Hi I have a pd170 bmn engine and the timing belt tensioner chucked it last week. Had an insert put in the head as the stud was ripped out and a new genuine belt kit fitted. It was timed up and started before it was built up and ran fine. When it was all built up it sounded like pressure blowing back through the intake (never heard this over the intercooler pipe being disconnected at first start). Drove it home tonight and it had hardly any power and now at idle it is hunting. Is it worth pinning the timing back up or is this possibly a bent valve? 

So has all the head gear been apart or have you just put the head back on, timed it up and prayed?

Nothing was stripped off. Just the timing side of it. Just wanted to see if the timing had jumped. But yeh pretty much praying there was no damage. 

@Chrissy050392 - After a timing jump like you describe, I'd suspect bent valves and/or chipped pistons and/or bent con rods and/or a bent crankshaft, and have also seen a broken camshaft!

 

The only way to effectively test even some of those if you've got the engine "running" again and don't want to have to take it down head off and fit another new cambelt is to carry out a compression test, and if you get low compression on one or more cylinders that means bent valves and/or chipped pistons.