300tdi timing belt info

Evening people. I am in the middle of refreshing a 300tdi to replace the failed lump in my disco.

Anyway I ordered a new belt, tensioner and idler using the vin number from the discovery I removed the new engine from. What I need to know is this. When fitting the new "up grade " kit that has smooth pulleys do I need to change the bottom crank sprocket to one with a shoulder to hold the belt in place. As there no shoulder on the crank sprocket as the old tensioner was the part that kept it all in line

Reason I ask this is if I don't I can't see what will hold the belt on apart from tension and I don't feel that is right.

Hope some one understands what I mean.

Definitely you need to replace the crank belt sprocket, if the original has no cheek plates the belt will be prone to running off and against the inside of the timing case.
This modified belt sprocket was a common upgrade for the early Tdi's, it should be available in a whole kit, belt, sprocket, tensioner, idler, also wise to replace the tensioner mount stud as they have been known to snap off in service with the same results as a broken belt.

As above, there will very little holding the belt on without the cheek plates. They are not expensive on the bay... cheaper than the postage on an old one here which you are welcome to... if you pay the postage (!!)

I bought the full kit the other day, during the process of replacing my pump, and it was about £50... so well worth it, as everything is new..

Well I talked to someone at turner engineering as that's where I bought the belt and parts from and they say you don't need to change the bottom crank sprocket to one with a lip. I think since I have one on my old engine I will use that just for my own peace of mind.