If a cam shaft breaks, do you need a new motor?

Cam shafts don't just break. They are made of a large chunk of iron or steel. A broken camshaft happens because something has hit something inside the engine. Usually this is due to a timing belt or timing chain failure and the pistons have clashed with the valves. When this happens, your engine is junk. Get a new one.

Astrobuf

If a cam breaks, it could damage the engine by allowing the valves to contact the pistons in an interference engine. Camshafts rarely break because they do not have the stress like other components like a crankshaft, connecting rods etc. A camshaft timing belt or chain can wear out or break and cause the valves to contact the pistons, which is much more likely.

Cam shafts don't just break every day. In fact, it is very rare for a cam to break under normal use. If it did break, then it is sure to have caused some kind of internal damage to the engine, and it would probably be cheaper to replace the damaged engine with a used engine from another car..

Sounds like a Vauxhall "Family Zero" 1.0, 1.2, or 1.4 chain drive engine. They had an issue a couple of years ago with a few batches of engines having incorrect torque on cam bearings, and the cams broke opposite end to the drive sprockets. I have successfully fitted new cams into these engines, even though there were signs of "gaulding" on the cam bearings in the head casting, they ran no problem, and are still going. We need more info on this. Some engines kill themselves with this kind of failure, some work perfectly afterwards if fixed correctly. Examples of suicidal engines include Ford 1.8 Diesel and the PSA (Citroen/Peugeot) XUD range.

depends if it is an interference or noninterference motor. Camshafts rarely break ,are you sure its the camshaft ? probably the timing belt or chain

Its not under warranty ?it should be

No.

Even if it is interference. It will only bend the valves, might be some damage to the pistons if you were going very fast.