Volvo: Volvo 850 Timing Marks, volvo 850, btdc

Question
Hi Ray. I have a 1997 Volvo 850 sedan. I've recently changed my water pump, timing tensioner (and roller) and t-idle roller. I am 95% sure I've lined everything up correctly prior to the removal of the belt (Camshaft marks on the top cover) but how can I check the Crankshaft gear for TDC (or BTDC) markings. Looking down at it, I could not really see any cut-outs or marks on the teeth. The engine runs a bit louder now and there is a 'vibrating' noise which starts around 3000 RPM (only while driving). Could the water pump cause this (it was a Hepu replacement, not Volvo)? The pump itself actually has more teeth on the gear than the Volvo one. What are your thoughts?

Answer
Krys,
I have used the Hepu pumps for a long time without any problems, so I do not think that is a problem. The way to line up the cams is to use the special tools that bolt to the rear of the cams and align them. Generaly you use the marks on the gears and crank to set it before removing the belt and then the new belt goes in the same position. You may want to have a Volvo teck check the car out just in case to be sure that other damage does not occure. The vibration will have to be felt and inspected before it will be able to be found. If the belt was far enough off you would have pistons hitting the valves.