Car Shudder

[MinusG40]

Hi ,

Since a few weeks n the car started shuttering quite alot upon takeoff from a dead stand still. Does this in forward and quite less in reverse.

The engine mount have been change by the previous owner.

What could cause this issue ? Can you tell me (or show me with a pic) where are located the engine mounts (i just want to check)

Cheers

Nicolas

[superdavelotus]

After checking your engine mounts which I don't think it will be, you need to look at your clutch.

Engine mounts failing will also normally have other tell tail signs under heavy accelleration not just from take off.

Dave Walters

[MinusG40]

Hi Dave,

thank for your answer

Ok i was thinking the same. That means something is going badly with the clutch, could it be link to hyrdaulic command ?

Because if it was the clutch then i will have some spinning like a unlock converter as far as i know.

[superdavelotus]

More likely to be warped or heat spots on clutch plates or weak splines. I would live with it if you can, if you can't or if it's really bad then get it checked out by a specialist.

It's not going to be hydraulics IMO

Dave Walters

[MinusG40]

Erf one of the most costy option Thank for all yours answers Dave

Edited January 19, 2009 by USAndretti42
Removed quote of immediately preceding post

[redshift]

Clutch judder is not uncommon especially if you are too gentle or try to feed the clutch in slowly. The twin plate clutch is not damped and causes juddering in this case.

Does the shuddering stop if you release the clutch quicker?

[snuffy]

Yep, try more revs. When I first had mine the takeoff was terrible until I put a few more revs in.

Edited January 19, 2009 by USAndretti42
Removed quote of immediately preceding post

[MinusG40]

Yes i push gently the clutch pedal i will give a try with more RPM and quickly release the clutch pedal.

Cheers

Edited January 19, 2009 by USAndretti42
Please don't keep quoting what was just said

[toyroom]

Oh hell, or should I say merde ? I could probably write you a biblioteque full of books on this subject...just ask Dave, he knows all about it.

It is a very long and sometimes funny but occasionally infuriating story recorded somewhere else on this forum, but...

My car has a special gearbox with a 1 piece input shaft and taller closer ratios, a taller final drive and a limited slip differential. This means that once it is doing about 30mph it performs much better through the gears but the downside is that you are moving off in the equivalent of a gear slightly higher than the standard second gear. I have had four clutches since the 'box was fitted. The first was wrecked by a main dealer who fitted the gearbox. The second juddered like you describe and I replaced it and the third was damaged by overheating. The fourth was fitted by the factory along with all new bits and a new flywheel. And it judders just the same.

I tried driving Dave's car and doing a hill start in second, the judder was exactly the same only less pronounced.

The factory got their transmission guy and the AP guy (clutch maker) involved and they decided that the judder was normal and simply more obvious with this taller gearbox.

Right:

1. The judder is much less in the Summer.

2. It is worse once the clutch is warm (after a spell in slow traffic for example).

3. It happens at exactly 1400 revs

4. It It happens right at the end of the travel and hence is probably the second plate final take up.

5. The factory described it as "acceptable"

I therefore suggest that this is a coefficient of friction problem with a bit of resonance thrown in. It seems better when it is dry (Summer) and yet worse when it is hot (traffic jam).

It is easy to overcome by keeping the revs above 1400 but this means slipping the clutch a bit and may increase wear.

I can say this: If you said here is your old gearbox back with no judder, I would be 60:40 against this as the closer ratio gearbox is so much better once the car is moving. I suppose what it really needs is the gearbox I have with an extra gear below my first with a similar ratio to the standard first gear. Maybe on the new Esprit if it ever happens....?

Edited January 18, 2009 by toyroom

[M3S2k]

I have the same issue with my clutch Minus. Started 2 weeks after I rebuilt the gearbox from a broken differential. It was very pronounced when it started this and now happens all the time from a dead standstill. I will be removing the gearbox again in the next couple of weeks to either rebuild or replace the clutch to resolve this issue.

[mike_sekinger]

I would like to bring this back to life, since I recently bought the car from Nicolas.

Shuddering doesn

[andydclements]

I think you need to see what is happening when pulling away. Mate with a video camera or rolling road?

[Günter]

Mike, you're such an handy type of guy: just undo the rear luggage compartment panel and fit an ordinary digital camera on video-mode with tape on the battery holder. Wouldn't that do the work like Andy suggests...

[Lotuson74]

Dave and Mike, you guys are the best!! Exactly. Both of you got it right as has been my experiance also. Hold it at idle and it is possible to slip plate 1 (without "shudder") or increase revs then immediately at the same time release both the clutch and throttle (should be no shudder)

You can also give full throttle & "slip" the clutch's 2nd plate (maintaining approximately 6000 revs.) This also gives no shudder in my experiance - it might reduce clutch life however & make pulling into the garage. . . well, difficult.

[Zhastaph]

I had to replace both gearbox mounts on mine as the metal sleave had completely torn itself out of it's rubber mount. It looked ok to the eye, but was reasonaly obvious if you prized/lifted the gearbox up whilst looking at. I was suffering from quite bad clutch at the time also, though I cant recall well enough now which I had decided probably came first {ie the judder or the torn mount}

[toyroom]

Right, here is something else to consider: Coefficient of friction factors are what cause glass to squeak as you drag a finger across its surface. The squeak is the glass version of judder. If the judder is from the clutch, I would expect it to change under different conditions. My judder is definitely better in warm and dry environments (Summer in Liverpool) and worse on cold or wet days. It also gets worse as the clutch warms up such as moving about a car park or traffic line. The judder occurs just before final uptake of the drive (last 10% of pedal travel) and at more or less 1400 revs. For all these reasons, I deduce that all cars have some clutch judder and mine is more obvious due to the wacky gearbox I've got. Dave's car has the same judder on a standard 'box but much less obvious.

