Fitting a Ford Type 9 Gearbox to a Scimitar GTE with Essex engine

Transcription

1 Fitting a Ford Type 9 Gearbox to a Scimitar GTE with Essex engine The following missive doesn t contain detailed instructions on how to fit a type 9 gearbox to every variant of Scimitar or Sabre, but tries to bring together lots of relevant information, some of which is contradictory within different sources! The type 9 was (it appears) developed from a 4 speed. Conventional 4 sp gearboxes accept drive from the engine via the 1st motion (input) shaft. In the intermediate gears (1,2,3) a pinion on the end of the 1st motion shaft drives the laygear which in turn drives, via the selected gear pair, the 3rd motion (output) shaft to which the propshaft is connected. In top (4th) gear it's different. Drive from the engine still arrives via the 1st motion shaft and its pinion still spins the laygear. But in 4th gear the 1st and 3rd motion shafts are locked together so the laygear does nothing other than spin. Because of this conventional gearboxes are designed with laygear bearings that are adequate for the limited time spent in intermediate gears. Most of the time the gearbox will be in top (4th). In the case of the earlier type 9 (and many others) the laygear bearings are uncaged needle rollers. When a 5th gear was added to the basic 4sp design it was necessary first to extend the laygear to enable another pinion to be added to it and then to fit a corresponding pinion / synchro assembly to the 3rd motion (output) shaft. Ford made room for all this by adding an extra casing sandwiched between the gearbox main casing and the tailhousing. In the course of redesigning the laygear with a 5th gear pinion a large and robust bearing replaced the rear laygear needle roller. The front laygear needle roller bearing was however retained. The problem was that the gearbox spent most of its time in 5th and drive in this gear reverted to the intermediate pattern (1st motion shaft to laygear to output shaft) and the front laygear bearing couldn't cope with a task for which it wasn't designed. High mileage users (reps!) experienced gearbox failure before 20K miles and the type 9 gained a reputation for unreliability. So Ford modified the laygear to take a decent front laygear bearing. This mod can be seen once the bellhousing is removed because the bearing support (a top-hat shaped spigot) is bolted to the front face of the gearbox in line with the laygear. I believe that

2 later type 9s identified by having aluminium bellhousings were further modified to improve (or cheapen!) the method of supporting the front laygear bearing but I haven't seen one in the flesh (or aluminium). Source Tony Idle. To fit the type 9 to the Essex in a Scimitar or Sabre, there are seven main things to consider: 1. Bearings. There are early and late 4 cylinder and V6 boxes (modified laygear bearing) and to modify an early box to accept the later bearing requires lots of machining. Early boxes will not last long behind an Essex. 2. Input shaft. There are long and short input shafts and input shaft covers. The short (6.9 ) input shaft for the 4 cylinder engines has 18 teeth with a short cover. The long (8.1 ) input shaft for the V6 engines with a long input cover has 18 teeth for the 2.3 or 19 for the 2.8/2.9. The diesel gearbox has a long (8.1 ) shaft with 18 teeth (as the 2.3 V6) but a short cover. There is also a special transit length shaft used by Caterham with the K series I suspect that this must also be in the mk2 Sabre?

3 3. Ratios. 1.6, 1.8, 2.0, 2.3 V6 1st nd rd th 1 5th inc 4x4 1st nd rd th 1 5th 0.83 diesel 1st nd rd th 1 5th Speedo drive.

4 5. Bellhousing. 1. Ford didn t fit the type 9 to the Essex, so the only easily available off the shelf option currently, is the Burton alloy bellhousing ( 2. There is a rare Ford option the Ford Consul or Mk1 Granada with the 2.5 litre V6 Essex or 2 litre V4 Essex, used the type E four speed gearbox which the type 9 (also called the type N) box was based on. Apparently the bellhousing part number is: 72GB 7505 LA 3. Another option is to make an adaptor plate to allow the type 9 gearbox to mate to the Essex bellhousing. This allows you to retain the original hydraulic clutch (if fitted). Details here: 4. Finally, cutting the front flange from the type 9 bellhousing and welding a plate of steel in it s place, suitably cut to mate with the Essex, has been seen. Note for options 3 and 4 above, there are two different type 9 bellhousings; 6. Clutch. The type 9 is a cable actuated clutch as standard, therefore a 4 speed Scimitar will not need modification. To convert an overdrive car to cable, the simplest option is to locate a cable pedal box. Failing this, the pedal and bulkhead will need modifying. To convert the gearbox to hydraulic, the bellhousing can be modified to mount the slave cylinder, or a concentric clutch can be fitted.

