Borg Warner T5
Several of our bellhousings connect to the Borg Warner T5 including the Pinto Or Cosworth To Borg Warner T5 Bellhousing, the Vauxhall 2.0XE Engine To Borg Warner T5 Bellhousing (also connects to the Saab B204 and B234) and the VW / Audi 1.8 Litre To Borg Warner T5 Bellhousing. In addition we manufacture the Borg Warner T5 Hydraulic Release Bearing Kit which is attached to the nose of the Borg Warner T5 gearbox. Please note the design for the Borg Warner T5 was sold to Tremec and all T5-based gearboxes are now badged as Tremec TR-2450.
Gearbox Hole Pattern
All of our conversions are prototyped using the Borg Warner T5 gearbox as fitted to the Ford Sierra Cosworth 2WD, which was introduced in 1986. However this variant of the gearbox was one of only many Borg Warner variants as explained on the Borg Warner T5 Wikipedia page. We have sold many of our bellhousings to customers in the USA, who have sourced mainly Mustang T5s, all of which connected successfully to our bellhousings with some provisos. The diagramme below shows that 2 bolt patterns were employed. Pattern A – tall, narrow, odd ear left looking forward – is the pattern that we use for our bellhousings. If you have a Pattern B T5 – most General Motors including Camaro and Firebird but not including some Commodores – then our bellhousings will not fit your gearbox. Please see this article by Stan Peace of Pro-Performance for an in-depth account of how to identify your T5 gearbox even without an ID tag.
Input Shaft Splines, Diameter
The other main difference between USA and UK sourced T5s relates to the input shaft diameter, length and number of splines. The Sierra Cosworth T5 used a 1″ (25.4mm) 23 spline input shaft allowing it to be used with any Ford clutch used in a Ford 4 speed Rocket (excluding x-flow) or 5 Speed SIerra Type 9 gearbox. Standard and competition clutch friction discs are readily available in the UK. The most common donor gearbox – the Mustang V8 – has the same input shaft length (from gearbox front face) of 7 1/8″ (180mm) with a 1 1/6″ 10 spline input shaft. With this gearbox you will need to obtain a friction disc of between 8 1/2″ and 9″ (215 – 228mm) depending on application that has the 1/6″ 10 spline centre. We are in the process of having a special disc manufactured for us.
Cable or Hydraulic Actuation?
If you are intending to employ cable clutch actuation using our RS2000 Clutch Release Bearing and RS2000 Clutch Release Fork. You will need to bear in mind that the input shaft collar / bearing retainer plate / thrust bearing tube on the Mustang V8 has an external diameter of 1.43″ (36.3mm) whilst our RS2000 Clutch Release Bearing has an inside diameter of 1.36″ (34.5mm). Other USA-sourced bearing retainers, such as those from a Chevrolet S10 have an external diameter of 1.37″. You will need to either a) have the bearing retainer turned down; b) have a new smaller diameter tube welded onto the bearing retainer plate c) source a bearing with a larger internal diameter. Our bellhousing is manufactured with a gearbox centre hole of 123.2mm diameter. The Ford T5 bearing retainer has a diameter 124.7mm however the TVR retainers have a diameter 118.9mm. In the case of the TVR a 2 mm thick ring will need to be made so that the bellhousing is located concentrically.
An easier solution to the actuation is to employ a hydraulic system using our Borg Warner T5 Hydraulic Release Bearing Kit and Plumbing Kit For Type 9 Or T5 Hydraulic Release Bearing. This kits fits over the nose of the T5 gearbox, being fastened over and through the bearing retainer using longer mounting bolts. Since the bearing retainer tube is no longer needed (the bearing slides within the hydraulic cylinder) the thrust tube can be cut down to just above the oil seal as described here. Note that our VW / Audi 1.8 Litre To Borg Warner T5 Bellhousing utilises a release bearing that attaches to the inside of the gearbox.
Spigot or Pilot Bush
From the chart below you will see that the majority of the T5s use a spigot bearing or pilot bush with an internal diameter of 19/32″, which is 0.59375″ or 15.08mm. Happily this means that our standard spigot bearing with an internal spigot diameter of 15mm (0.59″) and external spigot diameter of 21mm (0.83″) will fit the Ford, VW / Audi and Vauxhall engines and most USA T5s (please check your UK T5, as despite what the cart below says our experience is that they use the same standard 15mm input shaft pilot hole diameter). Length of the spigot bearing is 16mm (0.63″).