Rebuilding, uprating and fitting a Lotus 5-speed gearbox to the Lotus Elan.

Tips and hints to get a lasting solution.

By Victor Hollnagel Ba.Sc.Mech.Eng. and Danish club member

Many Lotus Elan owners seem Sierra fame, This might be the reason Prices to share the opinion that the Elan and even the for the reputation of the gearbox is in need of a 5th gear to keep Alfa Romeo gearbox used in the of being somewhat fragile. Elite Lotus 5 speed gearboxes revs and noise on acceptable type 105 Bertone Coupe In a 1558 ccm, 126 HP and are obtainable for realistic money, levels for motorway driving. (see the article written by Murray 1540 lb/700 kg Elan Sprint loads due to them being frequently The last 3 Elan Sprints deliv- Valentine in “Club Lotus News” are immensely reduced compared swapped for the later used Getrag ered from Lotus in 1973 was 3/1987, page 10). to the Elite. 5 speed gearbox for improved actually equipped with the 5- An important point was to avoid One of the above mentioned reliability. Only the mid gearbox speed gearbox from the slightly cutting neither in the chassis nor last 3 original 5 speed Elan section can be used from these bigger +2 version. Furthermore a in the interior in order to be able Sprints Elite versions, though. The Elan Lotus parts bulletin of 04.09.1974 to later convert the produced in needs to use a clutch housing was issued, describing a 5-speed car 1973 was with a Twin Cam engine flange conversion kit for the Elan actually and the short gearbox output Sprint and the section which has the gear lever Elan +2S 130. placed in a position as far forward Having and as close to the central gear- carried out the box housing as possible. Both the 5 speed clutch housing and the output conversion on my section are unique to the Elan own Lotus Elan version, and unfortunately Sprint DHC 1973, I will these parts are no in the following elaborate longer available on my experiences, from Lotus. There- hopefully inspiring other Elan fore quite stiff owners to consider a similar prices varying conversion. between £ 750 The Lotus 5 speed gearbox has and £ 1500 are got an undeserved reputation of asked for Elan +2 being troublesome. The number back to 5 speed gearboxes of Lotus Service Bulletins with its original depending on modifications could at first glance condition. This condition. Actually you are seem to confirm that image. appeared to be quite paying these prices only for the ambitious, as the chassis is nar- exported to Denmark and bought clutch housing and for the output Alternatives considered row around the gearbox, and as by Mr. Claus Gaarde; a long time section, because the central the gearlever comes up through Danish Lotus enthusiast. Claus gearbox section carrying the With that first impression in the floor in a for most cars un- could inform me, that he – after gears can – as mentioned earlier mind other alternatives were usual forward position. rebuilding the gearbox himself in – be used directly from the Elite considered, None of the above three gear- 1984 to the latest specifications – gearbox, which should be boxes could fulfil these require- drove 150 000 troublefree kilome- ments. Therefore the Lotus 5 tres with the box behind a slightly speed gearbox was further inves- uprated 140 HP Twin Cam en- tigated. gine. Claus kindly lent me all his technical information (parts list, Origin of internals service manual and service bulle- tins) on the box. Claus also had a Basically the gears in the Lotus nearly complete gearbox as spare 5 speed gearbox are from the BL parts, which I was invited to ex- Austin Maxi being one of the few amine. mainstream cars sporting a 5 After going through all this in- speed gearbox at that time. formation I could see no reason These gears were installed in a why a Lotus gearbox should not Lotus designed aluminium cast- be able to work satisfactory in my ing. Sprint as well. A new input and output section was designed by Lotus to convert Elite and Elan versions the original transversely mounted Maxi gearbox internals to its new The version of the