5 7. Gearstick position The gearstick will be too far rearward, there are three options: 1. Bend the original stick remove and apply localised heat if necessary. 2. Use/manufacture a gearstick from a small sports (SS1/SST/Sabre) which is cranked. 3. Shorten the gearbox tail housing. This requires alloy welding - details here: Other considerations. 1. The propshaft will need modifying for length and front sliding flange. 2. The gearbox crossmember may need modifying although the rubber mountings are identical. Type 9 History. The five-speed Ford Type 9 gearbox was the first 5 speed transmission fitted to production Ford RWD vehicles. It survives to this day as the stalwart for kit cars and club racers. The T-9 is arguably the most prolific and longest serving mass produced transmission. As an indication there were more than 2.75 million Sierras produced globally. (Not all had the Type 9). Origins. To better understand the rational for the Type 9 we need to take a look at its predecessor, the Type E, 4 speed. Despite this robust Top-loading unit having a Cast Iron housing, with the gearset being assembled through an aperture on the top of the casing, it only weighed in at 22kg (Excluding the bellhousing). Fitted to 2-litre Cortinas, Granadas, Escorts and the Mexico, this four-speed unit was capable of transferring up to 180bhp without serious modification. It featured a separate bellhousing, aluminium remote tailshaft housing, quick-shift gear lever and evenly spaced ratios. In its day it was well suited to the volume production vehicles it was fitted to. Being the standard transmission of the day, floorpan layout developed around this unit, and would be a serious influence in the design of the next generation gearbox. Ford, being a serious motorsport competitor, has always been involved in production saloon car racing and the 70s and 80s were no exception. In a quest to match the transmission to highly tuned engines with narrow power-bands Ford partnered with specialists such as Quaife and Hewland to produce various gearsets with customised ratios. Close ratio 4 speed, and even 5 speed clusters that would fit within the casing.

6 Experience gained through competition had proven the reliability and performance of a 5 speed gearbox built around the constraints of the 4 speed casing. Performance alone was not reason enough to introduce a production 5 speed into Ford s vehicle line-up. Fortunately improved performance was only part of the package, as benefits in comfort and Noise, Vibration Harshness (NVH), would also be achieved. And so the decision was taken to bring a compact, versatile 5 speed transmission into production. Rather than develop a completely new design the Company chose to adapt the old (but good) Type E gearbox. By physically grafting the fifth gear onto the back and using a shorter extension housing, it was also possible to fit the box into older designs such as Granada and Capri. The fitment of the additional gearset only increased the mass of the gearbox to 33kg, without the bellhousing. Testimony to a well thought out design. Successors. Having successfully introduced the Type 9 5 speed transmission into production the limitations of the evolution of this transmission meant the end of the road was inevitable. This came in the form of 2 successors: One, a home-grown Ford product, and the other from Gear Specialists Borg Warner. Both were slicker in selecting gear as well as having a higher torque rating to cope with the increase in power of the newer generation 4 valve and Turbo charged engines. The Ford 'MT75' which eventually replaced the Type 9 gearbox altogether was first fitted to the higher output vehicles: Sierra 2-litre Twin Cam, Sapphire Cosworth 4x4, Granada 2 litre Twin Cam, 2.9 V6 and Diesel. This fitment was made at the end of 1988, and was eventually applied across the range. Production. With the introduction of the Ford Sierra for Model Year 1983 (Which started production in August 1982) Ford took the plunge and introduced the Type 9. At this point it s important to remember that the T9 was initially offered as an option on certain variants; not standard fitment across the range. It may be of interest to note that it was common practice to fit a common transmission across all passenger/ light commercial applications therefore the inclusion of the Transit and P100 (A hybrid light pick-up developed in South Africa around the Cortina and later carried over to the Sierra. The Type 9 was offered on the following models/ variants: Sierra 1.6/1.8/2.0/2.3 Sierra XR4i Sierra XR4x4 2.8 Capri 1.6/2.0 Capri 2.8 Granada 2.0/ 2.3/2.5d

7 Granada 2.8/ 2.8i Merkur XR4Ti. (American market Scorpio 4 X 4 Transit(LCV) P100 (LCV) Ford owners could now enjoy the driving experience previously reserved for owners of more expensive luxury vehicles. The lowering of engine speed for a given road speed made open road driving a more relaxed affair, while (under most conditions) reducing fuel consumption, and even wear and tear on the mechanicals. By way of example: The Ford Capri 2.8 injection with a 4 speed gearbox, fitted with a 4th gear ratio of 1: 1 and a final drive ratio of 3.09, had the engine turning at 3409 RPM at 120km/h (70 MPH); whereas a vehicle fitted with the 5 speed unit with a 5th gear ratio of 1: and the same final drive ratio of 3.09 had the engine turning at 2899 RPM at the same speed. This 15% drop in engine revs did not go unnoticed, with the car receiving rave reviews from car testers and the public. All forward gears were fitted with synchromesh. Visible differences between variants. When confronted with the proposition of identifying the differences between variants of the type 9 transmissions, the layman would be somewhat perplexed, as outwardly they appear very similar. Here s an overview of easily identifiable differences: Note: All original Ford input shafts have the traditional 1, 23teeth input shaft spline configuration fitted to Cortina/Capri & Sierra etc.

