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Wondering if anybody has any advise or idea's for my problem. I took my recently aquired '82 280ZX to the wednesday night drags here in Sonoma,CA a couple months back. This was the first time I've drag raced, although had an idea since I grew up with my dad driving top fuel in my younger years.
Anyway, my problem was with leaving the line. First of all, my car is bone stock with 180,000 miles, and is my daily driver. I didn't know how I should launch this thing, but when I got to the light, my adrenaline started pumping and I took the rpm's up to about 4000 and slid my foot of the side of the cluth pedal when the light turned green. It felt like it really wanted to go, but the clutch spun like ****. I had two more passes, and although being a little easier on it after that, by the 3rd run, the clutch was spinning in every gear, even when I shifted into 4th! Needless to say, my time went from 16.5 to 17.8, and my car smelled like clutch dust for a couple of days. I wondered why this happened since the clutch was changed by a tech in the dealership that I work for about 5o miles before I bought it.
The clutch used was an aftermarket Borg/Warner, but it seems to me that the rear wheels should have spun, and not the clutch. Would this have happened anyway because of the rpm that I left at, or do I have something else wrong? And yes, I do have freeplay in the pedal. Anybody who has taken the time to read my exhaustive story and has any helpful hints, please let me know! Thanks!
 

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is your car a coupe or 2+2? the coupes had a clutch with a less clamping force than a 2+2. in my experience, the clutch in the coupe is not adequate for racing. i've had my clutch slip with the parking brake on. the borg warner aftermarket clutch is probably just a stock replacement part, therefore it is also inadequate. a 4k launch would definitely cause the clutch to slip. look into getting a 2+2 flywheel and clutch or go with a heavy duty aftermarket one like a centerforce.
 

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> is your car a coupe or 2+2? the coupes had a
> clutch with a less clamping force than a
> 2+2. in my experience, the clutch in the
> coupe is not adequate for racing. i've had
> my clutch slip with the parking brake on.
> the borg warner aftermarket clutch is
> probably just a stock replacement part,
> therefore it is also inadequate. a 4k launch
> would definitely cause the clutch to slip.
> look into getting a 2+2 flywheel and clutch
> or go with a heavy duty aftermarket one like
> a centerforce.
If you do convert to a 2+2 set up on a coupe, make sure that you also get the correct throwout bearing sleeve, which is slightly shorter than the coupe t/o sleeve. If you don't, you may end up doing the clutch twice. We have got customers cars in that slipped with brand new clutch done elsewhere, and had to r and r their trans, and put the correct parts in several times. Joe
 

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> Wondering if anybody has any advise or
> idea's for my problem. I took my recently
> aquired '82 280ZX to the wednesday night
> drags here in Sonoma,CA a couple months
> back. This was the first time I've drag
> raced, although had an idea since I grew up
> with my dad driving top fuel in my younger
> years.
> Anyway, my problem was with leaving the
> line. First of all, my car is bone stock
> with 180,000 miles, and is my daily driver.
> I didn't know how I should launch this
> thing, but when I got to the light, my
> adrenaline started pumping and I took the
> rpm's up to about 4000 and slid my foot of
> the side of the cluth pedal when the light
> turned green. It felt like it really wanted
> to go, but the clutch spun like ****. I had
> two more passes, and although being a little
> easier on it after that, by the 3rd run, the
> clutch was spinning in every gear, even when
> I shifted into 4th! Needless to say, my time
> went from 16.5 to 17.8, and my car smelled
> like clutch dust for a couple of days. I
> wondered why this happened since the clutch
> was changed by a tech in the dealership that
> I work for about 5o miles before I bought
> it.
> The clutch used was an aftermarket
> Borg/Warner, but it seems to me that the
> rear wheels should have spun, and not the
> clutch. Would this have happened anyway
> because of the rpm that I left at, or do I
> have something else wrong? And yes, I do
> have freeplay in the pedal. Anybody who has
> taken the time to read my exhaustive story
> and has any helpful hints, please let me
> know! Thanks!

Hey Bud- I have a 82 ZX N/A also 180 thou as well. I never drag race but I do autoX. The launch that I use brings the car out fast, and really doesn't hurt the clutch either. I bring it up to about 3500, but do not side step, I just launch the car firm. Bring the clutch out until it starts to pull and squeeze the throttle to the floor. It will take some time to get the light you are looking for, but this should get the car out of the hole w/o bogging the engine or burning the clutch/rear tire.

