve seat recession. The additional cost during a
> valve job is so small that, unless the finished rebuild is going to sit in a
> trailer queen that never gets used, it's truly false economy not to have it
> done.
>
> I hate to close the year on a critical note, but hardened exhaust valve
> seats are a must when doing a valve job - if they have not already been
> fitted during prior work on the engine. You may choose, of course, for
> whatever reason, to find them unnecessary, but please don't try and convince
> other neophytes to the world of engine rebuilds that your choice is the most
> sensible!
I've been building racing engines since 1964 and I'm beginning to
get an opinion on the hardened seats question. The present engine in
my Cooper S is a 1967 Cooper S Engine that came out of a car that
raced at Sebring way over 30 years ago. I installed an APT 286
scatter cam when I built it. It has a very free-flow breathing
system with a single 1.75" HIF SU on it and an LCB exhaust system
with a free-flow silencer. I use a 3:44 diff and standard 4-synchro
trans. That puts me over 4k rpm when cruising on the motorway. Since
the original build, I've done an 800+ mile round trip from Tulsa to
Saint Louis and back, as well as many 200 mile round trips. I drive
fast and hard because it's fun (and I have four spare power units
stored for emergencies).
I've had the head off three times for various reasons since then and
have seen no evidence at all of seat recession or valve wear even
though we haven't had leaded fuel here for decades. I have spare
heads in the garage, so my plan has been to wait until I see damage
beginning to manifest from the crap fuel, then to have the hardened
seats installed. So far there has been no damage, so no need.
Compression remains very good and very even.
I have also heard horror stories about recession and wear using
unleaded, mostly from friends in the UK, I wonder if the petrol
formulations are quite different.
The Victor MGB-TF is up on blocks waiting for some relatively warm
weather to get his new clutch TOB installed. One of these days I
will be building the spare B engine up to high performance specs to
install in the Victor, so I'm very interested in this discussion.
-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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