My personal experience, on street cars (Mini's and MGB) is that I've had no
failures as a result of unleaded gas. No extreme valve seat wear. We've
had unleaded gas for a hell of a long time (a decade or more), and the MGB
is still waiting for it's first valve job. The answer, I've been told, is
that the cast iron valve seats work harden to a sufficient degree to resist
the erosion due to lack of lead to lubricate. It's very easy to put
hardened exhaust seats in if you're worried - but that's also the cure if
you have a problem so I've decided to wait until the problem arises rather
than prejudging the decision.
On race cars, the unleaded gas offers a different problem. The issue isn't
valve seat wear - you tend to re-do valve seats pretty often for other
reasons. But unleaded race gas, when used in high compression engines,
seems to be trickier to setup for, and several engines have been lost on
the dyno, etc. due to pre-ignition. Plus the stuff they put in unleaded
race gas is amazingly awful - if I'm following a car running the stuff on
the track my eyes literally water from the fumes! Solids can precitipate
out of solution if exposed to sunlight, etc. One brand apparently (rumour
here) doesn't even legally qualify as gasoline - not enough gas in it!
After the first six months or so, a decade ago, I stopped using lead
substitute and have never re-started as I never had a problem.
Cheers, Brian
At 06:38 AM 11/10/1999 -0500, you wrote:
>Now the European Gov has seen the light and decided to poison us all with
>Benzine instead of lead, in the UK we no longer have a sourse of Leaded
>Petrol.
>
>Whilst Lead Replacement petrol will (probably) cope with the stresses of
>ordinary motoring in the UK, does anyone out there have any experience of
>"hard motoring" using unleaded on engines designed for lead. By hard
>motoring I mean racing/fast road cruising at engine speeds of 4500rpm
>plus.
>
>The questions that I (and many others) would like answers to include
>1. Which adddatives are people using abroad.
>2. At what doesage rates
>3. Does anyone have any experience of teh Redline addative?
>
>If you have any input and would like to send replies to me, I will collate
>them and reply to the list
>
>thanks
>
>Geraint Owen
Brian Evans
Director, Global Sales
UUNET, An MCI WorldCom Company
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