"Get Rag that Tiger!"
An Article by Derek White
Preface: Derek White has been working on his Tiger for over a year now, with this Getrag 265 transmission installation his latest project. The Getrag is a very nice transmission made for many cars in Europe, of which the BMW is imported into the US. Being in South Africa, Derek faces many unique problems with parts, available local knowledge, and auto speed shops and mechanics.
He has posted the question, below, along with a picture of his status on the Tiger List. Unfortunately, the List will not accept attachments. We have, therefore, reproduced the text and graphic below. We look on this as a first installment on an article from him on this project, along with even more descriptive pictures and data. (Are You Listening, Derek? (8-)
Putting a Getrag 265 gearbox into a Tiger
I found my Tiger under a mango tree and bought it for $120 without engine or gearbox. An old 302 was easy to find, even in Zambia, but a 4-speed toploader was a problem. When I spoke to Alf Dragan in South Africa, he told me that all the Cobra and Tiger racers in South Africa were using a very strong Getrag gearbox that was found in big BMW's in the early 80's and in some Opels. After more investigation I found that this was the Getrag 265 gearbox and it was also used in the Jaguar XJS V12, some Maseratis but mostly in big BMW's. Vicarage Jaguar uses one in their racing E-type and Metric Mechanic makes special versions for racing BMWs (http://www.metricmechanic.com.)
These gearboxes are very easy to find and very cheap since they always outlive their host cars. In a web search of the USA I found thousands of them for under $100. Look for them in 6 cyl BMWs: M3 and big six '80 to '82, 528e '82, 535, 635, 745 in '85. They have removable bell housings which is why they are easy to adapt. They might have casting numbers starting 262, but you can tell it is a 265 if it has a 97mm long center casing which is sand cast so it looks a bit duller than the front and back castings. They can take 350 ft/lbs of torque in standard form or 400 ft/lbs with the Metric Mechanic upgrades.
You can get new aluminium bell housings made to fit these gearboxes onto a SBF or SBC for $200 in South Africa. I only found this out after I had TIG welded the back of the Getrag bellhousing onto a Ford aluminium bellhousing.
The ratios of the 265 are well suited to the tiger at: 3.82, 2.20, 1.39, 1.00, 0.81
I am using the less common Opel 3.0 litre 265 gearbox as it has a splined output shaft. The BMW boxes have a flanged output so require a propshaft with a sliding section.
I recently fitted my prototype bellhousing plus 265 Getrag to my 302 block so I can tell you these distances. These are for the Opel box and may be a little different for the BMW or Jaguar versions:
- Block to shift lever 645mm (and 675mm block to output shaft
- Engine mount stud to shift lever 965mm
- Block to side gearbox mounts 390mm (on the side, 1/4 way up)
- Block to rear-bottom gearbox mount 550mm
(there are two different mounting positions, probably to match different cars.)
The shift lever comes up in the center of the transmission tunnel, about 3 inches in front of the cross member. I removed a thick rubber spacer from the shifter mount in order to get the shifter further forward. You do have to cut a new hole for the shifter but it is in a very nice position. Other useful info is that the 265's have either a Ford or a Chevy input clutch spline (so I am using an out of the box Centerforce clutch disk and pressure plate.)
I made up a simple bracket that bolts to the chassis and holds the rear engine/gearbox mount. It uses the rear-bottom gearbox mount. My small 3/4 inch Nissan slave cylinder bolts onto two heavy aluminium lugs that I welded onto the bellhousing. I will adjust the pedal pressure by changing the length of the fork or if I have to I'll sleeve the master cylinder. The fork is a slightly modified fork from the donor Opel. My propshaft is a Landrover rear propshaft with the front U-joint and splined section from the donor Opel.
I haven't driven the car yet and probably won't for a while since I've moved myself to Sri Lanka and the tiger to a restorer friend in Zimbabwe. Once I do drive the car, I will talk to a BMW agent or Metric Mechanic about an appropriate speedo drive gear for the gearbox or I may just put a small reduction box at the speedometer.
I would love to hear from anyone else who tries this. My car is in pieces so if you want any of the fabricated pieces copied let me know. From what I have read and heard, this is a stronger gearbox than the T5 and it has ratios that are better suited to the Tiger. It also puts the gear stick in a better position without having to cut the cross member or find the rare AMC tail housing. Another big bonus is the cost. If you buy the bell housing for $200 and the gearbox for $50 (they are out there, I kid you not!) you can have a strong overdrive five-speed transmission for around $300 and a bit of work.
I might put together a few kits if there is enough demand. I will definitely look into supplying these bell housings to the Ford/Chevy community in the USA as I feel it could be a real money-spinner. I will attach the only picture I have of the setup for those of you who'd like to try it. It will be removed by the list server but Steve can put the picture with this description onto http://www.TigersUnited.com. (DONE!)
Good luck and keep me posted if you try this in your tiger.