gearbox used inline position. in the new Elite has a longer Output housings: At top output section and the clutch for Elan and below Elite Not fragile housing has a different engine possible to get for £ 100 to £ 250 flange compared to the version of depending on condition. The Lotus 5 speed gearbox was the 5 speed box used in the Elan When buying an Elan 5 speed originally intended for and used in and Elan +2. But the central gearbox remember to get the Top: Ford N/9 the quite heavy new Elite (2240 gearbox section carrying the propshaft with integral sliding Middle: Ford MT 75 lb/1016 kg) with its powerful 2 litre gears is the same on the Elite and spline at the gearbox end and the Bottom: Alfa Romeo 16 valve type 907 engine devel- Elan variants. gearbox mount too, as these oping 160 HP, all of which when parts are unique to the Elan such as Ford’s type N/9 gearbox, driven in anger took the stresses version as well. Ford’s MT75 gearbox, both of on the gearbox close to its limits. Lotus vs. Ford box Numbers and markings for a much stronger standard size ball bearing with a ring to com- The Elan is normally equipped In the bottom of the gearbox pensate for the slightly smaller with a Ford gearbox first used in housing a series number is outer diameter. This change the Ford Corsair 2000E. Hence stamped. greatly enhanced the rigidity and it’s often referred to as the Ford Some of the gearbox housings location of the input shaft, and the 2000E gearbox. This gearbox were machined to odd tolerances, lifetime of the input shaft bear- weighs 33 kg with its cast iron and were fitted with oversize ings. If your gearbox does not clutch- and gearbox housing. The bearings, which are no longer have this modification, you can Lotus box weighs only 27 kg with available. These boxes are identi- make it yourself, if you have Elan propshaft with inte- its aluminium housings. By fitting fied by “OS” stamped beside the Input shaft grated sliding spline the Lotus box you are ”adding series number. Try to avoid these lightness” to your car, just as boxes as they are more difficult to My own way to the Elan 5 Colin Chapman prescribed. rebuild. speed gearbox was to put an ad The gear ratios of the first 4 From series number 1492 and Top: New strong ball in Club Lotus News. For £ 1100 I gears are nearly the same in the on the angle of synchromesh on bearing + ring st nd ended up buying a dismantled Ford 2000E and in the Lotus box: 1 and 2 gear is changed from gearbox with a couple of new The biggest difference is found 5° to 6° to improve synchromesh gears and with the convenient st Bottom: Early narrow between the ratios of the 1 life and action. ball bearing possibility to inspect the box’s gears; the Lotus box’s 1st (1:3,20) From series number 2174 and internals too. My intention was to st is 7% lower the Ford box’s 1 on a nice trust needle roller bear- disassemble and renovate the st (1:2,97) giving a slightly easier ing for the 1 speed gear and an access to a lathe. To make room gearbox anyway. for the wider bearing you will However this appeared to have to spigot the input shaft be no cheap experience. But Vehicle speed slightly and deepen out the take it as a hobby, consider Final drive ratio: 3,778 pinion: 9 cr. wh.: 34 recess in the input housing. what other people spend on Tyre dynamic radius: 281 mm tyre dimension: 155/80R13 To improve lubrication of their hobbies (what did your the needle roller bearing wife spend on shoes lately?) st 1st 2nd 3rd 4th 5th Rev. between the 1 motion and and enjoy the originality of the rd Gearbox eng. rpm km/h the 3 motion shaft, two holes conversion which is done just st were introduced in the 1 like Lotus did. If done prop- Lotus 1000 9 14 20 28 35 8 motion shaft radially through erly, it should raise the value Ford 1000 9 14 20 28 - 8 the land beside the teeth of of your car too. Lotus 6500 57 91 133 182 229 53 the gearwheel. Ford 6500 61 91 130 182 - 55 If your input shaft does not Equipment st and less clutch stressing start accordingly revised 1 speed gear have these lubrication holes, you

