Old wives tales or not ???
Old wives tales or not ???
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Discussion

razorman

Original Poster:

440 posts

259 months

Saturday 3rd September 2005
quotequote all
As I have previously confessed I know very little about the mechanics of a car. So I have a couple of questions that hopefully some technically minded people can shed some light on.

1) I always dip the clutch when I start the car. I vaguely remember reading somewhere that this is not a good thing to do. Which is correct and why?

2) Just before turning the engine off some people blip the throttle does this do any good or harm?
(apart from being able to hear the engine sound for just one last time)

Number 7

4,113 posts

291 months

Saturday 3rd September 2005
quotequote all
Starting with the clutch depressed is a good idea, I do it all the time. It removes the drag of the gearbox, giving the starter an easier time, and also means that if the car is still in gear when started, you don't ram something.
I don't think blipping actually does any good, but I'm not sure whether its harmful with modern engines. Theoretically, engines prefer to work under load.

7.

Cider Andy

1,889 posts

254 months

Saturday 3rd September 2005
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7 is exactly right about always starting the car with the clutch pedal down.

It was always good advice to never blip the throttle just before switching off. On cars with carburettors it leaves unburnt fuel in the cylinders which, over time, will accelerate wear in them. However, on modern day cars with electronic fuel injectors this shouldn't be a problem.

mongoose

4,360 posts

284 months

Saturday 3rd September 2005
quotequote all
Just to give an alternative view to point number 1.I was strongly advised,upon the renewal of my bottom end bearings,not to press the clutch pedal when starting.With slivers of bearing in hand,my mechanic explained how much pressure your putting on the faces of the thrust bearing by holding the clutch down.Then your spinning the crank at a fair old rate,and all this is happening whilst all the oil is still in your sump,ie bearings are near dry.Never held the clutch down whilst starting scince!

Cider Andy

1,889 posts

254 months

Saturday 3rd September 2005
quotequote all
If the oil in the sump is anwhere near the clutch thrust bearing, you've a lot more to worry about than where your left foot is!

GreenV8S

31,018 posts

313 months

Saturday 3rd September 2005
quotequote all
I think Mike is talking about the thrust washer at the front of the crankshaft, which is what ultimately stops you pushng the crankshaft out the front of the engine when you press the clutch pedal down.

Even if the engine hasn't been run for a few months the thrust washer should still have an oil film, it shouldn't suffer any significant damage from starting the engine with the clutch down.

tahiti450

712 posts

266 months

Sunday 4th September 2005
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GreenV8S said:
I think Mike is talking about the thrust washer at the front of the crankshaft, which is what ultimately stops you pushng the crankshaft out the front of the engine when you press the clutch pedal down.

Even if the engine hasn't been run for a few months the thrust washer should still have an oil film, it shouldn't suffer any significant damage from starting the engine with the clutch down.


Absolutely, took the words out of my mouth.

(but.., just for the pedants.., on the RV8 it's the centre main bearing (top) that has the thrust bearings integral with the shell)

GreenV8S

31,018 posts

313 months

Sunday 4th September 2005
quotequote all
tahiti450 said:
on the RV8 it's the centre main bearing (top) that has the thrust bearings integral with the shell
Got a picture of that? I'm having trouble visualizing it.

Cider Andy

1,889 posts

254 months

Sunday 4th September 2005
quotequote all
My apologies, Mike, I misunderstood you, my fault.

tahiti450

712 posts

266 months

Sunday 4th September 2005
quotequote all
GreenV8S said:

tahiti450 said:
on the RV8 it's the centre main bearing (top) that has the thrust bearings integral with the shell

Got a picture of that? I'm having trouble visualizing it.


The centre main bearing shell has the crankshaft thrust bearings formed as flanges on the shell. Correcting myself tho' it is both halves of the shell, not just the upper. Haven't got a pic to send but any RV8 manual shows this.

razorman

Original Poster:

440 posts

259 months

Sunday 4th September 2005
quotequote all
OK so if I understood the comments correctly.

1)The general concensus is that it doesn't do any harm if I depress the clutch whilst starting and it obviously acts as an extra precaution in case the car has beeen left it in gear.

2) Blipping the throtle before turning the ignition off on the Chim is neither good nor bad (apart from one last chance to hear the sound)

boosted ls1

21,200 posts

289 months

Sunday 4th September 2005
quotequote all
Bearings should have lube on them even from a fresh build so I always dip the clutch when I start a car. Makes it so much less work for the battery and starter. Leaving more power for spark productionand efi events.

Boosted.

Wacky Racer

41,345 posts

276 months

Sunday 4th September 2005
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Well I have always pressed the clutch pedal in, when starting, and never worn a clutch out yet, in 35 years driving.......

However, I did once start a three cylinder Yamaha 750 in a pub carpark, which was in first gear, and forgot to pull the clutch lever in, the bike lurched forward, and knocked a table over, spilling an old couples drinks all over the floor..........

Hence why most large capacity modern bikes won't start UNLESS you pull the clutch lever in......

B17NNS

18,506 posts

276 months

Monday 5th September 2005
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My girlfriend has a new shape 320d (with a starter button) and it won't let you start it without engaging the clutch.

Cider Andy

1,889 posts

254 months

Monday 5th September 2005
quotequote all
Wacky Racer said:
However, I did once start a three cylinder Yamaha 750 in a pub carpark, which was in first gear, and forgot to pull the clutch lever in, the bike lurched forward, and knocked a table over, spilling an old couples drinks all over the floor..........


A classic!

Of course I wouldn't have laughed if it'd been my cider.

ginganinga

390 posts

306 months

Monday 7th November 2005
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Chrylser Neons won't start unless the clutch is depressed, I'm guessing it's because Americans are far more used to Autos though...
I remember when a mate took my old S3c home, he left it in gear and as I wanted to warm it up I just leant in to start it up, it shot off across the drive. Luckily my reaction was to jump in sideways, knock it out of gear and grab the handbrake, luckily just stopping it centimetres from the fence!

Paul (93 Chim)

144 posts

262 months

Monday 7th November 2005
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[quote=ginganinga]Chrylser Neons won't start unless the clutch is depressed, I'm guessing it's because Americans are far more used to Autos though...

Americans must take along time looking for a clutch pedal on an auto!