pauly wrote:
Don't some engines run without BS bearings ? I'd be tempted to reinforce the oil pickup pipe and not worry about the balancer belt.
I disagree....if you want the engine to last you need the balance shaft belt....yes some racers remove the belt to gain a little extra power (approx 8bhp) but they will rebuild their engine on a regular basis whereas a car on the road wants to avoid such things. The belt does a wonderful job of balancing the piston side forces at the top of their stroke, this is critical for an engine with such a large bore.
There is a bearing shell iirc about 2/3rds back along the shaft, perhaps this is the problem although I have never heard of a balance shaft seizing up, however I guess it depends on servicing and which oil was used, when I changed mine they showed some wear but not much considering the mileage covered. It's also possible that there's a problem in the front housing too, whichever it is imho it's best to remove the engine, I don't say this lightly as it's a big job with many costs involved.
Pete