bmcmvox

I am seeing a lot of Z owners saying that you should, and they do, fully depress the clutch (to the floor) during each shift. I am curious to know the reason (other than if says it in the manual) they say to do this. The bite point is at like 25 percent depressed, so why would you slam it to the floor? I find that by the time I push that goliath that 50 feet swing it takes to touch carpet, shift and then release smoothly (not drop) my RPMs are at 1000 and my car bucks. At 4, 5, and 6 I can practically tap the clutch and shift in like 1 second. I know I am making it slip but only for a second.1st to 2nd I depress to just before the bite (1/3 to floor), this gives me plenty of time to gently release and still hold my RPMs. 2-3 is about the same.

So whats the deal.

winchman

The contact surfaces of the disc don't disengage all at once, and some torque will be transmitted as long as there's any contact. It won't be enough to move the car, but it will definitely put more load on the synchronizers as they try to match the speed of the input shaft to the newly-selected gear.

Judging from the number of complaints about failing synchronizers, they have enough trouble already dealing with the mass of the input shaft and clutch disc.

bmcmvox

Ok, fair enough. But if you can execute faster shifts thus minimizing contact time by depressing the clutch partially (especially in 4-6 gear) wouldn't that make it better than depressing it all the way and exposing it to all that contact time during the full and complete up swing? I mean, I will never dump the clutch, not even on 5-6 on a full depressed shift. Been the done that jerk jerk lurch so for me at least, fully depressing the pedal and then smoothly releasing it would cause more slippage at higher RPM.

Any thoughts?

sk8r776

Because its the way its supposed to be driven. More wear on the clutch if not fully depressed and you'll burn it out faster. Its not that difficult. Adjust your driving style. Every car is different.

NinerZ

When I drive my Z, with a stock clutch, I only have to depress the clutch about 1/2-2/3 to the floor and the clutch fully disengages. It really makes it a rougher ride, especially in lower gears, if I put it all the way to the floor.

terrasmak

iTrader: (8)

Sounds like the latest generation of laziness not wanting to push that clutch the extra 1.5 inches.

hellman_x

iTrader: (3)

That is because you are not fully disengaging or slipping the clutch. Premature clutch wear.

Italianjoe1

iTrader: (6)

So, the rpms fall too much while you shift?

Easy fix.

There is a pedal on the right that is used to control engine speed. If you tap it lightly while shifting (up or down) you can bring everything up to speed no matter how long you have the clutch down, and if done perfectly it would remove almost all wear from the synchros.

VqBrickYard

Can you please be more descriptive on that, because I have the same problem While shifting . rpms drop pretty quickly and I'm pressing clutch all the way in.

Jennifer 2

One of the advantages of the diaphragm style clutch spring as used in a Z’ clutch assembly, is the sharp and clean disengagement point. As the clutch pedal is pushed down, the throw-out bearing is brought to bear against the diaphragm fingers bending them over a fulcrum built into the clutch cover and applying a lifting force to the clutch pressure ring. The disengagement movement in not perfectly liner in its travel as the first bit of travel is absorbed in the spring on the throw-out side of the fulcrum. However, once the diaphragm starts to flatten out, all further movement is transmitted over the fulcrum point snapping the pressure ring open and instantly releasing the clutch disk.

My dad used to mix and match engine and transmission combinations on hot rods and needed to fabricate clutch and linkage systems. He would only give a small amount of pedal travel past the engagement point for extra adjustment, component flex etc.

As bmcmvox and Niner have stated there is no need to push the Z's pedal all the to the floorboards for every shift. There is no benefit as the transmission internals don’t know or care what you do with the clutch pedal past the point of clutch disengagement.

The high clutch pedal position is just one of those charming oddities that give the Z so much personality.

vodka

The post is addressing the idea of revving the engine between shifts to better match the speed of the car in a certain gear. Same concept applies when you downshift, you want to rev-match for a smooth gear transition.

However, with regard to this and the original post's idea, it just takes practice to get a smooth, fluid gear shift. Once you learn to shift quickly it becomes a non-issue.

winchman

You need to remember that the clutch disc floats on the splined input shaft, and it can slide back and forth between the flywheel and pressure plate (clutch cover) when the clutch is disengaged (pedal down). It's likely to be barely touching a little on one side or the other if the clutch pedal isn't all the way down. The further the pedal is down, the less likely it is that it'll touch.

J 0 K 3 R

u know a lot about transmissions jennifer2. i am not a trans expert and i just hit every clutch to the floor, its faster for me. if anyone is having issues just practice kicking in the clutch and shifting faster. ive never had a problem with the z clutch pedal. the high engagement is just a better margin for error for missing a gear imo. try an old school chevy manual trans its like a 1 foot stroke of the pedal and superslopapotomous.

bmcmvox

Ok guys. Bad habbit I had. I just became very used to doing it the way I described in the original post because it was easier for me when I was learning and couldn't shift fast enough. I just got used to it. Tried dropping it to the floor during each shift today and no difference in my shift. I can now shift fast enough for it to become a non issue for me and now I can prolong th elife of my clutch... I was even doing smooth shifts from 1-2.

Thanks guys for the input!

Jbakes727

iTrader: (3)

How long have you been driving stick?

Z33Garage

iTrader: (3)

I have noticed that when I shift from 2-3 or 4-5 if the clutch isnt all the way down it tends to grind slightly before it engages. This only happens sometimes. All other gears are fine. I always depress the clutch all the way, regardless of vehicle :/

Spike100

You can shift your manual Z without depressing the clutch by matching engine speed to the drivetrain speed. Of course, doing this is foolish for the amount of wear and tear you put on the drivetrain

The best way to shift your MT is a fully depressing your clutch pedal. This way you know you minimize wear.

--Spike

TuckerE36

iTrader: (3)

Nothing like floating through gears! hahaha

Golden_Armz

iTrader: (3)

if you dont have to fully depress the clutch, then whats that little button for?

Jennifer 2

Bmcmvox, Go7roo7, et al, there is a little skill and experience involved here. You must learn where the complete disengagement point is and be able to push the clutch pedal just a bit past that point on a repeatable basis. (Obviously if you don’t push it far enough the gears will protest) If you feel safer bottoming out the pedal with every shift though, go for it.

Winchman you’re reaching pretty hard here to find some possible theory to prove a point. I doubt you’ve actually seen any measurements on this. In practice, the pressure plate can only travel a set amount to where diaphragm spring flattens out and approaches the over-centering region. At this point the spring/fulcrum geometry changes and that extra push on the pedal doesn’t do much. On a hot day, with a little hydraulic fluid expansion, some Zs have had the pedal stick in the down position, there a few causes for this, but the fact that the diaphragm spring comes close to an over-center situation contributes to this malady.

I’m not an auto technician or engineer, or even a fan of working on cars. I was my dad’s conscripted helper though, when he adapted all new transmission internals and clutch operating linkage (including mapping out the clutch and pedal link geometry for my first sports car. Vintage MGB’s didn’t feature any synchromesh for first gear. He machined and installed one, as well as modernizing the others.

The last inches of pedal travel on a Z don’t actually provide much extra plate movement. Drag racers have actually measured the travel and have installed pedal stops to provide faster and more precise gear shifting without damaging anything. RJM performance, a vender here, makes and sells a adjustable pedal bracket that lets you dial in this and more. It greatly improving the clutch action, and by extension also the shifting action, I think it has received great reviews.