My '95 Defender leaks a few drops from the rear main oil seal (the original), the more it's used the less oil it drops. Otherwise it's oil tight.
My '56 Series 1 leaks a bit from the rear main oil seal (probably not the original), the rest of the engine is remarkably oil tight. I did replace a few leather seals, they need to be 'wet' to work and were past their prime.
I used to get into the same oil leak comments years ago relating to British bikes vs. Japanese bikes. I ran a BSA Thunderbolt, Triumph Trident and a Panther M100 outfit at the time. The only one that leaked a bit was the Panther because there's no seal at the back of the chaincase (just a lip in the casting to try to get the oil to run round the hole !). Oh and the Trident 'breathed' oil through the porous rocker box castings, but not a leak as such.....
If put together properly there shouldn't be a reason for oil leaks unless the design isn't that clever (ie. the Panther chaincase). I remember the BSA leaked gear ol from the gearchange shaft so I took it apart, machined an O-ring groove in the shaft fitted an O-ring and the leak was cured.
Maybe the reason for the leaks is that Land Rover/British bike is pulled apart more often to fix things and then relies on the person fixing it to seal everything up properly.......
Colin
