Hi Guys,
Well here goes. . . . . . . .
>I you use your Mil-Veh as a daily driver, I think you should go
>for the hardened valve seat inserts.... It's called peace of
>mind...
>
Couldn't disagree with that.
>I'd love to see other opinions on this... especially on the
>prognosis on engine life expectancy if it is run exclusively and
>daily with unleaded fuel.
>
This is what I know having done a bit of research owing to the sudden anxiety in
our local MVT group with the now immediate spectre of leaded petrol disappearing
from the UK on 1 Jan 2000.
We ended up talking to the chief scientist at the Associated Octal Company,
these are the people that make the TEL (Tetra Ethyl Lead) for leaded fuel and
originally were the Associated Ethyl Co., who employed the somewhat important
but unknown historical figure of F R Banks; this guy formulated the fuel for the
winning S6 Schnieder seaplane and we know where that led to. Incidentally this
was a quite strange brew of Romanian petrol, acetone and gobs of TEL.
As engines became more powerful leaded fuels were seen as the answer to
compression ratio hikes, the problem of valve seat recession was thus masked and
nobody went looking for the problem that didn't exist, in fact land based
cooking engines of the time were slow revving and usually side-valves (flat
heads) both factors help greatly with seat wear. For seat protection the level
of TEL needed is tiny and at least 1/4 of that currently in present already low
lead pump fuel here, apparently the effects of the lead also take some time to
dissipate, we were advised some 500 miles from the last use of leaded fuel is
needed before the effects disappear.
It was confirmed that engines not exceeding a _nominal_ 3000 RPM don't really
need lead anyway but this is a rule of thumb figure and dependant on the actual
motor in question the spread could be typically 2800 for some and 3200 say for
others. The flat head configuration also helps in that the valve, and seat
especially, is given a much easier life in the well cooled mass of the block;
this is an actual design feature of the post-war RR B Range engines with IOE
layouts you find in the Champ, Ferret, Saracen/Saladin, Stalwart, 432 etc., to
obtain the specified continuous output with engine longevity.
We were told that the people in real trouble are the OHV/OHC 50's/60's racers
with highly modified and high revving domestic engines requiring both an octane
boost and seat lubrication, most W.W.II mil engines are real chuggers by
comparison and would actually be happier on lower grade fuel than that actually
available, some people here are adding a modicum of kerosene to alleviate vapour
lock and carb icing problems with the present high volatility pump fuel.
There are certainly references in original W.W.II manuals about the use of
leaded fuels and the different presentation of the engine internals on
strip-down implying the normal fuel would be unleaded, we have a regular
contributor to the national MVT magazine who has toured Europe in I believe a
Dodge of some sort keeping detailed records and using unleaded fuel only over
some 30,000 miles +, with no adverse effects.
Hitching a rev counter temporarily onto some W.W.II vehicles does indeed show
that 3000 RPM is usually felt as thrashing them within an inch of their lives
and if attainable it is unnecessary, the CMP F15 is specified as 51 MPH max
which equates to a tad over 3000 RPM however in the real world 40ish is plenty
without being brutal and equates to 2750 as does apparently the "felt to be
really revving it" gear change points.
The Federation of Historic Vehicles here has taken up the case on behalf of the
many groups and clubs to arrive at a lab standard test operated by Ass. Oct. Co.
to prove the efficacy of the many, and often expensive, additives now flooding
onto our market. The test engine is actually a BMC A series (Morris Minors ,
Minis etc.) as this is the worst example of unleaded pocketing you can find,
reputedly 1 thou/5 mins at 60MPH equivalent revs.
It is no surprise that a large number declined to submit samples and so far four
products have been proven, AOC's "Valvemaster" being one of them, all of the
in-line magic boxes and pills in tank things had no measurable effect. (Except
on the makers bank balance that is).
It is apparent cost wise that things are confusing, the expensive additives
being added at a tiny rate whilst the apparently cheap ones treat barely 5
gallons, a careful sum on cost per gallon is necessary.
Now, no one is saying just dump unleaded in your prize and joy no matter what,
but it is worth a bit of specific investigation and might not be as bad as
everyone thinks.
Please allow me a little digression, recently in the UK a very important
artefact was unearthed in the shape of extensive pre-Roman (Romans had lead
pipes), human remains, published lab tests showed the lead intake was identical
to us leaded era 20th century people, then it went quiet, very, very quiet. . .
. . . . . . . .
Richard
(Southampton UK)
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