by Boghopper » Mon Nov 20, 2017 12:02 am
Of course the belt will deflect and stretch that's why they have a spring loaded tensioner to compensate for the discrepency as they age. And that's why Ford tell you to replace them. If you put the timing pin in the block and bring the crank web onto it with no.1 at T.D.C. in many cases the cam locking bar won't fit because the belt has stretched and the cam timing has retarded. The straight run (load side, on the top) on the belt isn't as tight as it once was and the cam isn't being turned quite enough to allow the bar to fit.
I had this happen to me last weekend on my Connect. The only way to advance the cam is to remove the belt with the crank pin still locking the crank and just ease the cam around a fraction to bring the cam to its rightful position, which is timed up with the crank, then you put the new belt back on and tension it. If you cannot be bothered locking the crank, then when you lock the cam off with the locking bar the crank timing will have advanced by whatever the cam was retarded by. You will just transfer the error from the cam to the crank. Why do you think Ford go to the bother of casting timing holes into the block that align with the crank web, because they were bored and had nothing better to do? No matter how many times you want to try and avoid this logic, it is the only way to correctly time the crank to the cam and correct any wear 60,000 miles has put on the belt. I also draw the cam sprocket off so as to allow the tensioner and belt to find their prime position before I adjust the tensioner and retighten the cam sprocket. And let me just say my van feels a great deal nippier than it did. It is eleven years old with 63,000 on the clock and it is the first time it has had the cam belt changed.