Flipping the UN1?

[Danny]

Has anybody run the Renault box upside down and are there any issues to watch for?

 

[Stephane Goria]

Yes...

The lubrification system is an half bath, basically the secondary shaft stands fully under oil and brings lubrication by splashing the primeshaft.

Inverting this :

The primeshaft will be then under oil and the secondary over. The primeshaft pinions are smaller than those standing on the secondary, so the splashing capacities will be reduced.

Also it means that the shaft handling the more torque (secondary) will be out of oil, hence the bearings will meet very poor lubrification.

Also expect a lot of leaks, from the rear cover, and into the clutch.

Greetings

Stephane

 

[Geert-Jan]

Why do so.....?

 

[Mick Ridley]

To Get the drive shafts, higher

 

[Brian Magee]

.....and the engine lower.

You need to speak to Chris Cole who advertises in the GT40 Enthusiasts Club magazine.

Brian.

 

[Kev Farrington]

Hi, I flipped my Renault box many years ago so I could lower the engine and still retain sensible driveshaft angles. I wrote articles about it for the Enthusiasts club and the GTD club. It was over 20 years ago and its still working fine. Kev Farrington

 

[Danny]

Thanks guys.

I'll be using the diesel input shaft so that should get around the potential oil leak problem.

Kev have you done anything to improve the oil supply to the secondary shaft? How many miles have you done on the engine in those 20 years?

 

[Kev Farrington]

Hi Danny,
I originally had an oil pump feeding various parts of the box with a stat and cooler but to be honest it wasnt needed for the driving I did and I removed it all. The only problems I remember that related to it being inverted were the breather chucking oil out till I got the position right. I havent done many miles actually, still not reached 5000 yet, but I think serious faults would have shown up by now. Kev

 

[Stephane Goria]

Yes, speak to Chris. We share a lot about UN1 parts and improvements, specifically onto high friction synchro rings for 1st/2nd gear currently under production : higher friction = quicker shifting

To be mor eprecise, even if Kev did it...The front bearing of the secondary shaft MUST be bathing into oil. It is engineered in this way (roller bearing with extra large roller clearances for oil bathing). Keeping it out of oil, will drive soon or later into issues. Also the front bearing is not more available (only 5 are already available from SNR last year..).

This being said, if you do not intend to drive hard or to keep the same gearbox for years...all is possible even not having oil in the gearbox at all...;-)

Stephane

 

[Danny]

Hmm, more to think about than I hoped. Thanks for the all the advice so far.

 

[Cliff Beer]

Why? Do you want to go in reverse really fast??