Bora - clutch/engine vibration

Ivan,

I have not noticed that in my car. I will pay closer attention to that this weekend and check back in later.

 

Hi Ivan...

Could it be the bushings or motor mounts, or similar, that attach the engine to the
engine subframe?? Perhaps these are shot....

Mike

 

Hi Ivan,

Is this the same Bora you had clutch-problems with earlier?
Normally this is associated with shot mounts, but more likely your clutch is contaminated with oil.
The latter can sometimes be cured by spraying some degreaser on the plate (long thin tube, clutch dis-engaged), but if you have a source for the contamination, this will cure it only temporarilly, and it is a little 'shade-tree mechanic-ish " Don't over-do it, you don't want to wash the grease off the splines.
Of course the right way to do it is confirm the integrity of engine and gearbox mounts, and if OK, take the clutch out.

Best,

Jack.

 

I've never heard of this as you describe it.

So it only does this as you let out the clutch?

Or it happens after you let out the clutch gently in 1st and then accelerate hard?

The engine mounts are those big Vibrachoc spring units up front and the rear is that rubber piece involving the short metal cross bar.

Ivan it's been a long time since I touched the Vibrachoc units on my Bora but I recently had to refurbish smaller ones used for exhaust mounting on my Espada and those were adjustable in tension.

If you run the Bora sans cover you can observe the engine bobbing (no pun intended) around a bit. Maybe yours is too loose up front or something?

You could remove #40 in this diagram and see if the rubber has deteriorated. Mine got used a fair amount in hot environs and I've never experienced what you're talking about.

http://www.eurospares.co.uk/userImages/117/Large/117_016.gif

CV boots intact?

 

While we are at it, does anyone have a source for new #40's as many of them are certainly getting on in years.

 

I haven't ever looked into that but once the proper material is figured out I think a mold certainly could be made and a small run of these could be fabricated. That sort of thing is being done all the time now. It would be great to find an NOS version and check the durometer reading of the material.

 

With respect to the Vibrachoc stuff I found this today:

http://www.vibrachoc.es/pdfs/suspensionesmetalicas.pdf

 

Have you checked to make sure the carbs are synchronized properly. This will cause the engine to accelerate roughly from idle. Hows the timing? My Bora runs smoothly never had this problem.

 

I don't have this problem in my Bora, but I've had a similar problem in two other cars with this type of CV joint. I'm assuming that you don't have the vibration at the same engine speed and/or throttle position in other gears.
In cars with high mileage (or less if the CV joints have dried-out grease - more likely with a Bora) and not much drive shaft angularity, the six driving balls begin to wear a groove in their races because they always run in the same place. Under hard acceleration, the car squats and the torque applied to the half shafts is greater due to the multiplication of the low first gear. That causes the half shaft to snap back and forth as the balls are forced out of the worn groove. I had this problem in both a VW Camper and a Porsche. The VW was definitely not high performance, but it had been driven lots of miles. It became so severe that the shaft would slam into the hub and differential output flange. If the half shafts are the same length (they are in a Bora), a quick fix is to swap them side to side. That moves the wear point to the other side of the ball race, which has been used only in reverse.

Unlikely, but it fits the symptoms and it has happened on other cars.

 

Looking at the parts page that Roberto posted it shows the engine carrier mounting pads #27. Is anyone aware if these are available.
http://www.eurospares.co.uk/userImages/117/Large/117_016.gif

 

Took my Bora out today to checkout a local F-456 for an out of state F-chatter. I had this thread on my mind the whole time. I did not notice any unusual vibration other the the normal engine bobble Bob described. The again, I just replaced every bit of clutch mechanism there is.

 

Shssssh, don't tempt fate and no there's more you haven't replaced.

 

Staatsof, nice find on the enginemounts!

Kind regards

Kim

 

Good morning Ivan, et al.
Looking and re-reading this thread for the Nth time, I believe this problem occurs on mine. I'd describe it as excessive drivetrain "shudder" or "jounce" upon launch from a standstill, which goes away once the clutch is fully engaged and the car is underway.

My observations are;
- I can affect the amount of 'shudder' by modulation of clutch pressure.
- I can eliminate the 'shudder' my increasing engine RPM just a tad during launch.
- Aggressive launches do not suffer the 'shuddering' problem.

As a potential insight; I had the same "launch shudder" problem in a 1985 Honda Prelude where the cause was found to be out-of-spec vibration dampening springs within an aftermarket clutch plate which created a harmonic vibration when engaging the clutch. Replacing the aftermarket clutch plate with an OEM Honda part solved the problem in that case.

- My position is if the "shudder" always stops once the clutch is fully engaged, the engine/tranny mounts are NOT the likely problem.
- Aggressive launches compress the clutch dampening springs completely and deprive them the ability to set up harmonic vibrations.

What are The Forum's collective thoughts on the above?

Do you have records of a previous clutch replacement?
Are there known visual distinctions between an OEM Bora/ZF clutch plate vs an aftermarket replacement clutch plate?
Any idea what mileage a clutch plate typically endures before replacement?

I'm curious what the status of your effort is.
Best,
- Art

 

Dean, where did you or your shop source the clutch plate from? Are there by chance any photos of it?
Cheers,
- Art

 

Back in the day ... it was a Jag V12 clutch. I verified this at the Maserati & Jag dealer parts counter one day in SF.

I think the PP is the same as some Chevy V8 too?

 

A friend stuck a Jag plate in an Indy a couple of years ago. Perfect fit.

Best to look at part-numbers on the centre of the disk and the pressure plate.

For my Jags I used to get the disks re-manufactured and the pressure-plates surface-cleaned and re-shimmed to spec. Never had a problem.

Best,

Jack.

 

Here are the interchange listings.
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Art,

All the new clutch parts I installed came from MIE (maseratinet.com). You can buy individually or as a full kit.

 

I did not photograph it before install but their site has pics of the parts

Maserati Club, Maserati Parts, MIE Corp. MaseratiNet Store - Clutch & Hydraulics