John McMaster said:
Following the thread on lead and fuel pumps, I thought the problem
with the PI cars was in the metering unit and not the pump. Egil
is
right in that the pump doesn't need lead to lubricate it but the
metering unit does. With the close tolerances of the shuttle, the
lead
provides a lubricant and increases the life of the unit. Without
lead,
I'm not sure if there is sufficient lubricant for the unit.
John,
I'm no expert in this area but like you I've followed what has been said
in this list and also read whatever else I've been able to find on the
subject. Everyone agrees that lead is a lubricant after leaded fuel
combustion and therefore a lack of it has an impact on exhaust valves
and seats, but is there any clear evidence to prove that lead in leaded
fuel it is a lubricant *before* combustion? I have read differing
opinions on this. Perhaps some of the chemical experts on the list can
comment?
Don Guthrie
don.guthrie@ho.tradenz.govt.nz
'74 TR6 PI (150bhp)
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