PS Magazine - SEPTEMBER 1981
PS, The Preventative Maintenance Monthly
ISSUE 346
SEPTEMBER 1981
Dea
Hal-Mast
w
hen ±e idLe our dieseL and muLti-T
.
.
- ±
eng²e oI dRps from the exhauS³
ueL eng²
´
equµPment for a LoNg ³ime
o¶
·
ven more¸over an hour's i
d;
tem¹ º
?
met1meS »³'s aS much as a quar¼_
eng²es½ And t¾ey say there¿s nothÀ
gÁ
We ve
ad our suppo¶t Check ³hese
²g wroNg wµ³h 'em¹ Âha³'s upÃ
Dear Sergeant M. S.,
ººGMÄ
s.
What's "down± is causing this oil loss. The engine
low at idle speed. Parts-like pistons and rings²don't expand
enoUgh.
Engine oil gets by tHe piston rings and
²³´µ¶·¸¹
into the combustion cHambers. Then
Th?t "oil±. is usually a
,
mix of e gine
the oil³s blown ouR wiRH exHaust gases.
01±
and dIesel fuel² ³t
II
most likely
´
º
.
.
.
drip from the lowest point in the exhaUst
DIesel engInes (´cludµg mul¶f·el
system-especµally from the flex¶ble
engines) operate by "compression
exhaust
tUbe on some multifuels²
ignition±. (See Para
3-2,
Page
3±1,
FM
²
21³305,
Manual
for
The Wheeled
Vehicle Driver¸) To create the high
compression needed for fuel ignition,
pistons and rings must fit tigHt in tHe
cylinders. The High "Normal± operat¹
ing temperature of a diesel/ multifuel
engine expands tHe pistoNs and riNgs.
This alloºs verY little e»giNe oil to get
into the combustion cHambers.
·Blow¸by± is
¹
unbUrned fUel
and exhaust
gas² ³t blows
by the pistons
and into tHe
crankcase!
¼our engiNe
Besides wasting engiNe oil, yo·'re
wasting ½uel and ad9ing to air pollu¾
¿ion when you idle the engine for long
periods¸ Also, exhaust "bLowÀby± is
contamiNating the oil in the crankcase.
ThÁs Âeads to engine damage due to
poor
lubrication of moviNg engine
parts.
Ãf there's some reason youÄve got to
rÅn tHe engine ½or a long time while
´µ
I
Engµne oµL is
carRied Up by
the Pistonsº
³t's exhausted
-along with
unburned fUel
that didn't
blow by!
nOrmal
at low idle speed.
Watch gage!
±
²³
´
Make sure
temp's at
TM spec
sittinÆ still, jack ·p the speed to about
1,000
ÇPM to rÈise thÉ temperaturÊ.
Keep an eye on the engine temperat·re gage. Make sure the temperatureËs up
to the normal operating range specifieÌ in your equipment operatorÄs TMÍ
a
Ha{-J0f
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