Fast Marina Magazine

The worst gearbox. The A Series engine has to be the most reliable engine built in the last 50 years. After all it won the Monte Calo Rally...but the gearbox is absolute rubbish. 1st and reverse especially. You would have thought that they would have designed something better :?

Got to agree about the gearbox. The Marina single rail gearbox was originally based on the 948 Herald three rail gearbox from the early 60s. Some of the bearings etc are interchangeable, by the time you put Marina TC and Dolly 1850 power and torque through it, it won't last long. That why the Dolly Sprint needed a different gearbox - and before someone asks, no they aren't interchangeable.

A series is an excellent lump gearbox as Chris says but at least the Triumph boys keep parts alive.
but
Its possible to fit a 1.8 input shaft into a Dolly sprint box so it should be possible to fit a 1.3 shaft into the Dolly sprint. Trouble is Sprint boxes are getting really rare.

jiversteve wrote:Its possible to fit a 1.8 input shaft into a Dolly sprint box so it should be possible to fit a 1.3 shaft into the Dolly sprint. Trouble is Sprint boxes are getting really rare.

Wasn't the Dolly Sprint box (and diff) from the "big" six saloons and TR sports cars?

iirc the GT6 got the single rail gearbox first (with very close ratio gears, 2.65/1.78/1.25/1.00 :shock: ), with beefed up internals to handle the 115lb/ft of torque.

Does that make this the gearbox fitted to the widest range of engines (in either 3-rail and single-rail form)?

Triumph 948, 1300 and 1500 OHV four (Herald, Spitfire)
Triumph 1850/2000 OHC (Dolomite/TR7)
Triumph 2000 OHV 6 (GT6)
A-series (Marina)
B-series (Marina)
E-series OHC (Aust Marina)
O-series OHC (Marina)

5055 wrote:The worst gearbox. The A Series engine has to be the most reliable engine built in the last 50 years. After all it won the Monte Calo Rally...but the gearbox is absolute rubbish. 1st and reverse especially. You would have thought that they would have designed something better :?

Was the Morris/MG gearbox from the Minor and Midget any better? Check out the Midget gearbox here. Ratios Sprite 3.627/2.374/1.412/1.000 and Midget 1275 3.200/1.916/1.357/1.000

I've got the 1850HL overdrive 'box in my GT and that bolts straight to the bellhousing, cut 1/2" off the input shaft and it all goes together. The g/box and o/d is 1/2" longer than the Marina unit so I moved the engine forward and had to cut a hole for the interlock box in the trans tunnel. Also a bespoke gearbox mount. Speedo drive goes straight on, no mods required.