# Clutch in start - bad for car/engine?



## r34skyline (Oct 20, 2004)

Hi,

just wanted to get some peoples opinions on any negative side effects to clutch in starting of a r34 GTR...

workshop the car is taken too said to change it as it was bad for something a rather, which they think had cost an engine of at least one person they know, or a customer etc. 

I don't know if the clutch in start was something that Nissan had from factory with r34 gtrs, all i know is that it's been changed from pull to push, or the other way around  - so i'm not sure if the clutch in start was changed then as well. 

If it is a factory procedure, i would find it hard to believe it's detrimental to the car? it's a built 26, but i wouldn't think that would make a difference?

anyways, just thought i'd get some opinions on whether i should change it next service


cheers


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## markpriorgts-t (May 23, 2004)

didnt know you had to do that on a 34

anyway on a std clutch or single plate should be OK, however twin, triple & quads can exert enough pressure to deform the crank slightly and rub the bearings


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## MIKEGTR (Jul 8, 2005)

It comes from years ago when starter motors weren't as strong as they are now, you are just reducing the rotating mass


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## freakazoid3 (Jan 19, 2008)

I personally never touch the clutchpedal while starting as it pust extra load on the crank's thrust bearings for no reason...So clutch untouched while starting I would say :thumbsup:


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## blue34 (Jul 28, 2005)

my 350zgt won't start at all unless the clutch is pressed in (some kind of safety feature) so obviously Nissan don't think this will do any harm, at least not during the normal life of an engine. Maybe if you were using a high spring pressure drag clutch it might not be a good idea but generally I doubt this would bother a thrust bearing too much even while the oil pressure is building, considering how many hundreds of times a day the clutch pedal is depressed during driving in a traffic jam.


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## blue34 (Jul 28, 2005)

markpriorgts-t said:


> didnt know you had to do that on a 34


You don't....


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## bluesky (Mar 12, 2006)

I have to put clutch in to start my 34.


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## R.I.P.S NZ (May 7, 2004)

I'd definatly bypass it especially if you have an aftermarket clutch, its not good for the thrust bearings and definatly can lead to premature engine failier (also check that your clutch has had the free play set correctly.)

Just join the wires at the plug so the ecu thinks you have the clutch in all the time.


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## blue34 (Jul 28, 2005)

bluesky said:


> I have to put clutch in to start my 34.


Never seen that before? Is it a UK model specific thing or has mine been disconnected before I bought it? I can't think of any reason to push the clutch in if you don't have to, unless of course you don't check it's in neutral first and agree any wear is best avoided if you can.

I once accidentally started an Alfa 156 in gear and the jerk forward tripped the fuel cut off so it wouldn't start. That took a bit of head scratching but eventually found it and reset it, it was under the passenger seat


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## mattysupra (Oct 31, 2008)

R.I.P.S NZ said:


> I'd definatly bypass it especially if you have an aftermarket clutch, its not good for the thrust bearings and definatly can lead to premature engine failier (also check that your clutch has had the free play set correctly.)
> 
> Just join the wires at the plug so the ecu thinks you have the clutch in all the time.



Robby, 

How do you set free play? What is free play? 


Thanks in advance!


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## R.I.P.S NZ (May 7, 2004)

mattysupra said:


> How do you set free play? What is free play?


And people wonder why they destroy engines/bearings.:nervous::nervous:

Not something I can explain on here sorry, your tuner should set it for you.


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## r34skyline (Oct 20, 2004)

it is a Nur, so maybe the later models had clutch in start?

Either way, if people like Rob think i should change, that's good enough for me  The clutch is a twin-plate carbon ATS job, fantastic clutch if people are thinking what to get, very light and is handling some decent power

i'll make sure to get it changed at the workshop here, thanks guys!!!


EDIT: i'll also get them to check the free-play too


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## bluesky (Mar 12, 2006)

Never seen that before? Is it a UK model specific thing or has mine been disconnected before I bought it? I can't think of any reason to push the clutch in if you don't have to, unless of course you don't check it's in neutral first and agree any wear is best avoided 

Hi blue34, mine is an import 2001 model.


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## freakazoid3 (Jan 19, 2008)

blue34 said:


> my 350zgt won't start at all unless the clutch is pressed in (some kind of safety feature) so obviously Nissan don't think this will do any harm, at least not during the normal life of an engine. Maybe if you were using a high spring pressure drag clutch it might not be a good idea but generally I doubt this would bother a thrust bearing too much even while the oil pressure is building, considering how many hundreds of times a day the clutch pedal is depressed during driving in a traffic jam.


If you press the clutch with the engine running there is no problem as there is oilpressure in the bearings, but on startup there isn't and you create much more wear much quicker then under normal load condition during engine operation...So bypass the switch at the pedal and be done with it :thumbsup:

I always feel the gearstick and make sure she's in neutral before starting a car anyway so no worries there either...


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## blue34 (Jul 28, 2005)

freakazoid3 said:


> If you press the clutch with the engine running there is no problem as there is oilpressure in the bearings, but on startup there isn't and you create much more wear much quicker then under normal load condition during engine operation...So bypass the switch at the pedal and be done with it :thumbsup:
> 
> I always feel the gearstick and make sure she's in neutral before starting a car anyway so no worries there either...


I don't disagree in theory and agree it's not good practice, but like i say I don't think it would do any harm over the life of a normal engine with a standard clutch, there would be a lubricating film on the bearing even at start up unless it's been left for months. For example there is a 2006 350z GT on piston heads with over 100,000 miles on the clock right now, that car would have had to have had the clutch in for every start so go figure.

As for free play Matty. The clutch thrust bearing should have a small amount of clearance off the clutch cover when the pedal is up simples... 

If the cylinder operating rod is too long, if the cylinder piston isn't fully returning, if the clutch release bearing carrier isn't suitable for the clutch etc etc.. All these things can result in no free play ie there could be constant pressure being applied to the clutch cover and therefore the crank thrust bearing. Obviously this is a lot worse for bearing wear than starting with clutch in.


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## r34skyline (Oct 20, 2004)

well it seems like there's SOME potential for damage with clutch-in but none for disabling it, so i'll get it sorted asap

I'm inclined to think it's fine as this car was built at Midori, so i'm sure they know the score, but there's no harm in disabling it, so it seems the best course of action


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