General rule of thumb for professional truck drivers is idle for 5 minutes
before shutting down. This allows turbo impeller to slow down the most and
cools the bearings down for as no damage engine stop. Five minutes saves
fuel if your going to be stationary for a hour. Average M-35A2 will pump up
air from zero in less than 2 minutes to be ready to roll. $1.59.9 here in
NH!! And rising!!!
James Shanks
n1vbn@bit-net.com
----- Original Message -----
From: <DDoyle9570@aol.com>
To: Military Vehicles Mailing List <mil-veh@mil-veh.org>
Sent: Thursday, April 19, 2001 7:39 AM
Subject: Re: [MV] Another M35 Starter Question
> In a message dated 4/18/01 11:22:41 AM Central Standard Time,
> kbernste@us.ibm.com writes:
>
> << A stranger (jealous one, I think) warned me while I was
> fueling up the other day that I only had a very limited number of starts
I
> should
> expect out of a deuce's starter, and that I should let it run
> all day rather than shut it off if I'm starting up later.
>
> Clearly there is a lifetime associated with any
> electric device, but critically low enough to worry about this?
> I suspect the old geez just wanted a little authority,
> but I've never heard this before - comments?
> >>
>
> More than one of the many TM's I have around here say that the truck
> shouldn't be shut off for short breaks (I seem to remember the definition
of
> short as about an hour), but rather should be left running.
> I doubt it has anything to do with the starter motor. My list of suspects
> for this reasoning are:
> 1 Turbo bearings. It is important that an adequate cool-down period be
> allowed for these. Very hard on them to just pull up and shut engine down.
> The oil just cooks them.
> 2 relationship between engine operating temperature and horsepower
available.
> Cold engine in loaded truck equals poor acceleration/grade capacity.
> 3 tendency of engine temp to rise, immediately after shut down.
> 4 delay restarting travel to (possibly) allow air pressure to build back
up
> (depending on length of stop and condition of vehicle air system)
>
> The engine at idle burns relatively little fuel. I can't immediately lay
my
> hand on the exact number. But a LDT-465 at rated power & speed (130 hp @
> 2600 rpm) has a maximum fuel consumption of 64 lb per hour. (Source TM
> 9-2815-210-34)
> At idle the injection pump is delivering a little less than half as much
fuel
> at it idle as it does at fuel load (Source TM 9-2910-226-34).
> I don't know the density of diesel fuel, I'm guessing about 8 lbs per
gallon,
> which means at idle the truck would burn about 4 gallons per hour. I
would
> imagine the federal government buys diesel in the 30 cent per gallon price
> range (remember, no taxes for them, plus LARGE volume discount). So it
costs
> the taxpayers a buck 20 for the truck to idle that hour. MUCH cheaper than
> turbo bearings, less fuel than it'd take a cold engine to struggle with
load,
> etc.
>
> Hope this helps,
> David
>
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This archive was generated by hypermail 2b29 : Tue May 01 2001 - 07:42:41 PDT