AQ171 Timing belt problems

I have been having problems with timing belts on my port AQ171. The first one stripped the teeth off at the crank gear and bent many of the valves. After rebuilding the new belt lasted an hour before it ripped in half, bending many more valves. Anyone have any ideas what might be causing this?
Why did they close the previous thread on this subject? Looks like some of the posters were getting close to some answers and were going to post new belt and tensioner solutions. Has anyone found a way to put in a spring tensioner with alternate belt? Maybe manual overtensioning could have been the problem with the belt getting ripped in half. Anyone have a tensioning tool they want to sell? Volvo Penta New part # 955228, old part # 1159660. Thank you for suggestions, Rick

Re: AQ171 Timing belt problems

The biggest problem I see with Volvo timing belts is rusted pulleys which will shred a new belt in no time. Did you replace them when the engine was rebuilt??

Re: AQ171 Timing belt problems

zbnutcase said:

The biggest problem I see with Volvo timing belts is rusted pulleys which will shred a new belt in no time. Did you replace them when the engine was rebuilt??

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On the first rebuild I cleaned off the rust on the cam and crank pulleys with a wire brush and phosphoric acid. They looked OK, not worn or pitted. I spray primed and painted the cam pulleys and teeth. I checked the tensioner pulley. It rotated smoothly so I reused it. That rebuild lasted about an hour. Other posts say you should change the $250 tensioner pulley every time you change the belt. I am replacing the tensioner pulley on the 2nd rebuild. Maybe I should replace the crank gear pulley also and guide shims even though they look OK. I am cleaning all the paint off of the cam gear teeth for the 2nd rebuild.

Another factor other than the belt possibly being too tight could be that I had a salt water leak from a crack in the back of the sea water strainer housing dripping down onto the timing belt. I got a new sea water strainer housing for this 2nd rebuild.

I will make sure the gear puleys are bare metal and dry this time.