POST 9 - JULY 2011 - GEARBOX AND AXLE RATIOS

Early 120's had ENV axles fitted instead of the Salisbury axle as fitted to my 140.  However, a little research indicates that the ENV unit is very robust and was fitted to Landrovers and some Armoured Cars.  I can only hope that it is in reasonable condition but will only really know on my first drive.  I would be happy to have it checked over by a specialist if could find one and be sure they genuinely knew their way around the ENV unit.

That old expression "In the land of the blind, the one eyed man is King" is, I have found to my cost on several occasions, very apt in the classic car restoration world.  How can I determine who really knows these units when I am clueless?

Two other advantages of the ENV axle are the apparent ease with which wire wheel hubs can be fitted and its 3.643 ratio. 

Some time back I was trying to decide the best gearbox solution for my 140.  The Moss Box was in a pretty bad state and the overdrive unit needed some attention.  After comparing specs for a number of different gearboxes I opted for a Classic Jaguar (CJ) 5 speed, based around the Tremec T5 WC (World class) unit.  The T5 unit with its 0.77 5th gear is excellent in the 140, but when coupled with the ENV diff will provide even better motorway cruising speeds nicely within the XK engine torque range.

 http://www.classicjaguar.com/  This is a brilliant site if you are not already familiar with it, mainly E types but XK's also, with literally thousands of detailed pics.

ENV Series One (JHS1398) Diff Label gives ratios as 14 / 51
which works out at 3.643  compared to 4.09 on the XK140







Spread Sheet originally written to compare XK140 ratios shows 120
 with ideal cruising speed of 73MPH at 2500 with CJ 5 Speed.  Perfect!