Clutch Bypass mod

[davey_83]

Has anyone else done this and in reality is there any adverse effects, providing the car is started when in neutral? I've never had a car that wouldnt start without the clutch being depressed and don't see the benefits?

 

I've read operating a dry clutch release bearing every morning, causes additional internal wear compared to operating once the clutch is already spun up.

 

[ZMANALEX]

I always advise customers and forum members to leave the clutch pedal start, to work the way it is meant to from the factory.

 

However the one exception to this is when the clutch start switch fails and the bypass is required as a temporary measure to get the car started.

[davey_83]

Why do you advise this? 

[ZMANALEX]

1 hour ago, davey_83 said:

Why do you advise this? 

The clue is in the switch description which is "Clutch Safety Switch"

However, as you are aware, providing the car is in Neutral then there should be no adverse effects.

But, many cars have multiple drivers so I would consider a fully working clutch safety switch imperative and that is the advise I give to others when asked.

 

[350Butcher]

I’ll be carrying out this mod for my new engine as I hate the idea of loading dry thrust bearings (that have no forced oil feed and are just splash fed) every time the car is started. 
 

My friends at the machine shop have noticed all modern engines that are stripped down are suffering much increased wear to thrust bearings and in many cases to the point that they are out of tolerance as a direct result of being starting with clutch pedal depressed. 
 

With uprated heavy clutch pressure plates the effects with be made even worse due to the increased pedal pressure required.

Edited October 18, 2019 by 350Butcher

[stoofer]

Starting the car when it's on a lift is a PITA. I'd consider this mod (with a switch to disable it) for that alone.  Unless thrust bearings are failing before clutches need replacing (are they? I haven't been here very long), I don't see a need to do it to save the bearing.

[ZMANALEX]

There is no extra load or premature wear on the clutch release bearing when having to press the clutch to engage the starter.

 

There is also no forced or splash feed lubrication as the bearing is self lubricating.

 

The OEM Koyo clutch release bearing will out last most clutch kits.

 

The bearing only turns once the pedal is depressed, so in theory the bearing will turn slower with the switch fully working as opposed to turning faster with the switch by passed.

 

So the choice of this mod is fully with the operator as it will not be detrimental to any other perceived mechanical issues.

 

It is purely a safety feature which most modern manufacturers deem advantages for the safe operation of vehicle start up.

 

I agree that start up on a ramp is a PITA, however safety again comes into the equation as it will not be the first time that I have seen a car shoot forward or even off a flat bed ramp due the technician starting the car whilst standing outside the car and not noticing that the car was in gear.

 

 

[350Butcher]

Agree with all of the above with regards to the clutch release bearing but my post was regarding the crank thrust bearing which is loaded when dry (by depressing the clutch) and then the engine is cranked to start so I will be carrying out this mod to protect my brand new engine as it’s just unnecessary and has no plus that I can see only the negative that I mention here. 

[ZMANALEX]

15 minutes ago, 350Butcher said:

Agree with all of the above with regards to the clutch release bearing but my post was regarding the crank thrust bearing which is loaded when dry (by depressing the clutch) and then the engine is cranked to start so I will be carrying out this mod to protect my brand new engine as it’s just unnecessary and has no plus that I can see only the negative that I mention here. 

Manual transmission cars with the older style three-finger Long or Borg & Beck clutch pressure plate designs, apply increasing pressure as the clutch pedal is pushed to the floor. This produces maximum forward thrust on the crankshaft while attempting to start the engine.

 

Diaphragm pressure plates go “over centre” at full release which applies only limited forward thrust.

 

So the technique for a car equipped with a Long or Borg & Beck clutch is merely to start the engine in neutral.

This eliminates potentially excessive wear on the thrust bearing.

 

However, the modern diaphragm type clutches which are in the 350Z do not have this issue so it is quite safe to start the engine with the clutch pedal depressed without worrying about wear on the crank half moon bearings.

 

However, I accept that if you have no safety concerns, then  I see no reason why not to carry out this mod, I get your point, but I doubt if you would experience less wear on the thrust washers with the switch being fully active than without, but whatever you are comfortable with.

 

Good luck with your build. 

[davey_83]

It's been years since I've used cruise control, does the system deactivate when the clutch is pressed or brake pedal or both? 

[350Butcher]

16 hours ago, ZMANALEX said:

However, I accept that if you have no safety concerns, then  I see no reason why not to carry out this mod, I get your point, but I doubt if you would experience less wear on the thrust washers with the switch being fully active than without, but whatever you are comfortable with.

 

Good luck with your build. 

Cheers Alex. 
 

15 hours ago, davey_83 said:

It's been years since I've used cruise control, does the system deactivate when the clutch is pressed or brake pedal or both? 

Cruise is deactivated by pressing either the clutch or the brake pedal. 

[davey_83]

Ive ran mine to switch, so its not permanently active. From now until the spring I clear my exterior windows, headlamps with cold water and drop the bollard - so its nice to just lean in start the car beforehand.