Fiat Dino 2400 Coupe - drivetrain vibration

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abarth4
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Dino: Fiat Dino 2.4 Spider
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Re: Fiat Dino 2400 Coupe - drivetrain vibration

Post by abarth4 »

Hi Bijan
Yes, the engine mounts can be changed with everything in place. It is tedious but it can be done. Also, the short driveshaft section can be balanced out of the car. I have had that done as well. See my previous posts at the beginning section of this thread. Balancing the short driveshaft had the biggest effect for me. Based on the many posts for this thread, this is a problem area on the 2.4 liter cars. It is apparent that it is a very sensitive area since there have been many good suggestions in this thread. It all has to be right for things to work in harmony!
Charlie Bates
Metamora Illinois, USA
Fiat Dino Spider 2400 #1186
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doublegarage
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Re: Fiat Dino 2400 Coupe - drivetrain vibration

Post by doublegarage »

Hi Charlie - I think Bijan was referring to the rear axle driveshafts (half-shafts) when referring to the "short" shaft.

I agree that the short central driveshaft could be balanced alone but would recommend (as others have on this thread) that as much of the shaft as possible be balanced as a single system - that was what finally solved my problem - although..I am fairly sure that the main issue for me was the crazy weight someone had welded to the short shaft.

-Richard
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Dinofanwim
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Re: Fiat Dino 2400 Coupe - drivetrain vibration

Post by Dinofanwim »

Hey Bijan,
Please note that if your drive shaft lay-out from where it leaves the gearbox all the way up to the differential should be as straight as possible, so if the support brackets from the joints, engine brackets and the rear axle are not as it should be, your drive train is not straight enough and you might end up with vibrations.
If you were to have universal joints installed, the problem would not have occurred so much.
Furthermore it is obvious that good balanced drive shafts are an absolute must.
Although I am nowhere near that part of doing up my Dino's, it seems to me that this is just a straightforward part of engineering.
I could also be that something is not right with your LSD, but that seems less likely!
You also chechked the rubber spider joint?

Hope that this will contribute to solving your problem.
La passione per tutti creazone!
Alfre"dino", che significa tanto a suo padre Enzo!
Poi ha lanciato suo padre Enzo, il marchio "Dino".

stratos
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Re: Fiat Dino 2400 Coupe - drivetrain vibration

Post by stratos »

abarth4 wrote:I fought a similar driveline vibration on my car for a long time. It ultimately turned out to be the balance of the short driveshaft that is between the rubber flex disc and the torque tube. It took a couple of different places to run it across their balancer before I got on top of it. I wrote an article about it... I'll have to see if I can find it and figure out how to post it up here... :? However, take a good look at your motor mount brackets. They are made out of fabricated sheet metal that is folded and spot welded. They are the same part on both the 2.0 and 2.4 liter cars, but I have found that on the 2.4 they can fatigue and start to crack. Maybe because the 2.4 engine is heavier? At any rate, I had mine cut and refabricated which kept the engine from dropping (slightly) and putting the driveshaft out of alignment. Hope this helps.
Charlie Bates
2.4 Spider #1186
Hello,
I've read in a old post you had a SPYDER hard top for sale.
Do you still have it ?
Thank you.
Luis A
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Dino: Fiat Dino 2.4 Coupe

Re: Fiat Dino 2400 Coupe - drivetrain vibration

Post by Luis A »

Hi all, I am pulling this thread back up since I have had a vibration in my Dino 2400 but only under very specific conditions. A lot of good information here.

However, I *only* get vibrations when accelerating hard from a stop under load. It never happens at speed, only under heavy load when accelerating from standing. That is not what I read about Richard or Georg having trouble with but rather vibrations at specific RPMs, which I don't have, all the way up to 5,500 RPM and 95 MPH; no vibrations...

I have not yet investigated the spherical bushing in the front of the driveshaft but I did grease it but not sure if the previous owner did.

Georg, was your vibration under heavy acceleration from standing, like mine?

Richard: How about yours? Did you resolve it?

Luis
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doublegarage
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Re: Fiat Dino 2400 Coupe - drivetrain vibration

Post by doublegarage »

Hi Luis,

Sorry to say I don't think my car's vibration was similar to yours. Mine was most noticeable when coasting, allowing the wheels to drive the shaft in effect.

The fix was to remove some crazy weights that had been welded to the front of the solid shaft inside the front of the torque-tube - and then to balance as a system. I was lucky to have someone nearby who took it as a challenger to build some adapters so he could spin my shast at high speed while it was assembled.

Please let us know what you fond.

-Richard
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