Date sent: Wed, 03 Nov 1999 00:05:51 -0700
From: "Michael D. Porter" <mporter@zianet.com>
Organization: Barely enough
To: "J.H. Roulleaux" <Jean.Rouleaux@skynet.be>
Copies to: "triumphs@autox.team.net" <triumphs@autox.team.net>,
CIS AMREIN <cisamrein@access.ch>
Subject: Re: TR6 PI and unleaded fuel
Send reply to: "Michael D. Porter" <mporter@zianet.com>
"J.H. Roulleaux" wrote:
> 2. the extremely small tolerances of the rotor assembly requires a
> certain degree of lubrication, this is provided by leaded petrol, but
> the different chemicals in unleaded do not guarantee a proper
> lubrication.
As others have suggested, not exactly true. Yes, the rotor requires some
lubrication, but that is accomplished by the fuel itself in concert with
another element, sulfur.
Note that mechanical (as opposed to electronic) diesel engines have for
years used shuttle-operated metering units very much like that used in
the Lucas PI system, at far higher operating pressures, without benefit
of lead additives. Sulfur represents about 1/4 to 1 percent of the total
by weight in most petroleum fuels, depending upon source, and that
amount of sulfur serves quite adequately as a lubricant for metering
unit parts. Sulfur is almost always present in refined fuels to some
degree, so it's not as if one must add it.
Cheers.
Hi Michael,
I did not say that lead in leaded petrol is providing the lubrication in
the Lucas metering units, this was said by Lucas themself, but in
the mean time it is known that this is not true. I'm a member of 3
rather large TR clubs with together about 8000 TRs and I drive TRs
since 1963. I have studied hunderds of articles about lead free fuel
and PI TRs and I know that there are more opinions about this
subject than there are TR drivers. If any body at this time is still
asking questions about the subject I understand that he is a novice
in PI systems and I would not dare to suggest him to buy parts and
to venture into a rebuild of a metering unit, because he finally would
end up with a much higher bill.
You might know that some road testing has been done with lead
free fuel in Lucas metering units by continental clubs.The result
was that some units seized and others did not.The why could only
be declared by the difference in rotor tolerance in the metering unit.
So if you don't want to end up on a motorway at night 500 miles
from home with a seized metering unit buy a safe one that is well
calibrated from a reliable source.
Jean R
70 TR6 PI ( since april on electronic fuel injection and ignition
calibrated via lamda sensor and lap-top)
60 TR3A
|