Driveshaft question

[Alan Hopla]

On the weekend I was under the Alfetta and noticed I had a torn CV joint rubber boot, so out came the driveshaft and off to the shed for a spare.
Unfortunately all my spares are too long!
So back under the car and sure enough I have a top hat spacer bolted to the disk / output flange.

Now this transmission is of unknown and probably mixed parentage, but my understand was that these spacers were fitted to V6 engined cars, (eg GTV6  & 75), please correct me if I am wrong.

What is the preferred setup the longer shard or the shorter one?
And why is there a difference?
I thought maybe heat, to move the CV joint a bit further away from the disk.
But if this was the case why wouldn't you use it on all new models, (75TS used the longer shaft setup)?

I think I could use the longer shaft if I changed the diff output flange and the rear disk rotors (I assume that these have different size holes for the different mounting bolts M8 v M10 I think), then install the longer shaft.

For now I will just take the easy path and refit the short shaft, but am looking for input on what would be best in the long term.

Oh wise ones, thank you for your input.
Alan.

[Jekyll and Hyde]

Now this transmission is of unknown and probably mixed parentage, but my understand was that these spacers were fitted to V6 engined cars, (eg GTV6  & 75), please correct me if I am wrong.

Although all the V6's had spacers (of which there are two types of different lengths) they are different to what you have, as V6 CV joints are bigger than the 4 cylinder ones.  In the 4 cylinders, you had either the type where the CV bolts straight up to the disc, or the type with the spacer as fitted to your car.  Can't remember which is early and which is late type - 75 TS certainly has driveshafts bolted straight to the disc, but I'm not so sure that it's a 'late car' type thing, I have a vague recollection Alfa chopped and changed between the two types.

As far as which is better, for a road car it makes no difference at all.  In a race car, I have a slight preference for the type without the spacer, partly because it's one less set of bolts to vibrate loose (everything seems to be able to work loose under race conditions!), and I also feel they may be a little stronger without the cast spacer, but I have no 'test data' to prove that.  The flipside, as you say, is probably a little more heat in the CV off the disc.

Why not just fit a good CV boot off one of your spare shafts to the shaft from the car?

[Alan Hopla]

Thanks, as I said the short term plan is to refit the short shaft, (after replacing the boot).
In six 4cyl cars ranging from a couple of 77 Alfettas to 89 TS this is the first time I have seen these spacers. So I was a little surprised, and was just wondering what others thought was the better solution.

Thanks,
Alan.

[MD]

Alan

My view is very similar to Jekyll. l think early productions considered that the CV would benefit from some heat sinking but that was then later traded for perhaps less parts to stress,produce and fit and so cheaper to assemble etc.

Frankly I have used both and find no obvious difference between the the two. I also think the larger V6 CVs are over engineered as the 2 litre units have not failed from applied power considerably greater that the original power from the V6 engine.

[aggie57]

I also think the larger V6 CVs are over engineered as the 2 litre units have not failed from applied power considerably greater that the original power from the V6 engine.

Mmmm:

http://www.alfaclubvic.org.au/forum/index.php?topic=8880.15

Not uncommon with these cars.  Can recall a number of similar failures over the years.

[Darryl]

A US based alfa expert who is never wrong (yes that one - I'm really only citing a data point not claiming infallibility of source) agrees with MD (and uses the 4 cylinder CVs and shafts for V6 race setups). I don't think anyone is claiming that any CV joint lasts forever, though those on transaxle alfas do seem to last a long time - certainly compared to your typical fwd.

[MD]

aggie, just to clarify. I am not saying the V6 larger CVs are a bad thing. What I am saying is how good the 2 litre units are. And no, they dont last forever! I broke one on the Brick. The cause is still being debated.
Likely suspects are shock landings from kerb hoping and possibly how some dampers work (this was a prime suspicion of a Ford team that kept breaking CV's) bad lubrication, metalurgy blah blah and let's face it, nobody with a strong 2litre competition engine that makes more power than a standard V6 is ever going to consider going to larger CV's because they are simply going to go with what they have to start with anyway..if they do the job, why would you want to rotate more mass?