On Tue, 2 Dec 1997 17:41:59 -0800 (PST) William Lewis
<wrlewis(at)ucdavis.edu> writes:
>If this is true, why have I been been dumping additives in my gas all
>these years? Jarrid, are you saying that these lead substitutes are
>not
>required? I would certainly like to quit dribbling this stuff down
>the
>side of my car trying to get it down the fill spout.
>
>Bill Lewis
>Series II (with brown gas filler pin striping)
The Rootes 4cyl engine, although very simple, used some of the
better materials compared with what British Leyland was producing.
The valves are hard, and chrome plated, the seats are some
hard alloy and the guides are some iron-bronze alloy.
The PCV equipped 1725 was certainly good enough to be a 100k
mile capable engine.
I've read quite a bit on gasoline additives and the whole lead debate,
and the general consensus is that the petro-chemical industry started
the rumors that older engines required leaded fuel because the
lead in the fuel was a magic lubricant.
The truth was that tetra-ethyl lead was a very inexpensive additive
that reduced the volatility of the gasoline "octane booster".
Any lubricative capabilities were likely incidental.
When the powers that be reckoned that lead was not good for you,
the Petro industry kicked and screamed that there was just no
replacement for the lead in the gas, and that engines would
come apart at the seems without it.
Older engines used older materials, which simply doesnt last
as long as the newer materials. Older engines may have used
soft steel valves, cast iron giudes, and no valve seats in a cast
iron head. These engines wear the valve train rapidly simply
beacuse the parts are softer than a hardened chrome plated
valve, and hardened steel seats. It really has nothing to do with
the fact that the lack of lead causes more valve or seat wear,
it has to do with the fact that 50s and 60s engines only went
50k miles before major internal work was needed.
One might make the argument that in the mid to late 70s, all the
car manufacturers changed thier materials to accomodate the lack
of lead in the gas.
Poppycock!
Materials science evolved a great deal in the 70s due to the influence
of materials developed and implimented in aerospace.
Hardened stainless steels replaced steel for wear resistance.
Todays fuels are pretty good, have plenty of neat additives
for all imaginable reasons. Along with the advances in motor oils
and the introduction of the PCV valve, todays 50s and 60s engines
can go double the miles they would have gone in their day.
Leaded fuel was removed from the market here in Ca, in 1991.
Since then, I have never used any "lead substitute" in any of
the 3 engines I have built and ran in the alpine. The original
1600 engine ran for 10k miles on 89 unleaded, before the
head gasket blew "head corrosion", and I head to have it
welded up.
When I took it apart, 20 years of lead deposits were caked on
the valves. I forgot how I got all the lead off, but I'm pretty sure
it contributed to the 20 or so IQ points I lost in that time frame.
Where was I going with this?
Oh yeah, the valves and seats still had plenty of margin, and all
I did was use grinding compound to clean up the sealing surfaces,
and slapped it back together.
10K miles later, I removed the 1600 "Smoking a little, but still
running strong", and put in another stock prepped 1725.
I have never known anyone to legitimately argue that lack of lead has
contributed to any undue wear on ANY engine. Just about all I have
heard is hear say, or such and such mechanic told me that......
I urge you to go through the paces like I did, and read up on this.
I dont recall the specific places to find the lit, but a good search
expression using the EXCITE search engine would be
"Gasoline FAQ" AND lead
Sorry so long, but I hope this puts some minds to some degree of
ease.
Flames?
Jarrid Gross
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