| Preface
In Part-IX of this 'series', I shared with you some thoughts real life
and experience about different kinds of problems one can run into while
maintaining one's Car.
Well, here's some more ..
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1)
How to check for a ‘slipping’ Clutch
Ever so often, one is confronted with an expensive proposition either
by one’s garage or the ‘FNM’ that one’s Clutch
needs overhauling, where as in reality it may not be so ! Here’s
what one can do to make sure that one is not being taken for a ‘ride’
:
If you have a Tacho on Dash, it's easy to double check this by getting
the Car into the 4th gear, say at 30 kph, note the Tacho reading and then
floor the gas pedal suddenly. If the clutch is slipping, then the engine
will revv-up disproportionately compared to the gain in the road speed
of the car.
In other words, if the Tacho showed, say, 1500 rpm in 4th gear at 30 kph,
then it should show ~ 3,000 rpm at 60 kph if the clutch is healthy and
not slipping. If it shows appreciably more than 3,000 rpm, then the clutch
is definitely slipping.
On the otherhand, if one doesn’t have a Tacho on the Dash, then
the way to check it out would be to park the car with the hand brake fully
engaged and then try to take off in the 1st gear ‘somewhat forcibly’.
If the clutch were to be healthy, the Car would tend to stall but if its
clutch is slipping it won't and instead, its engine would tend to revv-up.
2) Cold/Stalling Mpfi's
Although all Mpfi’s in good working order should get into ‘Auto-Choke’
mode when fired from cold/overnight park in the open, especially in north
India where temps can dip to < 5*C overnight during winters, people
some times experience morning starting troubles in such situations. The
following are the possibilities - assuming that the Car has been serviced
in line with the OEM Stipulations of ‘time/distance’ :
i)
That one is unknowingly steeping on the Accelerator pedal. It should be
totally left alone while cranking an Mpfi – whether from cold or
hot.
ii)
One is not allowing enough time for the ‘in-tank’ fuel-pump
to 'prime' the System, as evidenced by an audible 'click' sound in the
Cabin of the FP going off after a few secs of turning on the ignition.
iii)
That one is giving too short a Crank. The first one in the mornings has
to be relatively a little longer than the ones during rest of the day.
iv)
Faulty Coolant Temp and Air Intake Sensors/their Couplers - usually the
latter for Cars less than 3-yrs old.
v)
Worn out or larger than recommended Sparkplug Gaps.
vi) Partially clogged Fuel-Injectors – if one has not been using
a good Petrol Additive regularly like a daily Vitamin Pill - which is
a must with our regular/unleaded Petrol. And if planning to switch over
to the pre-detergent mixed fuels now available, make sure one starts with
a full tank with them. Otherwise, one runs the risk of losing one’s
Fuel Pump due to the high concentration of dislodged gums and glues finding
their way back into the Tank – especially with cars > 3-yrs old
!
3)
Bharat Stage III Pollution Norms
These came into force for the designated metros and sub-metro’s
with effect from 1st April 2005 and are obviously more stringent than
the outgoing BS-II. The main difference between the two is that BS-III
stipulates ceilings on emission of various pollutants on a ‘per
km/litre engine capacity’ basis’ also, over and above those
while idling. Besides, for the latter, the ‘warm-up’ time
has been reduced considerably.
For further details, one can surf the following URL (pp 6-7) :
http://petroleum.nic.in/ch_12.pdf
4)
SOHC/DOHC
These days, the various USP’s in this respect often confuse people.
Therefore, it’s worthwhile to know what exactly such jargon means.
As you may be aware, 'push-rod' type engines of the '50s graduated to
'Single Over Head Cam/SOHC' types on stock cars by the late '60s and later
with the advent of > 2-valves per cylinder - to 'Double Overhead Head
Cam/DOHC' ones.
All these SOHC/DOHC developments were aimed at more precise control over
the 'valve timing' vis-a-vis piston movement and in turn, better 'volumetric’
and pollution control efficiency of the engine and all its attendant benefits.
SOHC engines having 2-Valves per cylinder can have their eventual valve
actuation either direct such as in Tata Diesels or via 'rocker arms' -
as seen in earlier push-rod engines like the Amby-Nova/Premier Padmini
and in all present MUL 2-4V/Cyl engines. Direct acting SOHC/DOHC offer
better valve timing control but are not very user friendly when it comes
to 'servicing' them – besides being more expensive to produce.
To get max possible performance and fuel-efficiency out of a 4-V/Cyl engine,
where costs can take a back seat, it becomes desirable to get rid of the
valve rockers and resort to DOHC/direct valve actuation - such as in the
Hyundai Accent-1.6 DOHC doing a max 103 Bhp whereas the 1.6 lr MUL/Baleno
SOHC does only 94 bhp – both with 4-V/Cyl.
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