Jim---I agree with what you say, with the possible exception on what we
find on the back side of the valves. This heavy carbon caking that is
still present to some degree on the bottom of the valve stems is the
result of oil coming down the valve guides. Even with the no-lead gas
that most of us now use.
Tops of pistons and, to a lesser degree, some of the head cavities in
"used" engines are still found to have a carbon buildup, tho rarely
necessary to give reason for a tear-down.
The percentage of this caking found in engines that used the leaded
formulas I do not know.
It is true about the gasoline refining process. They ARE able to give us
a higher octane, comparable with the 100+ leaded we once enjoyed in
hotted-up motors. It is said that they can't get as many gallons of gas
out of a barrel of oil when they poduce the higher octane. When they do,
it costs an arm & leg for this stuff, but it is legal to pump right
into your tank.
The same debate is trying to be made for those companies selling
"hardened valve seats, for those engines using no-lead gasoline". I
never bought into this, since I've found no ill effects
with the integral seats and the absence of lead.
Dick
Jim wrote:
This very old issue of "lead" additives being crucial is a crock
designed to sell a product. If you want to see what lead does, look at
the valve stems of an old engine that was run for years on "leaded" gas.
You get a huge buildup of lead oxide on the back of the valve and stem,
enough such that the weight of the valve can actually increase by 50%!
The interior of the cylinders and face of the pistons get heavy loads of
lead. How do I know? I've pulled apart and rebuilt more than a few
Triumphs and other engines over the years. Old manuals (including the
TR-2 and -3 shop manual) actually recommended that you periodically
remove the head and clean these in order to prevent dieseling. Getting
this crap off the parts is a real PITA.
The adding of lead (tetra-ethyl lead) was to simply reduce the cost to
the oil refiners for the production of higher octane gas. They could
achieve exactly the same result by simply doing a better job of
refining. When I was a kid, Amoco sold ONLY unleaded gas. It cost a
couple of cents more per gallon, but was considered the best gas you
could buy. Bob Tullius, whom I at the time knew, said he would run
nothing but Amoco in any Triumph.
Cheers.
-----Original
Message-----
From:
owner-6pack@autox.team.net on behalf of Sally or Dick Taylor
Sent: Fri 5/13/2005 1:09 AM
To: 6pack@autox.team.net
Cc:
Subject: Re:.....lead
additives
Virginia---I can't think
of any reason for you to use any of these lead additives.
I've used the unleaded gas since 1989, with well over 100,000
miles since. No measureable valve recession has taken place,which is
what these products are supposed to protect the engine
against. Your engine should have the stellite valves, low
compression and mild valve springs. You can save your money!
Dick
Los Angeles
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