O - Lubrication & Maintenance
Engine Oil: Lotus engines tend to consume oil a bit and in my experience the 912 engine runs fine on Castrol Magnatec, but I use the type for "standard" cars as it is closer to the 20/50 type of oil the engines were designed for. Certainly helps the oil consumption
Filter: The filter must have a non-return valve, which of course the ridiculously expensive Lotus item does. Many other makes do have this, but you need to be absolutely certain otherwise the engine will suffer from oil starvation during startup.
Oil Cooler: Lotus fitted oil coolers as an option. I used a Mocal system with a thermostatic sandwich plate between the filter and oil pump. The oil cooler should be mounted on wiggly metal brackets bolted to the chassis cross braces. Just to be different I mounted mine a piece of hardwood which was very easy to make and actually looks right!
Gearbox oil: For the Getrag I used the Lotus recommended oil of 20/50. This is contentious and there are pages and pages of discussion on the internet from owners of Getrags in BMW's and Jaguars as to which is the correct oil. The problem is that the Getrag can be very notchy until the oil is warmed up and tends to baulk into 2nd. Some people say some oils actually promote wear of the synchros due to dry running from cold. Some swear by MT90 fully synthetic. I have tried Amsoil and Castrol Synthetics (the BMW recommended oil I believe), but I have to say that Lotus's unusual recommendation of 20/50 is really good, and has the best synchro performance.
Trunnions: the eternal argument, oil or grease? I have discovered that other have done as I did - build with grease (LM) and subsequently top up with oil. As long as the whole assembly is lubricated and is not dry then you should be OK.
Cambelt: On 907 and older 912 engines the cambelt has square teeth. Change this belt every 24,000 miles or two years. If you buy a car then change it immediately unless you are 101% certain it is OK.