24V V6 Duel mass flywheel and diff Failure

[alanm]

Hi all,
I have been doing some research into the 916 series GTV V6, 147 GTA and GT 3.2 tring to get an understanding of cost of ownership, particularly the 'must do' maintenance and modifications. If I buy one of these cars I want to be able to use its full potential without fear of breaking something.

I thought I had it all worked out - replace the cam belt, tensioner, water pump etc if due and fit a Q2 diff. Then I started reading about the duel mass flywheel fitted in S1 and S2 GTV's.

There is some suggestion in forums that there might be a correlation between solid flywheels and diff breaks because there is less 'give' in the driveline. The implication of this is, if you replace a DMF on a GTV with a solid flywheel and GTA clutch (to avoid DMF failure) you better get a Q2 at the same time!

My specific questions are:
Does anyone know of a diff failure on a 6 speed GTV fitted with a DMF?

On a 10 plus year old GTV with a OE clutch and DMF that operate okay could i just replace the cam belt and assoc bits and enjoy, or do I need to budget for solid flywheel, GTA clutch, Q2 diff and cambelt?

The easy way out would be to buy a well maintained GTA or GT with Q2 but I have a soft spot for GTV's. S3 GTV's with solid flywheels and GTA clutches are a little thin on the ground.

I think I have researched myself to a standstill 

Cheers,
Alan

[Craig_m67]

I'd budget for a Q2, everybody says it transforms the GTA, must help on a GTV.
If it was me and the DMF was no good I'd simply ditch it and use the 3.2 setup.

I have a 1.9JTD (156) which uses a DMF.  I've replaced one clutch, the DMF was retained as it seemed fine. If it ever does go pear shaped I will go back to a standard flywheel (like most all other DMF users (VAG, BMW, FIAT) in the UK and EU).

[TFJ100]

I had a Phase 2 with a standard flywheel set up and received a broken diff....back in about 2008.

Is this what you are asking?

Replaced the diff with a Q2 and it was fine after that.

Cheers
Torben

[colcol]

If Alfa Romeo and other car manufacturers fit Dual Mass Flywheels at greater expense, there must be a reason for it, if the cost cutters could shave .1cents off a washer they do, they could save hundreds of dollars by fitting normal flywheels, then they would...except it wouldn't do the same job of smoothing out the power flow to the driveline, on diesels the Dual Mass Flywheel stops the gearbox gears from rattling against each other causing wear and noise.
Ford in the UK, said the Dual Mass Flywheel made diesels acceptable to Female car owners, who liked the refinement offered by the Dual Mass Flywheel.
A large Australian parts retailer offers conversions back to solid flywheels, which may be acceptable on a work ute, but the lack of refinement would sure start to drive you mad in an Alfa.
Sure the Dual Mass Flywheels are dearer than a solid one, but you are driving an Alfa, not a 20 year old paddock bomb, be carefull of changing from what Alfa had intended, as you will cause other unwanted problems, Colin.

[scott.venables]

G'day Alan.

To me a DMF is a modern thing solely for reducing NVH, and I can't really see how it could have much impact on a diff on the other end of the gearbox. The GTA, despite having more power doesn't have one, presumably because it's not expected to be 'refined'.

I would be more worried about the GTA flywheel having the wrong counterbalance for a 3.0 or 2.5

Cheers , Scott

[colcol]

The dual Mass Flywheel smooths out the power flow to the gearbox and final drive, rather than having a pulsing going through the input shaft causing the gears to rattle, it smooths out the power flow.
Try and stick with what the manufacturer had there originally, as it would all be tested and balanced, if you change something it would best to get the crank and flywheel and harmonic balance balanced as a unit, Colin.

[alanm]

Thanks for your responses everyone, all useful insights.

Torben, your first hand experience with a diff break in a car with the DMF confirms that the solid flywheel set ups are not the only ones that break diffs (though they might be more common). Maybe this is more related to the greater power/torque of the 3.2, or the driving style of the GT/GTA owner!

Cheers,
Alan

[Domenic]

I received the new edition of The Automotive Engineer magazine in the mail a couple of days ago and came across an interesting article about Dual Mass Flywheels.

Thought I'd post it to help people make an informed decision on the matter.
See the below attachment. (hopefully it they work)

[colcol]

Good article Domenic, gear sets for Porcshe's are about $1300 per set from Porcshe Australia, what would they be for an Alfa Romeo?, who would know after they have been destroyed by fitting a solid flywheel, instead of a Dual Mass Flywheel, still cannot beleive i saw an article on replacing your worn out Dual Mass Flywheel with a unapproved by the carmaker, solid flywheel from a major Replacement Parts Company in Australia, thought it was just for tight ar5es, trying to save a few $$$, it is something that would come back to bite you, Colin.

[Domenic]

Hey Colin,

I'm guessing a gear set from Alfa won't be cheap, especially for a V6 gearbox. To rebuild a standard 4cyl gearbox with new gear set/synchro's and diff pin (shitty hardening from factory that's why they break) you'd be looking close to $3k or maybe more, and that's not skimping on any parts and doing the job properly.
The V6 gearbox i can only imagine it would be close to double that all for the sake of a few hundred $$$ on a flywheel, then plus the labour to do it all over again. I just don't think it would be worth it at the end of the day.

[colcol]

If the Differential Pinions break, then they must be too brittle or not strong enough to do the job, if they are too soft, they will experience pitting, metal not hard enough, and wearing off,...just like the Albins Transaxles in the V-8 Supercars suffer from.
If one of the gears that fail are integral on a layshaft or countershaft, then imagine the cost of replacing that, the New Dual Mass Flywheel price looks like a bargain.
But if you like rebuilding gearboxes and waiting around for months for parts to arrive, not to mention the  embarrasment of having to be towed, then go ahead and fit a solid fltwheel, Colin.