Happy racing!! -Ken
 

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Drivers point of view,

> Wondering if anybody has any advise or
> idea's for my problem. I took my recently
> aquired '82 280ZX to the wednesday night
> drags here in Sonoma,CA a couple months
> back. This was the first time I've drag
> raced, although had an idea since I grew up
> with my dad driving top fuel in my younger
> years.
> Anyway, my problem was with leaving the
> line. First of all, my car is bone stock
> with 180,000 miles, and is my daily driver.
> I didn't know how I should launch this
> thing, but when I got to the light, my
> adrenaline started pumping and I took the
> rpm's up to about 4000 and slid my foot of
> the side of the cluth pedal when the light
> turned green. It felt like it really wanted
> to go, but the clutch spun like ****. I had
> two more passes, and although being a little
> easier on it after that, by the 3rd run, the
> clutch was spinning in every gear, even when
> I shifted into 4th! Needless to say, my time
> went from 16.5 to 17.8, and my car smelled
> like clutch dust for a couple of days. I
> wondered why this happened since the clutch
> was changed by a tech in the dealership that
> I work for about 5o miles before I bought
> it.
> The clutch used was an aftermarket
> Borg/Warner, but it seems to me that the
> rear wheels should have spun, and not the
> clutch. Would this have happened anyway
> because of the rpm that I left at, or do I
> have something else wrong? And yes, I do
> have freeplay in the pedal. Anybody who has
> taken the time to read my exhaustive story
> and has any helpful hints, please let me
> know! Thanks!

I am not a mechanic, but I have been driving a variety of diffrent Z's for about 3 years, and I have been racing for about 5, so all of my answers and posts come from personal experience.

Ok, lets start at the begining. First off, a Z with 180,000 miles, doesn't want to be drag raced if you want to keep it as an everyday driver much longer. Hopefully you have rebuilt engine that you are romping on.

OK, about the clutch. You need to take it real easy on a new clutch. Most manufacters say cruise for the first 500 miles. Since you didn't give the clutch a chance to break in, you may have just ruined it permantly. Sorry to be the bearer of this crappy news, but hey, someone has to tell ya.

What you did, is glaze the surface of the clutch, thus disallowing the gripping power of the disk. It's nice and slick now, and will just spin and spin and spin, until you have about a half inch worth of dust in the bottom of your tranny.

Is the clutch slipping now, as you drive around town? Does it slip if you jump on the gas above 3000rpm.

What you need to do from here is just sputter around town on the clutch, to see if you can regain some of the ability of the disc. Give it about 500 miles, and try it again. Keep your shifting below 4000rpm for a while, and don't try to put to much undue pressure on it. Don't, lay on the gas, before you know that the clutch is finished, to avoid any further slipping.

Hopefully everything is salvagable, and you havn't ruined it. Would be a bummer to have to take out a new clutch, and replace it with another one.

BTW, I had a Berg-W in my Z for a while. The Z had about 210 horsepower at the time, and the clutch was great. I was very pleased with the quality of the system, and almost wish I had bought another one. Unfortunatly, I let someone talk me into buying a Centerforce I, and I am not pleased. I now have 250 horsepower, and the Centerforce I can't stand up to the launches or speed shifting. The Berg-W stood up to 4,800 launches with M/T slicks, and then took me down the strip in 14 seconds, with 3 speed shifts along the way. The Centerforce only lasted about a month, even while just driving around town.

Let me know how this turns out. Good luck.

Chris Behney
Redline Autosports
 

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Re: Mechanics point of view

the clutch problem here has nothing to do with breaking in the clutch properly. clutches don't require nearly the time claimed by manufacturers to break in. it's just their insurance policy. if he had 50 or 100 miles on the clutch it was fine. clutch glazing is caused by excess heat, just like brake glaze. excess heat comes from excess slippage. the clutched worked great before he left the line, it just did not have the clamping force to hold a 4k clutch pedal sidestep. the same thing has happened in my coupe and the clutch still works great, there's nothing wrong with it, it's just a weak link.
 

