131mirafiori forum

rubber donut or no rubber donut,
 this discussion started in the 131 gr4 in holland thread. in answer to the response to no rubber donut cause's the transmission to wear out quicker, i cannot agree. possibly you do need some sort of damper between the engine and the tyres say for noise insulation. But, you ony have to look at the number of propshafts on ebay for sale to see that its not the only way of make a propshaft. subaru's dont have one, neither intgrales and dare i mention them here escort mk2, and front wheel drive? 

i would be interested to see how walzey or toad approached it. it will be humble pie if mine lets go and i will let you all know.

cheers sach.   

I'd agree. Plenty of powerful sports cars that don't have rubber components in the drive train. The Fiat is the only car I've owned that isn't simply unijoints and splined shafts from front to back. I've never been kind on machinery and I haven't broken one yet, I have broken rubber donuts on the 131 though.

Rallying is expensive and "they" don't care much for expense. So, a drivetrain without any rubber components isn't a problem. It's all about setting the fastest time. Fiat however, always in search for low expense, made a durable system which was cheap and would last longer then one stage.

there you have it.
ok, i haven't tried running without donut but have found that original one lasts usually around 100k kms, and each one i ever bought as aftermarket part failed after 5k up to 20k kms. in the end i resorted to installing used ones from scrapped cars because i found that they usually last longer than new ones.
donut from scrapped 1975 fiat 132 is still on my twincam lada and going strong after 60k kms with much abuse, 120hp, 4.3/1 diff, 205 tyres and plenty wheel spins on dry asphalt, towing other cars, trailers carying 700kilo boat, 1000kilo cars etc.
i guess that not many cars go tru this kind of every day abuse. being a workhorse, and a car that i consider expendable, lada is possibly the car i might try this "no donut" solution on.

The donut is not only there for bringing down vibrations to a minimum, but also for the same reason why the clutch plate has springs. It's there for shock absorbing too. Hits from the engine are absorbed by clutch and hits from the gearbox are absorbed by the donut coupling.
Halfway down the propshaft there is another bearing. It's fitted in rubber. For same reason as the donut is.

AGREED..

I have never had a problem with the rubber doughnut on the 131's & 132's and I have always reused them and some of them did look like they were past their best.
On the other hand I once owned a 1973 bmw 520i ( the old 4 cyl engine) and fitted a new clutch and looked at the rubber doughnut on that and thought  "thats fine"  big mistake as two or three days later it disintigrated but then thats german rubbish for you !