Engine/gearbox mounts for QP

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ChrisNico

Member
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171
BTW, I hope to meet some of you crazy people at the Brooklands Auto Italia gathering this month. It has been a long time since I attended. I should be ashamed seeing as it was my SZ that featured on the very first issue Auto Italia published :)

IMG_5695.jpg
 
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ChrisNico

Member
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171
It was an outrageous looking car back in 1990 and I guess it has aged very well, BUT I miss my GTV6 more - maybe because the SZ was so easy to drive quickly, and incredibly forgiving, whereas the GTV6 was a real challenge :)
 
voicey

voicey

Member
Messages
660
ChrisNico said:
Good morning Voicey,

While there has been a significant reduction in vibration since fitting new engine mounts, is the vibration I'm still feeling at high revs due to clutch/gearbox or propshaft?

Thanks,

~C
Click to expand...

It could be a number of things. What have the people who did the mounts say?
 
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ChrisNico

Member
Messages
171
voicey said:
The propshaft shouldn't be turning when the car is stationary - it is decoupled from the engine by the clutch.
Click to expand...

Ah yes, unlike the Alfa GTV6, the clutch is at the front. The garage said nothing. They merely changed the mounts for me. I think I need to drive another QP to see if I'm being too fussy about the vibration...
 
Mr K

Mr K

Member
Messages
321
voicey said:
The propshaft shouldn't be turning when the car is stationary - it is decoupled from the engine by the clutch.
Click to expand...

Surely it will be turning with the clutch engaged and the 'box in neutral? Obviously when in gear and the car's stationary, it won't be spinning.

ChrisNico said:
Ah yes, unlike the Alfa GTV6, the clutch is at the front. The garage said nothing. They merely changed the mounts for me. I think I need to drive another QP to see if I'm being too fussy about the vibration...
Click to expand...

Both my QPs have been super-smooth, at all speeds. There's scope for fitting the clutch incorrectly, causing an imbalance - that's what my money's on.
 
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ChrisNico

Member
Messages
171
Mr K said:
Surely it will be turning with the clutch engaged and the 'box in neutral? Obviously when in gear and the car's stationary, it won't be spinning.



Both my QPs have been super-smooth, at all speeds. There's scope for fitting the clutch incorrectly, causing an imbalance - that's what my money's on.
Click to expand...

That's a good point Mr K. I guess the control system depresses the clutch when you put your foot on the brake, no?

If you're right and it's a clutch imbalance, that sounds like an expensive adjustment. Just when I thought I was almost done for a while...
 
voicey

voicey

Member
Messages
660
Mr K said:
Surely it will be turning with the clutch engaged and the 'box in neutral? Obviously when in gear and the car's stationary, it won't be spinning.
Click to expand...

Yes, if the box was in neutral and the clutch was engaged the propshaft would be spinning. However this scenario never occurs as the TCU holds the clutch at the PIS ready to engage a gear.

To be 100% pedantic about it, there is a brief moment when the engine is first switched on that the TCU commands the clutch to kiss the flywheel in order to calibrate a number of parameters. This will cause the propshaft to spin but it is only for a very short peroiod of time. Even if you could catch it at this point, it would be pointless revving the engine as the TCU would cancel the calibration and open the clutch.

Obviously if you had one of the rare manual versions it would be possible to do the test as you describe...
 
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ChrisNico

Member
Messages
171
voicey said:
Yes, if the box was in neutral and the clutch was engaged the propshaft would be spinning. However this scenario never occurs as the TCU holds the clutch at the PIS ready to engage a gear.

To be 100% pedantic about it, there is a brief moment when the engine is first switched on that the TCU commands the clutch to kiss the flywheel in order to calibrate a number of parameters. This will cause the propshaft to spin but it is only for a very short peroiod of time. Even if you could catch it at this point, it would be pointless revving the engine as the TCU would cancel the calibration and open the clutch.

Obviously if you had one of the rare manual versions it would be possible to do the test as you describe...
Click to expand...

That makes sense judging by the speed of gear engagement. So, if I experience vibration in neutral, it points to a clutch imbalance. If only under load and in gear, it's a propshaft issue, yes?
 
rs48635

rs48635

Member
Messages
3,181
was just heading outside to view the propshaft with engine running and car stationary.
It's not there , away getting new rear bumper fitted. Doh!
 
Mr K

Mr K

Member
Messages
321
rs48635 said:
was just heading outside to view the propshaft with engine running and car stationary.
It's not there , away getting new rear bumper fitted. Doh!
Click to expand...

Just as well you didn't find it there as you can't see whether it's spinning because it's enveloped within the torque tube :)
 
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ChrisNico

Member
Messages
171
As I previously mentioned, the vibration is far less since the engine mount replacement. I investigated further today. Seems there is some resonance around 3,000 rpm which smooths out as you go higher, but there is always some vibration. It seems very slightly worse when under load, so I guess it must be a clutch imbalance issue. I guess the only way to know if it's worth investigating before a necessary clutch change, is to experience another QP that is 'vibration free' :)
 
martininkent

martininkent

Junior Member
Messages
137
anyone buying engine mounts for a QP , i found scuderia the cheapest for the mounts,
and there are 2 different types, they are different if you you have a DS as opposed to a ZF.
ding mine this weekend,
just some info
 
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stef4u

New Member
Messages
11
perhaps checking the brake discs at the front would surprise you
if somewhat curved at either side can cause a wobble (as I learned on a v8 bmw after replacing like complete suspension arms etc)
 
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