8 Other differences between early and later Type 9 gearboxes: The early unit had a single rib running lengthways along the extension/ tailhousing as well as an internal bush. The parts making up this assembly are not interchangeable, as follows: The earlier selector shaft with shorter operating pin has to be used with the early housing. Obviously for each final drive/ transmission application there will be different speedometer pinion and gear variants. Common problems. Although the T9 could cope with the torque requirements of engines producing up to approximately 200 HP, they did experience problems in the following areas: In V6 application early wear of the layshaft bearing was not uncommon. Poor layshaft alignment and marginal bearings led to a high failure rate on early models. Ford finally resolved the problem in 1986 when a better located, up rated bearing was introduced. Unfortunately this is not rearward compatible, with major machining and replacement of gear clusters being necessary Gear engagement was often difficult and notchy especially when cold. The layout of the linkage (As a result of the packaging to fit the unit to existing tunnels) was probably the root cause of the problem, but by using synthetic and semi-synthetic lubricants

9 improvements could be achieved. Ford recommend 75W 90 semi-synthetic (Ford Part No A83SX 2 c 175-AA) with the following fill volumes: 2wd 1.9 litres - 4wd 1.25 litres plus ½ There was an inherent design fault in the Type 9 gearbox. The dowel locating the bellhousing to the gearbox is split, and the locating hole in the gearbox casing is not blind. As a result, in the original application, water runs through the vents behind the bonnet, and settles in the groove between the bellhousing and the gearbox. Over time, this can (and does) eat through the gasket, and eventually runs straight into the gearbox. A simple cure is to run a bead of silicone sealant across the joint. Even if the gasket fails, the silicone will seal the hole, instead of running into the gearbox. There is also no drain plug on these gearboxes, as they are supposed to be "lubricated for life". The only way to drain the box is to raise the front of the car, remove the propshaft, and collect the oil that runs out. The solution here is to drill and tap a plug into the casing. (The difficulty in changing oil was probably also a contributory factor to the layshaft bearing failures). 6 speed Caterham gearbox. Caterham developed a 6 speed gearbox which was a direct replacement for the type 9. Suitable only for track use, it featured the following close ratios: 1st: 2.69:1 2nd: 2.01:1 3rd: 1.59:1 4th: 1.32:1 5th: 1.13:1 6th 1.00:1

10 6 speed Quaife gearbox. Quaife also offer a 6 speed replacement sequential gearshift with or without overdrive top. The new Quaife 6-speed heavy duty in-line RWD sequential gearbox has been designed as a direct replacement for the Ford Sierra Type 9 gearbox, and incorporates a modular gear cluster on 80mm shaft centres. Quaife has returned to its first principles with this new heavy duty in-line gearbox, opting for a cutting edge, clean-sheet design. The result is a new 6-speed sequential unit, the QBE60G, which weighs in at just 38 kilograms. Designed for rear wheel drive applications capable of handling up to a maximum of 300 lbft and 375 bhp, the QBE60G offers ultra-rapid and smooth gearshifts, allied to superior strength and reliability, and even features paddle shift compatibility.

11 The Quaife 6 speed heavy duty in-line RWD sequential gearbox has been designed with open face dogs on both the gears and drive discs to allow for easier gear interchangeability. The Quaife 6-speed heavy duty in-line RWD sequential gearbox has a drum type sequential gearchange system which produces a positive engagement with the gear lever position options. The QBE60G has a front face which is designed to mate directly to an existing Ford Type 9 bellhousing, using the original four or optional six bolt fitment and acts as a direct drop-in replacement for the original Ford Sierra Type 9 gearbox used in Caterhams, Escorts, Ginettas and Westfields, as well as a wide variety of specialist cars. QBE60G customers can specify long and short input shaft options QBE60G according to customer preference and three ratios sets are available, in either straight cut or helical tooth forms. 1st 2nd 3rd 4th 5th 6th Spur Spur Spur Spur st 2nd 3rd 4th 5th 6th Helical Helical Sources: