----- Original Message -----
From: "tonygull" <tonygull@ozemail.com.au>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Tuesday, February 20, 2001 9:30 PM
Subject: [MV] CCKW stuff various..support for"cop"
> Hi List.
>
> First I would like to make an exception to my usual posting policy, which
is
> "only tech posts"
> to commend the bravery of the fellow that is
> a "Law enforcement officer"...you are a brave man!
>
I'll second that.
> Also i wish to state thankyou for freely giving info
> about road regs in USA..i live in Oz, so they dont affect me. I see u are
> coming under some attack.
>
They don't affect me either in the UK but interesting nonetheless. However
in this area the term UNITED with States seems to be a misnomer, perhaps a
delegation to Brussels to see how the EU are handling harmonisation for the
United States of Europe would be educational. . . . . . . . . .
> Re the 70-80 Octane fuel recipe...I got replies but none were conclusve.
> Dr Deuce came closest by infering HO fuel will cause trouble. So what are
> people running in there WW2 engines?
>
> I dont want to detonate my excellent 270 by running 92 Octane.
>
You cannot damage the engine by using a higher octane than is needed, you
just do not realise all the _potential_ power.
Octane ratings tell you very little about how the fuel actually performs,
all it means is that in the single cylinder, variable compression,
laboratory test engine (CFR engine) that bears little or no resemblance to
any automotive engine then a mixture of 92% n-octane and 8% n-heptane (a
fuel with almost zero octane rating) knocks at the same compression level as
the sample pump fuel.
What it doesn't tell you is the make up of aromatics and lead (if used) that
contribute to this octane rating, these things can have a drastic effect on
the real engine.
Almost invariably horror stories of damaged engines are incorrectly
attributed to octane ratings, high octane unleaded being used in an engine
that must have a valve seat lubricator, without a current, proven lead
substitute being added or, more obtusely and a documented WWII occurrence,
high lead (so high octane) fuels being used in MVs causing corrosion of the
valve stem and valve failure. In this instance the octane rating is always
blamed but has nothing to do with it at all, the seats are fine getting high
doses of melted lead salts but the stems, not being of a compatible steel
alloy like 21-4N steels, just corrode away fast and loose their heads with
drastic results.
I would advise against using paraffin (kerosene)(depending on continent) as
an octane reducer, it will not volatilise and will simply wash the oil off
the cylinder walls and then contaminate the lube oil, better to use a
heptane fraction which is a cheap industrial solvent very similar to
unleaded petrol (gas) and has an octane rating of about 10, one pint to a
gallon of 95 octane fuel will reduce it to 85 octane but its not really
needed except in special cases like pre-war, air cooled, side-valve (L head)
motor cycle engines.
If you need a lead substitute additive for exhaust valve seat protection
(note, up to a nominal 3000 rpm lead is never necessary) do choose
carefully, many products are around that contain manganese. These are very
effective at lubricating the valve seats but are unstable and form a filter
blocking sludge. Soluble iron such as ferrocene is better than lead for
seat protection but forms red iron oxide, otherwise known as Jeweller's
Rouge which is decidedly unfriendly for the bores and pistons.
Bear in mind that unleaded of today, compared with early WWII unleaded, has
the benefit of some 60 years of R&D, the lead-free octane improvers
currently widely used in pump fuel and advanced refining processes now leave
no combustion residues and so the valves have an easier life anyway.
It was commonplace to de-carbonise/valve grind engines pre and post war
every few thousand miles both to remove the deposits built up owing to poor
refining and catch seat recession before it became a problem, this is now
unnecessary.
>
> I did obtain "First Blood" ie Rambo, good film. Also saw "SAving Pt Ryan'
> sat thru the whole thing and only saw Jimmys a few times.
>
However, after all the hype of accuracy and attention to detail that was
attendant to Saving Ryan's Privates, the use of a Morris-Commercial MRA 1 of
the late fifties within the first 15 mins rather blew it for us. Russian
outfits faked to purport to be R75's further added to the problem and
especially galling as it is confirmed that real R75's (5 off) were to hand
off-shot. It was expected that the Tigers couldn't possibly be the real
things but perhaps a bit more credible if the fake plate bodywork had been
attached backwards so at least the driving sprockets would have been
correctly in the front.
P51Ds exploding these Tigers with 0.5" seems a bit far-fetched, more likely
that flying Typhoons (rocket firing) are totally unobtainable (although we
keenly await Kermit Weeks efforts) and digitised images would have been
prohibitive.
Richard
Southampton - England
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