1750 differential

[AlfaNeely@domain.elided]

       I do not know why anyone would want to put a 1750 rear axle in a 1984 
spider.  The 84 already has a 4.10 ratio, plus the 84 has limited slip.  The 
1750 had no limited slip, plus I understand the axles are slightly smaller.  
If you want a 4.56 get a spider rear axle between 1972 and 1980, which will 
also have limited slip.
       I mark both rear wheels and the driveshaft or yoke.  Turn both wheels 
exactly one revolution and count the number of times the driveshaft / yoke 
turns.  It is accurate enough to determine a 4.10 ratio from a 4.56.  If you 
want more accuracy, turn the rear wheels 10 revolutions.
       The Alfa limited slip is a stack of driven and undriven disks.  There 
are no springs or other devices to tension the stack other than the installed 
height of the stack within the case.  To tighten the LSD, cut shim stock and 
fit it at both ends of the stack.
       The reason you cannot determine a LSD rear end by jacking up one rear 
axle is wear.  Any Alfa with a LSD that has 10,000 or more miles will have 
enough wear on the clutch stack to act like an open differential.
       There are some ramps in the Alfa LSD that theoretically apply pressure 
to tighten up the clutch stack.  However, the ramps are not very effective in 
my experience and work only when both rear wheels have resistance on them.  
That is, the ramps will not help if one wheel is on ice or is lifted from the 
track in a tight corner.
       So just put enough shims in the rear end to make it effectively 
locked.  Then do it again every year or so.

Ciao,
Russ Neely
Oklahoma City


In a message dated 09/23/2002 7:43:47 PM Central Daylight Time, 
owner-alfa-digest@domain.elided writes:



> 
> Date: Mon, 23 Sep 2002 19:41:59 -0400
> From: "Ed & Marsha Prytherch" <mred2u@domain.elided>
> Subject: 1750 differential
> 
> I just bought a 1970 Euro 1750 spider parts car. The axle ratio is 4.1:1.
> There is an easy way to find out what you have:
> Jack up one rear wheel. Position yourself so that you can see the flange at
> the rear of the prop shaft. Turn the rear wheel exactly 5 revolutions and
> count how many flange nuts go past a fixed point. Divide that number by 10
> and you have the ratio.
> 
> And now a question for the experts. In the Autobooks manual for 1962-1978
> Giulias, is the following - "The propeller shafts on vehicles equipped with
> limited slip differentials cannot be turned with only one wheel clear of the
> ground as with conventional differentials." It goes on to warn about driving
> the car off the jack stand if the prop shaft is forced to turn with one
> wheel on the ground. Both my 1973 GTV and my 1979 spider allow the prop
> shaft and the raised wheel to spin freely. Are my LSD differentials now
> unlimited slip or is the book incorrect?
> 
> Ed Prytherch
> 
> "Anne O"  wrote
> >Next transplant candidate-the differential from a 70 Euro 1750
> into a 84 Spider. Does anyone know definitively the ratio of
> the 1970 1750 Euro GTV?Is it easier to swap out the entire rear
> suspension? To the best of my knowledge,the transmission is a
> straightforward swap-opinions?
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