Timing Chain Tension (tensioner....)

[fightingtorque]

Got my old (spare, has some bits missing) engine on the bench looking at better ways of installing crank sensor.

I have taken the timing cover off and note that there is quite a bit of slack in the timing chain, I believe this is the main offender in terms of why these engines are rattly ( engine now in the car is also the same) so I will put a new chainset on anyway.

I was a little surprised that there is no kind of tensioning pad at all.  Minis that have a single chain have a product like this:

 http://www.minisport.com/mini-spare-parts/info_12G2621OE.html 

I think it might be neat to add one to the slack side of the chain, if there is room.

Did anybody else ever try this?

Is there a spec for how much slack there should be/  what is it like when chain is new?

Gav

[fightingtorque]

I got one of the mini ones.  It is a bit too wide to fit under the cover.  I can thin it a bit, also I might get the relevant area of the crank main bearing retainer machined a little thinner (like it is where it clears the chain).

Can the retainer be removed without disturbing the actual bearing?