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#1 Diff ratios
Posted: Wed Oct 31, 2012 7:18 pm
by david muir
What diff. ratio was the most commonly fitted , from new, in the 3.8 series?
I was led to believe that my 3.31 was but I hardly see this ratio mentioned on here.........is it unusual?
David
#2
Posted: Thu Nov 01, 2012 5:23 pm
by christopher storey
No, 3.31 was standard for most if not all RHD road cars up to about 1964 when I think a few had 3.07 just before the 4.2 was introduced . However , virtually all N.American cars had 3.54
#3 Diff ratios
Posted: Thu Nov 01, 2012 11:46 pm
by buchies
Hi All,
What is the easiest way to determine what diff ration is in place on my car?
Thanks
Philip
#4
Posted: Fri Nov 02, 2012 11:47 am
by christopher storey
Attached to one of the backplate bolts should be a tag with two numbers on it which represent the teeth on the crown wheel and pinion. Thus 3.07 is 43/14, 46/13( I think ) is 3.54 and 43/13 is 3.31. If the tag is missing then you will have to resort to counting revolutions of the propshaft against several revolutions of a roadwheel
#5
Posted: Sun Nov 04, 2012 5:41 pm
by graemea
Hi
No need to get under the car.
Just look at your speedo and compare the numbers to this list:
http://www.e-type-online.de/xkeratio.htm
Regards
Graeme
#6
Posted: Tue Nov 06, 2012 1:02 pm
by buchies
That's very useful thank you for that.
#7
Posted: Tue Nov 06, 2012 3:49 pm
by christopher storey
Unfortunately, Graeme's advice presupposes that neither the speedo nor the axle ratio have ever been changed during the car's life. Whilst in New Zealand that may be the case, many cars found in Europe have a colourful history with many parts substituted .
#8
Posted: Wed Nov 07, 2012 10:24 am
by buchies
christopher storey wrote:Unfortunately, Graeme's advice presupposes that neither the speedo nor the axle ratio have ever been changed during the car's life. Whilst in New Zealand that may be the case, many cars found in Europe have a colourful history with many parts substituted .
Hi Chris
You make a valid point. My car seems to be unmolested and I was keen to use this as yet another test to support my theory.
So far so good.
Regards,
Philip