I have used Marvel Mystery Oil as a gas additive since lead was taken out. I
have put many miles on old British engines during this period without any
valve problems. However this is not based upon any scientific evidence. I
started using it because that it what the older fellows in the MG car clubs
were suggesting at the time and I have continued doing it ever since. The
theory is that this lightweight oil helps to lube the valves in place of the
lead. I put in 4 ounces per 10 gallons of fuel. It is cheap and doesn't
appear to hurt anything.
Phil Roettjer
67 Morgan +4
67 MGB
Previous cars: 73 MGB, 54 MGTF and 70 Jag E-type (all run on non-leaded
fuel)
> -----Original Message-----
> From: Brian Evans [SMTP:brian@uunet.ca]
> Sent: Wednesday, November 10, 1999 9:18 AM
> To: Dr G W Owen
> Cc: vintage-race@autox.team.net
> Subject: Re: Unleaded and all that
>
> 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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