Two observations - first, I have been a professional mechanic, specializing
in repairing British sports cars, since 1975. In those 26 years, I have
encountered many instances where valves have burned and heads have been
damaged as a result of using unleaded fuel in engines not designed for them.
Second, typically it isn't "hard" driving that causes valves to burn. Rather
travelling at steady speeds for hours at a time is more often the cause.
Example: I rebuilt a TC engine for a customer who then drove from Malibu to
Vail, Colorado and back, in company with a group of enthusiasts attending a
GoF West event. When she arrived home, the car was running rough. A
compression test revealed no compression in one cylinder. Removal of the
head showed an exhaust valve with a pie-shaped section burned away! This
just 3,000 miles or so after a professional rebuild. Now, you have to know
that this was in 1978, when the need for modifications to cope with unleaded
fuel was just becoming understood. We rebuilt the head again (under
warranty, of course) but this time we fitted hardened exhaust seats. When I
last heard from this customer, the car was still running beautifully, and it
has been on many more long trips.
That was twenty-odd years ago. Most engines we work on these days have
already been fitted with hard seats, as the technology is certainly nothing
new. This may account for why people who have not asked their machine shops
to perform this work have had no problems with valve seat recession - either
the hard seats were already there, or the machine shop installed them as a
matter of course and didn't draw attention to that fact. As I said in my
earlier post, it's not a particularly expensive procedure.
I don't buy name-brand products because I'm influenced by extensive
advertising. In fact, I resent those products because I believe the prices
could be lower if they didn't spend so much on advertising! But, then, I'm
an anachronistic old fogey (according to some of my friends!) - although I
do believe that if there's a simple fix for a potential problem, it's worth
taking. That's why I have a flu shot every year, and have hard exhaust seats
fitted in all the engines I rebuild.
Happy New Year to All!
British Sportscar Center
(Who, by the way, most definitely was not on the "Awards Committee". That
post was inappropriate and in extremely bad taste, IMNSHO.)
From: Barrie Robinson <firstname.lastname@example.org>
To: Rocky Frisco <email@example.com>; firstname.lastname@example.org
Date: Monday, December 31, 2001 11:37 AM
Subject: Re: Blown Head gasket
>I ran an MGB GT for 8 years here in Canada in summer and winter and I do
>not drive "soft" but neither do I thrash the engine. The car's body
>collapsed under the weight of rust but the engine went into my friends car
>and is still smooth, lusty and pulls hard (sound like a girlfriend I
>had). It never saw leaded fuel! I then tested Shell Canada unleaded
>over a years driving an Austin Healey - they paid for everything. The
>engine was measured with a special jig made by Shell to determine wear -
>result? no signs of valve seat recession. I believe that hardened seats
>are great but not always required - unless you intend to thrash the engine
>(in which case something else will give too). If you look around you will
>see the marketing of many not really needed products from Nike, Coca Cola,
>Gap, MacDonalds, Disney etc so why should fuel additive companies be any
>different by promoting a false image that enhances their sales. - CONSUME
>DUMMY - it makes me rich!
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