Re: [Amc-list] clutch questions (now speedo gearing)

[Frank Swygert <farna@xxxxxxx>]

The speedos both register left to right in early and late cars. The cable turns in opposite directions though. Obviously the speedometer heads are made differently, with gearing to handle the different cable direction. If you connect an early speedo head directly to a later trans the speedo tries to run backwards, which of course it can't do (but it gives a "firm" zero reading!). Been there, done that! Sensible or not, that's the way they did it. Turning backwards will damage the speedo head over time, done that too!! 

Remember, there's a gear drive in the speedo head, it's not directly connected to the cable. All the manufacturer had to do was change drive sides, the same as the input on the trans did. If you could move the ring gear on a rear axle to the opposite side of the diff without moving the pinion or changing the direction the pinion turned the axles (wheels) would rotate in the opposite direction, or you'd have one forward and multiple reverse gears. Porsche and Corvair transaxles and be "flipped" like that, so they can be used for mid or rear engine applications. 



----------------
Date: Tue, 16 Oct 2007 12:56:39 -0500
From: Peter Marano <PMarano@xxxxxxxxx>
 
Frank Swygert wrote:
One thing to note when changing trannys from pre 63 (64 American) and post is that the speedo turns the opposite direction. The speedo runs off the TOP of the driven ger on the tailshaft in early cars, bottom in late ones. The reason is that early cars are taller and have a shallower trans tunnel. 


Peter replied:
>>>>>This only makes sense if the speedo registers in the anticlockwise direction.


-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
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