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Re: Mechanics point of view

> the clutch problem here has nothing to do
> with breaking in the clutch properly.
> clutches don't require nearly the time
> claimed by manufacturers to break in. it's
> just their insurance policy. if he had 50 or
> 100 miles on the clutch it was fine. clutch
> glazing is caused by excess heat, just like
> brake glaze. excess heat comes from excess
> slippage. the clutched worked great before
> he left the line, it just did not have the
> clamping force to hold a 4k clutch pedal
> sidestep. the same thing has happened in my
> coupe and the clutch still works great,
> there's nothing wrong with it, it's just a
> weak link.

If he didn't glaze the clutch, how do you explain the clutch not even holding in 4th. I dought seriously that any Z with 180,000k miles has enough power to slip any good clutch.(Especially in 4th gear.) It has always been my experience to break the clutch in.

Maybe I misread, and thought it was a new clutch, but either way, it was glazed, and would not grip. No other way about it. Not tring to be rude, but if the clutch is glazed, it won't hold. Nothing to do with the plate,(pressure) when the disk is glazed. You can have an extremmly strong plate, but if the disk won't grip, then you're out of commission. Whether the clutch is old or new.

If I'm wrong, let me know.

Chris Behney
Redline Autosports
 

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Re: Mechanics point of view

i'm not saying the clutch isn't glazed, i'm just saying it wasn't glazed before he left the line. the initial slippage was caused by lack of clamping force. if he kept on letting the clutch slip then yes it would eventually glaze. but the glazing is the effect and not the cause in this situation. the glazing can be fixed by the way, by burning in the clutch, as long as you don't overdo it. it's the same as burning brake glaze off your pads.
 

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Re: Mechanics point of view

> If he didn't glaze the clutch, how do you
> explain the clutch not even holding in 4th.
> I dought seriously that any Z with 180,000k
> miles has enough power to slip any good
> clutch.(Especially in 4th gear.) It has
> always been my experience to break the
> clutch in.

> Maybe I misread, and thought it was a new
> clutch, but either way, it was glazed, and
> would not grip. No other way about it. Not
> tring to be rude, but if the clutch is
> glazed, it won't hold. Nothing to do with
> the plate,(pressure) when the disk is
> glazed. You can have an extremmly strong
> plate, but if the disk won't grip, then
> you're out of commission. Whether the clutch
> is old or new.

> If I'm wrong, let me know.

> Chris Behney
> Redline Autosports

I had a car I autocrossed, that everytime after hard launches the clutch would slip bad in all gears. Once it cooled down it gripped like it did before I raced. I got many, many more miles out of it, and it was an old clutch that was deffinitely broken in.
 

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Re: How do I burn off the glaze??

> i'm not saying the clutch isn't glazed, i'm
> just saying it wasn't glazed before he left
> the line. the initial slippage was caused by
> lack of clamping force. if he kept on
> letting the clutch slip then yes it would
> eventually glaze. but the glazing is the
> effect and not the cause in this situation.
> the glazing can be fixed by the way, by
> burning in the clutch, as long as you don't
> overdo it. it's the same as burning brake
> glaze off your pads.

How do you burn the glaze off the brakes? I think mine are glazed.
 

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Re: How do I burn off the glaze??

to burn the glaze off the brakes, just drive around for awhile at a moderate speed, say 30-40 mph. lightly apply the brakes and let them drag against the rotors. if the glaze is bad the brakes squeak or even make a grinding sound. don't let the brakes get overheated. you're actually just trying to sand the glaze off, not burn it off, that's just what they call it. just keep doing this until the noises go away. if this doesn't work, take the pads out and sand them with 80 grit. if the problem goes away but keeps coming back you may need new brake pads. rotors can also become glazed. you can sand them with 80 grit also or have them turned. a glazed rotor usually turns black or blue and is shiny.

-casper
 

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Re: How do I burn off the glaze??

> to burn the glaze off the brakes, just drive
> around for awhile at a moderate speed, say
> 30-40 mph. lightly apply the brakes and let
> them drag against the rotors. if the glaze
> is bad the brakes squeak or even make a
> grinding sound. don't let the brakes get
> overheated. you're actually just trying to
> sand the glaze off, not burn it off, that's
> just what they call it. just keep doing this
> until the noises go away. if this doesn't
> work, take the pads out and sand them with
> 80 grit. if the problem goes away but keeps
> coming back you may need new brake pads.
> rotors can also become glazed. you can sand
> them with 80 grit also or have them turned.
> a glazed rotor usually turns black or blue
> and is shiny.

