I would start by getting a more traditional automobile engine, if you are trying to use a worm to power your rig, the ticking noise is probably the least of your problems. There's no way you can roll anything bigger than factory tires with that set up.
On second thought, most of the worms I have encountered don't really make any noise, let alone a ticking noise, so maybe it's not actually a real worm you have there? I would take it to a licensed fisherman and have him take a look at it for you first.
That's called root-cause analysis, baby!