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Subject: TWL: Cold Weather Starting Diesel Engines
GYMKIDD319@XXX.XXX
Date: Thu Jan 02 2003 - 12:34:05 EST
Engineering Bulletin # 38 from Detroit Diesel has a few interesting factoids
regarding cold weather diesel engine starting as follows:
(Fuel, lube oil, coolant and engine compartment heaters are discussed with no
preference stated)
"...heat must be introduced ...for adequate oil flow through the engine at
start up..
As ambient temperatures drop, oil viscosity increases, batteries become less
efficient, engine friction increases and start cranking speed is reduced....
"..A 50% mix of ethyelene glycol protects to -33 degrees farenehit...
...a 63% solution to -75....
...a 100% solution freezes at -8 (Not a misprint!!) ....
...A solution containing MORE THAN 60% ethyelene glycol is NOT recommended...
"..Ether should only be used in properly installed ether starting systems.."
A graph shows that for a fully charged (specific gravity 1260) battery
cranking power is only 40% of total at zero degrees farenheit relative to
100% at 80 degrees...and is only 20% at zero degrees if 50% charged (1210
specific gravity).
Personal comments:
(1) For those of you occasionally using ether, crank the engine briefly first
(to warm the cylinders a bit) , then the shortest possible spray of ethers is
recommended ....less is better...when cranking again. Better to have to spray
and crank a second or third time rather than get too explosive an ether
injection and risk serious damage..
(2) Common sense suggests that engine compartment heating covers the most
bases but requires adequate timeelapse for the engine to warm to ambient.
Direct engine heaters (coolant or lube oil) probably provide faster heating
but not as extensive engine warming.
regards,
Rob Brueckner
Hatteras Yachtfish
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