DOH said:This task is really involved and should be left to a competent mechanic, who ideally that has done a 1.7 Puma engine previously.
In view of your struggles to solve basic tasks such as sealing off a leaking exhaust manifold gasket and then ordering the wrong sized nuts, despite my warnings to check what size they are first , I would strongly recommend you do not tackle this task.
Barry is right in the fact that you really need to know what you are doing, as if you get it wrong, you will do extensive damage to your engine and end up scrapping the car.
Thanks for your condescending 'advice' that I do not tackle the job because it's too complicated for me.
I'm pleased to report that I've successfully changed the belt and tensioner and both me and the car are still alive.
I would agree with anyone who says it's not an easy job. It is quite involved, fortunately I wasn't in a hurry and I was able to take my time.
My advice to anyone tackling this is you do not need any special tools. Even the cam setting tool can be made from a bit of 3mm aluminium plate.
Lock the crank on the flywheel as described. I couldn't get a 6mm key in mine but a 5mm key did the job.
I cobbled together a puller using some old aluminium window runner and some bolts/washers. But one of those tripod puller things would probably work.
If you have strut braces top and bottom, remove the engine mount and rest the sump on the bottom suspension brace. Then you'll be able to lift the rocker cover off high enough upwards to remove it.
I changed the cam and crank seals while in there, they are cheap enough and easy enough so you may as well.
Last year I changed water pump separately, but having done both it's definitely easier to change belt and pump in the same 'sitting' even though the timing belt doesn't drive the pump.
Finally all I'd say is make sure you have a good selection of 10, 12, 13mm ring spanners and combination spanners. And sockets etc. There's not much room to manoeuvre in there.
You don't need to change the whole tensioner assembly, just the pulley. I've posted the part ref on a different thread.
My parts probably cost around £50 for Gates belt, tensioner pulley and 3x seals.