My 840i has 140k on it, and I'm getting afraid that the engine wont last too much longer... Just need a post of what I need to do to make my engine last as long as possible.....

Do proper maintenance and it will last for long.

Do a leak down. It will give you good info on the general health of the motor. With proper maintenance easily goes 200k+.

You've got the M60 4.0 which has double row timing chains so no real worries there... I've never heard of one breaking under normal use. Good synthetic oil. Don't let it get close to overheating, the heads will warp in one of your New York minutes. Call the dealer and give your VIN to see if the block was changed under the warranty program regarding the Nikasil issue, you might get a nice surprise as they seem to have been done a lot around 60-70k. Mine has 180k and was replaced at 78k. These are strong, well engineered motors, although a few would cite a fundamental design flaw regarding 4 missing cylinders.......:stickoutt The oil pump bolts have a tendency to work loose, worth the price of a gasket to check. I'd be more concerned with the peripherals on the engine.

You've got the M60 4.0 which has double row timing chains so no real worries there... I've never heard of one breaking under normal use. Good synthetic oil. Don't let it get close to overheating, the heads will warp in one of your New York minutes. Call the dealer and give your VIN to see if the block was changed under the warranty program regarding the Nikasil issue, you might get a nice surprise as they seem to have been done a lot around 60-70k. Mine has 180k and was replaced at 78k. These are strong, well engineered motors, although a few would cite a fundamental design flaw regarding 4 missing cylinders.......:stickoutt The oil pump bolts have a tendency to work loose, worth the price of a gasket to check. I'd be more concerned with the peripherals on the engine.
Eh, our V8s make up for it with the extra 8 valves. :stickoutt

Should last well over 200k depending on fuel, driving style and regualar maintenance.

toss the engine, rebuild you trans and keep going! (When it goes bad!)


Theres always the 4.4L obd2-to-obd1 conversion...

There is one e31 in SoCal area that was upgraded to the modern 4.4L, along with a 6 speed M5 transmission. It's a rocket!