from stand still with the Lotus box. is used. can drill them yourself. Grind off To carry out the conversion it is The other ratios are the same From series number 2016 and the hard surface with a small necessary to have good work- within 3%, a difference you will on a smaller roller bearing is used stone in a Dremel or equivalent, shop experience, to be patient, hardly notice. In top gear at 130 at the rear end of the counter- making a slight grub, buy a nor- and to use plenty of common km/h revs drops form 4600 rpm in shaft. In my opinion a slightly mal 3 mm brick-wall drill, grind its sense. the (Ford) direct 4th gear to 3700 retrograde step. side down to 2,5 mm, and you are th rpm in the (Lotus) 1:0,80 ratio 5 able to drill through the rather gear, giving a very useful 900 rpm Design changes hard steel using a little oil for drop and reduction in the noise cooling. Much cheaper than level on longer journeys. The Beside the above mentioned buying a new shaft with holes layout of the Lotus’ 5th gear as an changes an important change of 1st motion shaft puller overdrive is confirmed by the the odd narrow, large outer di- gearknob badge: ”1 – 2 – 3 – 4 – ameter ball bearing at the input 2,5 mm lubri- You should have access to a O/D”. shaft was made. It was changed cation holes hydraulic press and have com- mon workshop tools. It is

for £ 150. Remember to carefully grind off the sharp edges, not damaging the bearing surface inside the 1st motion shaft in the process.

rd 3 motion shaft support Bearings also necessary to be able to The gearbox contains 4 ball make up a couple of special parts bearings, 3 roller bearings and 5 and tools to get the job done needle roller bearings. They are properly. You should get hold of all of RHP or Torrington origin. the original section F from the Only 2 ball bearings and 4 nee- Elan +2 workshop manual and all dle roller bearings are standard the Lotus service bulletins regard- catalogue items, the other 6 ing the 5 speed transmission. It bearings are special. will be of great help to you, if you The way to get hold of all the have a parts list, too. bearings is to contact a bearing On that basis you should be specialist company with the right able to make a well functioning 5 UK contacts. Provide the list of speed gearbox and even enjoying the bearings, and they should be the pleasure of doing the job able to source them all for you. yourself. The 6 special bearings will not be cheap. Be prepared to pay in the region of £ 500 for all of the 12 bearings. Modifications up through the tunnel in a rear- Gearbox mounting plate ward position in relation to the cut Selector shaft finger out in the tunnel and the tunnel According to Lotus fitting in- console. This is compensated for struction the gearbox mounting The standard selector shaft fin- by making up a new gearstick plate for the Lotus box should be ger has round sides, which grip with an offset rubber bush house, mounted to the chassis in holes into the selector fork’s square cut- with the gearlever welded to the drilled in new positions. I pre- outs with straight sides. The 3rd/4th front of the bush housing. The ferred to make up a new gearbox selector fork is made of brass and original gearstick is disassembled has narrowed down sides. Con- at the concentric rubber damper, sequently the sides of the selector modified fork cut-out are deformed leading to move the bracket with the to a sloppy gear change. 5th/rev. lever until its cut out was The solution is to make up a aligned with the selector fork cut selector finger with a square head outs. and straight sides just like the selector fork cut out, which it grips Support ring original The input shaft and the 1st mo- tion shaft are mated with splines around the above mentioned heavier ball bearing and a roller bearing. The inner ring of the improved ball bearing only sits on Gearbox mounting plate into. Make the revised finger from the spigotted end of the input mounting plate which made it a piece of Uddeholm “Arne” steel, shaft. The alignment of the mated possible to use the existing holes which can be hardened and shafts to the ball bearing and the in the chassis instead. tempered to the right strength and support of the inner ring of the hardness. The selector shaft is Concentric slave cylinder modified to take the now Allen the lower gearstick part is care- fully straightened, a M10x1 thread screw secured selector finger. The clutch originally uses an is cut at the end of it, the conical outside mounted slave cylinder, Lever pivot too close to the exhaust manifold.

