Gearbox prep'

[vernon.taylor]

Salut

I bought a nice looking 5-speed Lotus 'box from Gino. The insides look nice and crisp, but the remaining oil a bit watery and dark. After I drain the remaining oil, should I clean it out with something and what?

Also the gearstick has some vertical and side-to-side movement when in gear. A friend told me his 5-speed lotus 'box was the same. The only spring resistance is on O/D/Reverse. Is this indeed normal and is there anything to take up the slack?

Merci d'avance.

Vernon

[alexblack13]

[quote="vernon.taylor"]Salut

I bought a nice looking 5-speed Lotus 'box from Gino. The insides look nice and crisp, but the remaining oil a bit watery and dark. After I drain the remaining oil, should I clean it out with something and what?



The Lotus box should be run on engine type oils. A 20 -50 or similar. That's why your oil looks 'watery' The internals of the gearbox were designed and manufactured to run in BL vehicles. And started life in the 'Maxi' which had the gearbox on the bottom of the engine and was lubricated with the engines oil. Don't run it on Gearbox type oils. It will not like that much.

By all means give it a good clean / wash out, but if it were me I would have it checked out by an expert in the box type. Graham Boulton is your (ex Lotus Gearboxes) Man... He is THE Guru on these boxes.

Good luck with it. I am enjoying my 5 speed Sprint. What a difference the box makes.

Al' .....

[alfert]

I think you better check what oil you run in the gearbox....... Dave Bean Engineering in the states told me to be sure to run non synthetic 80 gear lube. I have never been told to run engine oil in trans. Just take a minute to be sure you want to do that
Brian

[reb53]

The internals of the gearbox were designed and manufactured to run in BL vehicles. And started life in the 'Maxi' which had the gearbox on the bottom of the engine and was lubricated with the engines oil.

Brian, Alex isn't suggesting all boxes should be run on the appropriate engine oil, just this one.

Ralph.

[rgh0]

The 5 speed box should be run on Redline MTL IMHO.

If the maxi box internals ran on engine oil originaly this was always a compromise of its orginal design installation in the sump of the engine and using Redline MTL will give an improvement in both gear change performance and bearing and syncro life for the Lotus application.

The Redline technical data sheets expand upon this issue and why you should use MTL in manual boxes where you can that were orginally specified for engine oil or ATF for a variety of reasons.

regards
Rohan

[alexblack13]

Yes. redline is the best...ONCE RUN IN. Don't try and run a box in with Red-line its way too good a lub'.. It is what's in my 5 speed and the difference when fitted was huge.

The main Gearbox specialist in the UK for this LOTUS 5 SPEED BOX..WITH THE MAXI INTERNALS. Is Graham Boulton. When he hands over a rebuilt 5 speed his recommended oil is a good 20-50. Lotus nicked the internals for the box from BL who used it in the 5 speed maxi. The box of course used (and was designed to use) ENGINE OIL. Graham is ex Lotus. Gearbox deptmnt.

80 -90 weight oils are for the Ford type boxes etc. NOT the maxi / Lotus box.

AB....

[jono]

think of the Maxi engine as a big Mini engine - come to think of it the clue is in the name

My dad had 2 Maxis -horrible things but used to swallow up our family of 7 and whisk us off to Scotland on holiday every year without a problem

[vernon.taylor]

Merci les gars

What about the slack in the gearstick - is that normal and is there something to do? Saw in the archives someone who fitted a quick-shift that improved feel, but it appeared to be a one-off.

@+

Vernon

[rgh0]

The gear lever has a rubber bellows "spring" that holds it in place in its ball joint as this looses compression over time the gear level gets loose. I have shimmed down the rubber spring from its top location circlip on the lever and that firms up the lever location. I suspect a redesign of this with a more rigid location would be beneficial but i have never had the time to pursue.

The various linkages from the lever to the selector forks also wear over time and examination of these and rebuilding as needed also tightens up the change. Compared to the 4 speed box these linkages are more complex and not so direct so wear results in more looseness in the change.

cheers
Rohan

[alexblack13]

Have a look at my escapades... Esp the gearstick mods.

Have a look in the thread. Gearbox swop..

I shortened down the rubber bellows and trapped it between the Elan 4 spd rubber bush after machining the 5 spd lever assy just north of the gearbox entry. I then made a sleeve to fit over the std bush onto which I welded a 4 speed lever set to length and angle. This I secured to the 4 spd Elan bush with 3 X M6 grub screws at 120 deg. I 'dimpled' the bush to help locate and secure the lever ass'y onto the rubber bush. I now have a 5 speed Elan which looks like a 4 speed elan. The only difference now is when I look for another gear I now find one. I also fitted a softer security spring in the gearbox. That made a big difference! The lever mod's and the redline MTL oil makes for a change very similar now to the 4 speed.

Best of luck with it..

Alex B .....

[CBUEB1771]

The Lotus box should be run on engine type oils. A 20 -50 or similar.

The Lotus Parts Bulletin that describes conversion of four speed Elans and +2 to the Lotus five speed box states that EP 80 lubricant is to be used. There is a series of parts bulletins related to the Lotus 5 speed box at the home page here under "Technical Tips". I suspect that Rohan is spot-on with his recommendation of Redline MTL.

[alexblack13]

what do you think the viscosity of Redline MTL is?

The lotus 5 speed box should NOT use 80/90 oils... Do so at your peril.

[vernon.taylor]

Salut

Merci for the feedback and advice.

Rohan - my rubber bellows bit is missing the retaining circlip - not sure how I'll fit one with the skirt-thingy higher up the lever. I guess cutting and bending/rebending a washer + a jubilee should do it.

Alex: Redline MTL is 70W80. Your link is bad but I found the thread and have started to work my way throught it - thanks.

@+

Vernon

[stugilmour]

Here is a link to the tech data for MTL. The same site has tech data for the redline motor oils as well.

http://www.redlineoil.com/product.aspx?pid=45&pcid=7

Not sure if this is relevant? Does it mean it indeed meets both requirements?

Satisfies the gear oil viscosity requirements of 70W, 75W, 80W, and motor oil viscosities of SAE 30, 10W30, and 5W30

FWIW, for a number of years I have used Redline MTL in my BMW M6 and the MT75 in the Plus 2 to good effect, although I take Alex' point that both of these gearboxes call up a variant of ATF or similar rather than GL-4 or similar or engine oil. One fantastic thing for the MTL is it's performance in very cold conditions (say -30 degrees and below), although I doubt this is an issue for our Lotus cars given their typical usage.

[alexblack13]

True Sir..

The problem is not the temp' though it's the flaming Salt they throw on the roads. Our classics hate it. So Loti sits on it's perch till springtime now.

The redline MTL is quite thin is it not. I will check out the numbers later. Rohan recommended it for the 5 speed some time ago and that's good enough for me. It sure works well. The change difference is amazing. Even if I say so myself though I do think I have got the lever right. It works very very well. AND it looks totally standard. I even kept the original knob..

Vernon.... It 'satisfies the requirements of 70 w 80'... Then again it also satisfies the requirements of the lower viscosity engine oils too. right down to 10 grade! It is certainly very 'thin' straight from the container ... Take your pick!

I can only repeat what the No 1 expert on Lotus 5 speed boxes has told me and many others, and that was do not use 80/90 oils. Run the box on a good 20/50. Remember the box WAS designed to be run on engine oils. That is a fact. I don't know anybody who put 70 / 80 oils into a Maxi.

Have fun anyway Vernon.. Have a good look at what I did with the gearstick.

Alex..