Europa gearbox question

[Matt Elan]

Hi All

Back on writing my Europa book, and I'v got a slightly odd technical question. Renault altered the direction of rotation of the output shafts in their transaxle by moving the differential's crown wheel from one side of the gearbox's secondary (output) shaft to the other. Looking at various cutaways in the contemporary press reports the crown wheel is on the right hand side of the secondary shaft - thats looking forwards i.e. towards the engine. The Lotus part book also shows it on the right. The Lotus workshop manual shows it on the left.
Now having done some paper exercises to try to work out the various rotations of the engine to input shaft to output shaft to drive shafts I'm somewhat dazed and confused, but think the original Renault must have had the crown wheel on the RIGHT hand side of the pinion, and the Lotus had it on the LEFT hand side. Can anyone put me out of my misery and tell me if I'm correct?    Looking forward to  the answer!
Matt

[4129R]

All I know is the gearbox was in front of the engine in the FWD Renault, hence the wrong direction problem.

Not many people have dared venture into the mystery inside the gearbox casing, as spares for the Renault gearbox are very hard to obtain. 

I fear I may have to open one up soon. A bit like Tutankhamun's tomb in the Valley of the Kings, you just don't know what you might find when you open the box up.

[SwiftDB4]

Crown wheel is on the left on Lotus models and most later Renault boxes such as NG series because Renault went from engine behind axle to engine in front of axle.
Actually Renault boxes aren't that difficult to work on. Just don't lose the detente balls. The NG series is the easiest because the gears are held on by circlips and don't have to be pressed on and off.

[Matt Elan]

Thanks for that 412R - glad I'm not the only one puzzled! However, I've had a rummage on the Lotus-Europa site and found a R16 parts manual - and the gearbox in that book has the crown wheel on the right, so it looks like the Lotus version will have it on the left. And just as I'm writing this SwiftDB4 has confirmed this! Brilliant and thanks
Matt

[jbcollier]

The ring pinion are not run "backwards" on one compared to the other.  The 336 version for the Lotus had it's own ring and pinion gears.  You can find confirmation here:

http://www.lotus-europa.com/literature/Autoworld-Jan-Feb-1967.pdf

For the 352/365, the transaxle comes from the R17 which has the transaxle "behind" the engine, unlike the R16.  As it was already rotating in the correct direction for the Europa, no special ring and pinion were required.  However, this meant that the 365/5spd version would be slower as it had a lower final drive than the 336 version for the Lotus (3.5x compared to 3.7x).  Lotus had Hewland make up a custom 5th gear set to make up the difference.

[Matt Elan]

Thanks for the article - and it confirms that the crown wheel on the Lotus application rotates the opposite way to that of the Renault 16 application - and that, as you say, the Lotus has its own re-cut gears to raise the final drive from 3.77 to 3.56. 
Also, the cutaway in the article is of the Renault 16 application with its crown wheel on the right - its the same one used in a couple of other period articles. I guess Lotus didn't bother to change it but just used the Renault one!
Many thanks to all for the replies!
Matt

 

[jbcollier]

Renault did the revised ring and pinion for Lotus and supplied the transaxle ready to go.

The 1470 engines were from a run of unwanted marine engines.  They switched to the 1565 when supplies ran out.

Yes, the Renault 16 cut-aways were used in all the promo materials and magazine articles that I have seen.