th On hot days and in town traffic The lever for the 5 gear and this situation often leads to original the reverse gear is secured at its cooked clutch fluid and a mal- pivot point with a tiny circlip which functioning clutch release. is reported to easily slip off. The Support ring modified solution is to make up a new pivot point and securing system of a

ball bearing can be enhanced by making up a support ring filling up the remaining space between the turned down M10 bolt of 8.8 steel 1st motion shaft spline and the quality. This bolt is secured by a To overcome this a SAAB 900 inner diameter of the ball bearing. M6 Allen screw. By tuning the concentric slave cylinder was rubber spring is cut down, suit- tolerances it is now possible to mounted inside the clutch hous- Spacer able spacers made up, and the have a secure and free turning ing, doing away with a lot of the new forward offset gearlever pivot without sloppiness. mechanical parts. A console plate Put a 1mm plain washer over

Selector line up the selector link pin (position 4) to space the selector link out from The cut outs in the selector the gearbox side. This will take up forks and in the 5th/rev. lever should be aligned in neutral; 1 mm spacer here otherwise the gear lever cannot be moved across the gaiter freely. In my case the cut out in the

was made up to take up the new clutch cylinder. The necessary hydraulic lines, fittings and an excess sideways sloppiness in outside bleed screw had to be the gear lever when it is in the made up too. 1st/2nd gear position.

Offset gear lever can be assembled. The rubber 5th/rev. lever was about 0,7 mm An offset gearlever should be bushing used is a part from the out of line. This was compensated made up like the lever used on rear suspension A-arm outer by making up new retainers (see the original 2000E 4 speed gear- bushing. The mounting of the new drawing position 18) for the inter- box, but the offset should be to - disassembled - gearlever to the lock plate with 0,5 mm eccentric the front instead to the rear. The gearbox is now much easier too. holes and threads. It was now reason for this is that the gear The photo should give the general possible by turning the retainers lever from the Lotus box comes idea.

Assembly teethes and the shafts. Instead Be sure to use a magnetic bot- fied tolerances. They are of great take a surplus synchroniser collar tom drain plug to catch steel importance to the function and It is wise to make a trial assem- ring and have it bolted up in a tool deposits from the oil. I ended up shift quality of the gearbox. bly of the gearbox with the old with a lever arm. This tool can be using one from a Triumph Spitfire Use the best synthetic gear oil bearings to check the function used to carefully hold back the 2nd gearbox as it was NLA from you can get, for instance Castrol and free running of all the parts. motion shaft on the 5th gear syn- Lotus. TAF-X. The gearbox will take 1,7 Shift through all gears and turn chroniser mechanism while tight- You will need an approx. 15 cm litre. the shafts. For my part on my trial ening down the nuts, without longer speedometer cable. A You should now be able to en- assembly I found the input shaft overloading the gearbox. cable specialist firm should have joy motoring in your Elan even binding and loosing up for every The baulk rings can present a the answer to that. more when cruising long dis- 180° turned which was tracked slight problem, as they have to be Otherwise do exactly as stated tances in 5th gear! down to an out of true 1st motion of the correct angle, which as in the Lotus workshop manual, shaft. I had to have a new shaft mentioned earlier was changed. It and be careful to keep the speci- fitted! should be possible to feel if the When fitting bearings to the baulk ring fits properly to the cone gearbox housing, always heat up of the corresponding gear wheel. I the housing with a heat gun. had to go through a couple of sets When heated, aluminium expands before I had a full set of the cor- three times as much as steel. rect angle baulk rings. This should assure you correct To eliminate the risk of the and much easier fitting of the bearings rotating in the gearbox bearings. housing when the gearbox The gearbox housing should be reaches working temperature, or thoroughly cleaned before as- due to bad tolerances, always use sembly. Nowadays ball and roller Locktite bearing securing fluid. Be bearings are dimensioned not careful not to drop Locktite into only by the loads, but by the the bearings. cleanliness of the lubricant as All bolts and nuts should be well. Even the smallest amount of secured with Locktite for bolts, dirt can greatly reduce the life- especially the long Allen bolt span of your expensive bearings. securing the input shaft to the 1st It pays well off to be thorough. motion shaft. It is critical if it works When tightening the big nuts at loose. But it won’t if you are the 3rd motion shaft and on the 2nd careful.

