300TDI Timing belt idler - case chamfer

Hi all,
Fitting a new timing belt kit (INA/Bearmach sprocket, tensioner, idler + Dayco belt).
Previous owner had fitted the modified parts (crank sprocket with belt guides, idler with no guides) but they hadn't modified the case.

According to landrover the case should be modified too - where the idler stud screws into casing a 2mm x 45 Degree chamfer is required.
I am buying a 45 degree countersink and will drill it 2mm deep - but why is this mod required?
Is it for the waist of the new stud to nestle into nicely?

Many thanks from a confused enthusiast

someones case with the chamfer:



My case without the chamfer

Just a guess but its probably to remove any potential burrs or surface distortion from the previous bolt style installation and to assist stud fitting, the tensioner can also sit flat on the machined surface

Maybe also so that the stud has more strength by having the waist sitting snugly in the chamfer?

Wish they would tell you why to modify :/

Just about to do this on my 300tdi that has not had it done.
Can the chamfer be done with a countersink in a hand drill or does the case have to come off to be done in a pedestal drill?
Cheers
Rich

I would think it could be done carefully in situ, the countersink isn't being used as a reference or to align anything it just aids stud insertion or removes any roughness around the thread hole. Make sure you get all the swarf out.

Thats what I was hoping to hear!
Thanks!

Rich

Ps sorry for hijacking!

Quick question

Can the idler roller stud be reused after chamfering the case or do I need to get a new one? If so, what is the part number?

I bought a 'kit' but it doesnt include the stud or the cap head bolt for the tensioner

Cheers,

Rich