Engine rebuild? on 1990 Volvo 240

My son's 90 Volvo 240 is making a loud clacking sound. It will start and the overhead cam turns but the clacking is deafening. I pulled the cam cover and the lifters are moving. Broken rod or valve? Could it have fallen inside the cylinder well? Possible a broken piston arm? What would the cost of a rebuild be? Thanks.

Asked by for the 1990 Volvo 240
This is hard to know why it is so noisy without hearing it and see it first hand. You'll want to have a shop look at this for a diagnosis, and then an estimate can be provided. If the engine needs rebuilding, you may be better off getting a used engine.
Find a good Volvo Independent shop and have it checked out: http://repairpal.com/directory?address=95603&car_brand_names=Volvo
2 answers
I have seen some 240 volvos break valve srings.