motion shaft, the workshop man- Generally, Locktite only works ual says that you should put the when the surfaces are clean and gearbox in 1st and 3rd gear at the free from oil and grease. same time, locking up the gear- The sealing compound to use box. I would advise you not to use on the gaskets is Hylomar or an this method, because you put equivalent not drying up RR immense loads on the gear specification sealing compound. a brand new 5th gear pinion speed gearbox in an Elan (you sourced all bearings and welded Acknowledgements among numerous other important will have to cut a little in the chas- the balancing weights properly This project could not be tack- bits and pieces. sis and move the engine and onto the propshaft. led without invaluable help from Alan Voight supplied many NLA gearbox a bit forward. It has been Torben Valerius provided the many friends and specialists: items. done a couple of times with good possibility to have some gearbox Nick Abbott at the Bull and Michael Taylor sold me a nice results and it’s not expensive). surfaces cleaned up in a big lathe Butcher in Turville sold me the used Elite gearbox, a new input Claus Gaarde supplied his at his disposal. gearbox, provided a nice meal, a housing, not to mention finding a complete Lotus literature on the Frank Thrusholm - last but not pint of Breakspears bitter and bed gearknob with the all important subject and the opportunity to least - took the trouble to read the and breakfast on my visit to col- “1-2-3-4-O/D” shift pattern badge have a thorough look at the hard- proofs on my ramblings. lect the box in England. to enjoy. ware. Pat Thomas at Kelvendon Murray Valentine, Australia Peter Kjul, Niels Johansson and Thanks to you all! sourced a much needed new 1st kindly sent me his absolutely Henrik Andersen provided knowl- motion shaft. thorough an detailed 10 page edge of material and heat treat- Paul Matty Sportscars sourced description of how to fit an Alfa 5 ment for the selector shaft finger,

Lotus 5 speed gearbox bearings

Outer Pos. # Inner di- Outer Width of. Qty. Bearing Make Type Width diameter of drawing ameter diameter flange flange

4 1 Ballbearing RHP 6207 35 mm 72 mm 17 mm - -

5 1 Rollerbearing with flange RHP 17LRJ30 30 mm 72 mm 16 mm 4 mm 3”

8 1 Needlebearing, caged ? ? 20 mm 26 mm 12 mm - -

14 3 Needlebearing, caged Torrington FWJ 354025 35 mm 40 mm ≈ 24,5 mm - -

14 1 Needlebearing and Torrington TE-160-680 27,15 mm 40 mm 35,3 mm 3,9 mm 55,55 mm aksialneedlebearing with innerbushing

1 1 23 1 Ballbearing with recess RHP 2LJ1 /16 1 /16” 68,7 / 12,6 mm 8,5 mm - in outerring 59,5 mm

1 1 24 1 Rollerbearing RHP 14RJ1 /16 1 /16” 68,8 mm 16 / 12 mm - - with different with of (innerring / inner- and outer ring outerring)

31 1 Ballbearing RHP 6006 30 mm 55 mm 13 mm - -

41 1 Rollerbearing RHP 1DXXLLRJB30 ≈ 30 mm 55 mm 25 mm - -

45 1 Ballbearing, RHP 3LDJT20 20 mm 47 mm 20,5 mm 4 mm 52 mm double with flange

Engine rpm

Final drive ratio: 3,778 pinion: 9 cr. wh.: 34 Tyre dynamic radius: 281 mm tyre dimension: 155/80R13

1st 2nd 3rd 4th 5th Rev. Gearbox km/h eng. rpm Lotus 130 - 9292 6360 4636 3687 - Ford 130 - 9316 6475 4636 - -

Lotus Elan 5 speed gearbox shafts, bearings and gearwheels