> -casper

Thanks Casper for the response. My brqkes only squeek when they are warmed up and the squeeking stops when I apply the brakes. I am going to sand the rotors, but replace the pads. I bought them at Checker and they suck. They seemed better before I replaced them. The problem is they fade quickly. During normal stop and go driving they are good, but when using them on some winding road at faster speeds, stopping is kind of scary.

I was thinking of getting the ones from Victoria Brittish. Would you recomend them?
 

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Re: How do I burn off the glaze??

those pads appear to be good quality, but they are overpriced. i'm looking at the semi-metallic pads, which is what you want, they cost $40 for the front and $35 for the rear. that's expensive. also if your shims are missing, buy new ones. these prevent brake squeak as well. the pads should come with that blue goop that goes on the back of the pads. pick up some anti-sieze or copper coat if you don't have some. bg (bearing-gear) makes a product that you apply to the pad itself. it soaks into the pad and prevents squeak without lowering braking ability or pad life. a shop i worked at used this stuff on every customer car, never had a complaint.

-casper
 

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Re: How do I burn off the glaze??

> to burn the glaze off the brakes, just drive
> around for awhile at a moderate speed, say
> 30-40 mph. lightly apply the brakes and let
> them drag against the rotors. if the glaze
> is bad the brakes squeak or even make a
> grinding sound. don't let the brakes get
> overheated. you're actually just trying to
> sand the glaze off, not burn it off, that's
> just what they call it. just keep doing this
> until the noises go away. if this doesn't
> work, take the pads out and sand them with
> 80 grit. if the problem goes away but keeps
> coming back you may need new brake pads.
> rotors can also become glazed. you can sand
> them with 80 grit also or have them turned.
> a glazed rotor usually turns black or blue
> and is shiny.

> -casper
Casper, I remember Datsun telling me many years ago to do this to get rid of the brake squeal.
The only difference was they said to go backwards, and of course not that fast. It used to work for a week or two, and then I'd have to do it again. Now, the parking lots are too crowded
to go backwards! Joe
 

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Re: How do I burn off the glaze??

> Casper, I remember Datsun telling me many
> years ago to do this to get rid of the brake
> squeal.
> The only difference was they said to go
> backwards, and of course not that fast. It
> used to work for a week or two, and then I'd
> have to do it again. Now, the parking lots
> are too crowded
> to go backwards! Joe

personally i think taking out the pads and sanding them works better. that and taking a roloc pad to the rotors. burning in the pads is usually a temporary fix. but then again it's probably the way i drive. my last z i turned the rotors a nasty purple-black color. they never squeaked that much though. it's funny that datsun told you to do that, i've never heard that from a car company. i can see where driving backwards would work better. that's a lot of driving in reverse.
 

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Re: How to get rid of brake squeal

> personally i think taking out the pads and
> sanding them works better. that and taking a
> roloc pad to the rotors. burning in the pads
> is usually a temporary fix. but then again
> it's probably the way i drive. my last z i
> turned the rotors a nasty purple-black
> color. they never squeaked that much though.
> it's funny that datsun told you to do that,
> i've never heard that from a car company. i
> can see where driving backwards would work
> better. that's a lot of driving in reverse.

I have a 78 2+2. When I did my first brake job many years ago it started to squeal BAD. I lived with it, with embarassment, for several months. I put in new calipers and changed the pads again. Still no improvement.

Finally, I decided that I'd let the professionals do it, turn the rotors, their high quality pads, etc. One week later it was squealing BAD. So I took it back to them (a brake specialty shop, good reputation). They tried again, and sold me some special pads. After $130, It still squealed BAD.

So I gave up for a while. Then I talked to the boys at Motorsport in CA. They told me to install their disk brake hardware kit with some new pads and the problem would go away. $15 for the kit.

It worked. Put in new shims, new pins, and liberal brake grease. I haven't had a problem since. I didn't turn the rotors either.

So don't live with the awful squeal. In my case it was rusty old hardware that allowed the vibration while braking.

Matt
 
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