If your problem was mechanical such as something a bit bent like the flywheel not running completely true or the mounts gone, surely the problem wouldn't change with the weather. If your problem varies, it's probably not a loose thing and more likely a friction thing.

I hope this logic helps and be aware, I have replaced the clutch three times and the flywheel once with all new factory parts (and done at the factory) and it made no difference at all. The factory transmission guru agreed totally with the first paragraph above.

With regards to the engine mounts etc, just leave the engine cover off and look in the mirror (or over your shoulder if it is safe to do so) (find a big empty car park) You'll be amazed (and shocked) how much the engine moves even with all new mounts. It does move less with new ones however.

As an aside, this business of one of the clutch plates closing before the other can't be completely true as the two friction plates cannot move independently of each other because they are both splined to the same shaft. If the car is in gear, nothing at all moves beyond the flywheel and cover until the back wheels move. As movement increases, slip between the flywheel and friction plates decreases, (as the clutch engages by closing) but due to the above fact, the slip must always be the same for both plates. Doesn't mean that the clutch isn't holding the first plate tighter, but both plates must slip at the same rate as they are rotationally locked together.

[ricky]

Not sure if im way off the mark or whether this is relevant, but something as simple as tyre preasure can cause all sorts of problems with diff, drive shafts and box.

If there is a difference in preasures between the two rear tyres - ie, one is too low then problems can occur. I believe some rear engined cars are more sensitive to this than others. I have experience with X19 and early 911 where drive shaft uj bolts loosened all by them selves due to this !

If this is the case it could be the diff complaining as if the rear tyres were different sizes.

As I say, I may be way off the mark - just a thought. Perhaps check your rear tyre sizes and preasures.

[mike_sekinger]

Update on this one.

I have the car with me in Northern Germany, but with very little in the way of tool and facilities it is rather difficult to DIY it. After a very generous offer of help from locally based Berliner, G

[Günter]

\\\"easy peasy\\\" as you said 644km on the road, for 1 1/2 hour work (it is no problem, as long as you will pay my fuel ... . Maybee i have got an speeding ticket too, bud thats my game . Mom is only worried about fuels.. . Is a bit more than i need for the distance, the rest of the bill is my fee ) http://www.imagenetz.de/f52b124e1/R-ckfahrt.wmv.html

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Next time we will need: paper tissues and brake cleaner ,to clean the flywheel surface, clutch surfaces and the splines of the driveshaftends. We will need some adhesive to seal the driveshaft splines (simple *hylomar blue*, or something, you can imagine -i have it in my car.. .) . That way you do not need new o-rings and we\\\'re on the save site. With the old paper tissues we can than cover the gearbox driveshaft ends from dripping oil out next time we lift the gearbox in.

And most important, as it is an twin-plate -> an good aligning tool to match both friction plate spline centers all together.

Edited March 23, 2009 by G

[mike_sekinger]

Hi G

[M3S2k]

glad to see you guys made quick work of that clutch removal. All looks too reminiscent to me. Clutch looks in similar shape to what mine looked like when I pulled it out. I must say that transmission looks extremely cherry! Lot cleaner than mine did, haha. Where is that suspension link that you guys undid to swing the suspension out? I always undo the one right above/behind the disc and simply pivot the disc outwards.

Steve

[redshift]

just under 90 minutes !

Can only say that the evidence and the described symptoms align perfectly.

So you've got yourself another V8 then Mike? Are you going to import this one into France?

[mike_sekinger]

Yes - this one is coming home to France

I needed a car to test/run my engine builds and this one was being advertised at a very keen price.

It had a fresh engine (only 3K miles) and is a nice colour combination, although not the most cosmetically perfect example.

Hope to have it back in home for Easter.

Cheers,

Mike S

.. Where is that suspension link that you guys undid to swing the suspension out? I always undo the one right above/behind the disc and simply pivot the disc outwards.

Hi Steve,

We removed the links immediately adjacent to the lower chassis hoop. It is necessary to increase/reduce the lifting load as the chassis looses stress and flexes.

It is a hell of a lot easier with two people

Cheers,

Mike S

[Günter]

in such cases i undo the lower (long) suspension link, as i wanted to place the car again on its own wheels. Without to undo the wheels to get access in the wheelhouse/or undo the rear wheels from the hubs. It's fast an easy if you have not much time to pull the box out. And as i have told Mike later -we will need a lot more time to realign shafts, suspension links and clutch on the refit anyway !

Yeah-good thing really was that the engine is not original (as it was out/rebuild) -so the treats on the bolds did not have much rust on it, was just a little tight to remove the pre-set torque bolds with simple spanners and wrench

Edited March 24, 2009 by G

[M3S2k]

which pre-set torque bolts are you referring to Gunter?

For my alignment, we simply took the measurements of the spigot bearing and the tooth to tooth distance of the friction plates and machined a bar to fit both. Then drilled a couple of holes into the bar and hammered in some nails and ground them down into the shape of the splines. Took about 30 mins to make and worked perfectly.