Timing chain check up

[mickeytwonames]

I'm taking the engine out for a clutch replacement and while I'm doing so am replacing the water pump. I have brought a timing chain replacement kit - but following the wise words of "bmcecosse" I won't replace it unless something is very wrong (iIm the man that thinks he knows what he's doing but is now old enough to know that's not true if it's the first time I do something) I presume it's OK to take the cover off to check it over but WHAT should one look for?
And if the chain is slack and DOES need replacing how can one ensure the timing is not mucked up?

[mike.perry]

Get a workshop manual and follow the instructions for lining up the timing marks.

[bmcecosse]

The chain WILL be slack. Be sure to slacken the starter dog using the starter motor BEFORE you take the engine out. Changing is easy - turn the engine so the dots line up - remove the sprockets and chain - fit new 'tensioner' rings to the cam sprocket - refit with new chain. Just make SURE the engine is not turned while the chain is being removed/refitted. At least the small crank sprocket will be seriously worn -sharp teeth - it does twice the work of the large sprocket.

[dellerie]

or fit a duplex and forget those silly rubber rings and chain rattle for the next 50 years

[bmcecosse]

Ahh but sadly duplex doesn't eliminate chain noise in the long term. Of course it works at first - because everything is new. For long lasting quiet you need the Mini simplex kit with rubber tensioner. Now that does work! Duplex is for fancy high=lift cam and strong/double valve springs.

[dellerie]

i reckon my duplex has been on my car 20 years now and its as quiet as the day i fitted it. one of the best upgrades you can do

[mike.perry]

The Duplex chain works on my engine but then side valves had them as standard.

[bmcecosse]

[mickeytwonames]

Thanks - I've taken the starter motor off so slackening the dog thingy might be problematic - is it going to cause real problems?

I'm down and dirty right now with the engine hanging from a makeshift gantry

[bmcecosse]

Yes - it will be difficult - take care you don't bend the nose of the crankshaft........