F - Gearbox
Another weakness on the Elite is the Lotus 5 speed box. It may have been good in an Elan, but for an Elite which is much heavier with a much more powerful and torquier engine, it just can't cope. And the gearchange has very narrow gate which is irritating. Lotus got it right with the S2 and its Getrag gearbox. If you are upgrading to a 2.2 engine then change the box. This box is bullet proof and a million times better in the Elite. The biggest problem is getting one because so few S2 cars were built. The box was widely used in other cars, mainly BMW's, but if you can get the Lotus version everything is there, i.e. ratios, bell housing, mounting plate, gearchange location. All of the above are customised for Lotus.
I pulled the box, clutch assy, flywheel and prop shaft from a wrecked Eclat 2.2 and paid £650, but it was worth it to get all of the parts I needed in one go.
One of the oddities of this unit is the lead weights. On mine there were two and Lotus used them to dampen vibrations. Lotus never solved the driveline vibration issue in the Elite. Witness the following efforts they used;
| S2.2 engine are mounted on "wings" cast onto the ladder frame to make the engine more stable. Look at an Esprit engine (like mine) and you will see where they are machined off! |
| The S2 gearbox has one, sometimes two lead weights attached to dampen it |
| Lotus tried three different configurations of prop shaft to solve the vibration problem |
| The S2 diff unit has a "X" frame welded across the frame top make it stiffer |
| The S2 diff is mounted on softer rubber bushes. These have holes drilled through the moulding |
| The S2 diff has different lower mounting studs to attached the transverse links |
| Later S1 and S2 cars have a link fitted across the ends of the lower diff studs to spread the sideways loads. This plus six respecifications of the lower studs themselves were required to prevent breakage of the stud. This part is safety critical - don't use anything but the proper part from Lotus - and don't think its smart to save £20 because you can find a cheaper part. It could prevent a nasty accident! |
So what about the lead (Pb)?
Well I can't believe Colin Chapman ever knew about this one! The gearlever mount is attached to a fabricated tin box bolted across the back of the rear gearbox housing. This arrangement is pure Lotus. The tin box is a complicated shape and it is full of lead! Moreover, my gearbox has another fabricated tin box bolted to the bottom of the gearbox rear housing and it too is full of lead. The lower one can be removed and on my car it makes no difference except for the weight saving. The top one could be replaced if you fabricated a new mounting plate for the gearlever; something I have not done.
All of these mods were done to tune out the vibrations and reduce NVH (noise, vibration & harshness). My car runs better without the lower lead weight because it is better tuned without it, perhaps because I have different engine mounts (no wings). Each car could be different. The answer to all of these NVH problems would be to fit a two-piece prop-shaft with a centre bearing. The Elite prop is really too long, but this design change was never done for cost reasons.
Fitting the S2 Getrag in a S1 Elite
It's not a direct swap, but its close. Here is what you need to know:
| The S2 chassis is different! A replacement galvanised chassis from
lotus is dual purpose and will fit either S1 or S2. There are three
differences
1) The upper rails of the chassis forming the front "Y" are chamfered on the underside to clear the gearbox 2) The first bulkhead may be slightly further back to clear the back of the gearbox. On my car I ground off the welds of the upper tin box and this was sufficient for clearance. You could fabricate a new upper gearlever mounting bracket. 3) the mounting plate which the gearbox sits on is completely different and requires a new bracket to be welded onto the lower edges of the chassis, both sides, so that the bracket can be bolted into place. |
| I had all of the above sorted by Spyder when the chassis was refurbished |
| The S2 requires a new speedo cable - very cheap from Cafco etc |
| You need the S2 propshaft because it is a different length and it has different splines. |
| The gearstick comes out in exactly the same place as the S1 car, but you don't remove it when installing/removing the box. You remove the top half of the gearstick, but that's all. |
| The gearbox is tight to install and it is done separately from the engine |
| The fuel line comes through the first bulkhead in the top right hand corner on the S1. For better clearance you should move it to the bottom right hand corner. |
| Use new gearbox mounting rubbers, old ones sag and collapse (actually they are a poor design for the weight of the box |
| The Getrag is much heavier than the Lotus; 10 - 15Kg depending on the lead! |
| You need to change the exhaust pipe for the S2 pattern so that it will clear the gearbox mounting bracket. On my car I bought a S2 downpipe and central silencer from Double S. The S2 Silencer is mounted differently (see Exhaust section) |
Oil - see also O - Lubrication section
There are huge arguments about which oil to use in these boxes. There are endless discussions on the web with respect to this gearbox (Getrag 265) as fitted to BMW's. Over time it will wear out the synchros, especially 2nd (doesn't every gearbox do this?). I have tried synthetic oils, but have gone back to the original Lotus recommendation of 20W/50. Be patient and let the gearbox warm up.