Cam Timing

Did you use a slave cover to adjust the chain ? 

Is it this simple ? 

Yes as long as the dots are the proper dots.

The best chain is from The Chainman ie the Mercedes Timing chain made by Iwis, run in already so not need for the 1000 mile chain readjust and the biggest pins/bush possible to reduce wear long term.

Hello if you haven't  disturbed the intermediate gear off then yes it is that simple, but there are dots to align on the crankshaft  and intermediate pinions if you have. 

RGM sell a device to hold the end of the spindle to act as the dummy timing cover described in the manuals. Especially if the spindle is not tight. Incidentally there is a hard washer behind the pinion and it can fall out and be lost and forgotten or very difficult to replace without removing the chain(s) if the spindle comes out next time you remove the cover.

The slightly loose spindle  housing in the case  is not a problem in use but does make the chain adjustment less reliable so the use of a slave cover is helpfull .

"I decided to tidy my 72 commando by fitting a new style timing cover to incorporate an anti drain valve "

"One reason behind new case was so I could check the chain through the inspection hole ."

72 commando is 200K series and originally recirculation OPV style , indication you are using the MKIII timing chest OPV vent style cover on a 200K engine?

Hopefully you are clear on the modification steps to make them compatible.

You have to block off the old OPRV dump route in the timing side crankcase, a 1/4 UNC grub screw with loctite is all that's needed as the hole in the crankcase is already threaded. With oil in the tank and the timing cover off its the hole the oil leaks from. 

I have just checked my Mk3 crankcase and it still has the threaded drilling, which is not blanked and has not been disturbed during my ownership.  The timing cover has a blank casting that aligns with the crankcase drilling.  As the crankcase drilling is only into the gravity oil feed gallery to the pump, the timing cover gasket alone should be more than adequate to seal it without need for a grub screw.

Also, given that the PRV spill would just have dumped into the delivery pump inlet gallery, it would not affect the timing cover anti wet dumping valve on the high pressure side of the pump, so the reason for blanking is still not clear.  Perhaps the PRV spill.could cause leakage if the gasket was in poor condition?

Andy

It's a potential wet sump route as are the shafts in the pump between the feedside and the return side which can be fixed by machining the pump body for O rings.