Timing belt procedure: BRM vs 2.0t gasoline

I was just reviewing the timing belt replacement procedures in my Bentley for the 2.0t gasser. There is no requirement to lock down the cam or the crank (nor are there any special tools to do so). Just make sure they're lined up on the tdc marks, put the belt on, and turn the crank 2x to verify.

My question is, what necessitates the locking of the cam and crank on the diesel engine and not on the gasoline engine?

I'm guessing it's because the diesel engine has tighter tolerances and less room for error.

(I'm not trying to get out of following the correct procedures, just curious.)

Also wondered the similar: can you just align to TDC (on the flywheel), lock the CAM with a drill bit and the lock the flywheel teeth with some pliers or a screwdriver in order to replace the belt?

I would guess the higher compression of the diesel makes it more likely that the cams or the crank would move while you're trying to line things up, although I must say it surprises me there's no requirement to lock things up in the 2.0t gas engine as well.

Some gas engines do require a similar locking function of the cams, and cam sprockets loosened to rotate freely.. the V6 and V8s for instance.

Personally, I wish they were ALL like that as it makes the job so much easier.... you needn't fight with lining up anything while you are actually putting the belt on, as it stays put.

The 2.0t has a similar setup as the 1.8t before it, and is equally as lame.