Timing Belt Alignment problems.
Posted: 06 Nov 2020, 11:19
Morning All,
My injection pump was leaking in December so took the bus to a diesel specialist who rebuilt the pump and refitted it with a new timing belt and tensioner (I supplied from Brickwerks).
In August, and a few hundred miles since the rebuild, the bus was hard to start, eventually grey mist on initial start-up, then black soot but fine when warm. Slow to pull away but picked up pace as I went through the gears, but next to no power up hills.
I found the pump was leaking again, but from a different place. But also on deeper inspection I found the timing belt was ruined and the covers were melted. The previous timing belt before the pump rebuild had no issues.
So the pump has been rebuilt a second time and now the timing belt overhangs one of the timing gears about 2mm. The current belt is new, and the correct size. None of the gears, pulleys or tensioners have any apparent play or end float, but I am going to use a straight edge to straddle the different pulleys to see if this would indicate any misalignment.
The mechanic assures me that the pump can only go in one place by design, there is no adjustment and it is seated correctly.
The only change to the timing belt set up is the pump being removed and re-fitted, twice!
What’s causing the misalignment?
I’m expecting the timing belt to sit centrally with no overhang on any of the gears/pulleys as. Is the overhang a problem and the cause of the near disaster with the previous belt?
Is it possible that a part has been left out when the pump was rebuilt and so shortened the length of the pump drive shaft?
Any ideas on how to get the belt to run true would be great!
Many thanks
Blakie
My injection pump was leaking in December so took the bus to a diesel specialist who rebuilt the pump and refitted it with a new timing belt and tensioner (I supplied from Brickwerks).
In August, and a few hundred miles since the rebuild, the bus was hard to start, eventually grey mist on initial start-up, then black soot but fine when warm. Slow to pull away but picked up pace as I went through the gears, but next to no power up hills.
I found the pump was leaking again, but from a different place. But also on deeper inspection I found the timing belt was ruined and the covers were melted. The previous timing belt before the pump rebuild had no issues.
So the pump has been rebuilt a second time and now the timing belt overhangs one of the timing gears about 2mm. The current belt is new, and the correct size. None of the gears, pulleys or tensioners have any apparent play or end float, but I am going to use a straight edge to straddle the different pulleys to see if this would indicate any misalignment.
The mechanic assures me that the pump can only go in one place by design, there is no adjustment and it is seated correctly.
The only change to the timing belt set up is the pump being removed and re-fitted, twice!
What’s causing the misalignment?
I’m expecting the timing belt to sit centrally with no overhang on any of the gears/pulleys as. Is the overhang a problem and the cause of the near disaster with the previous belt?
Is it possible that a part has been left out when the pump was rebuilt and so shortened the length of the pump drive shaft?
Any ideas on how to get the belt to run true would be great!
Many thanks
Blakie