2000 Hyundai Elantra Engine cranks but wont start

Since the timing belt was off, suspect bent valves causing the loss of compression. Thank you for providing good information. The next place to turn is a cylinder leakage test. That involves putting each cylinder, one at a time, on top dead center on the compression stroke, then applying regulated compressed air through the tester into the spark plug hole. The tester will indicate the percent of leakage, and you can listen for where the leakage is occurring:

1. Tail pipe - bent exhaust valve.
2. Air intake / throttle body - bent intake valve
3. Oil fill cap - worn piston rings.
4. Bubbles in radiator or reservoir - leaking head gasket or cracked head.

If you didn't replace the timing belt, consider doing so. It jumped for a reason, usually because a few teeth are missing.

Caradiodoc

Dandy observation. How did you discover the broken dowel pin? This is actually a fairly common problem with Dodge Neons but those are interference engines. The Engine Computer sees the camshaft and crankshaft position sensors out-of-sync and shuts the engine down to prevent engine damage.

It sounds like your engine is not an interference engine so no valves got damaged. You don't have to replace the camshaft or sprocket. The pin usually isn't too hard to remove. Sometimes you can use epoxy to glue a piece of wire to the pin, then pull it out. Another method is to use a wire feed welder to weld a small bolt to the pin. The hole in the sprocket usually goes all the way through, so you can just punch the pin out.

Caradiodoc