Wow, a bit hard to read. Please take this as the constructive criticism that it is: Write in sentences with proper punctuation and capitalization.
Ok, several problems with your plan.
-In any case 8/2 is NOT acceptable for a 120/240V sub-panel. You need a neutral and an equipment ground run with the hot conductors. For a sun-panel it makes absolutely no sense to run just a 120V feeder. For not much more money run X/3 cable and you will double your capacity and have the future capability to run 240V loads.
-#8 NM or UF cable is NOT acceptable for a 50A feeder. You'd need #6 and this will allow you to run up to a 60A feeder.
-The ground rod is NOT for an equipment ground, so it has NOTHING to do with the bare wire run with the circuit.
-The neutral in a sub-panel is now always isolated from the grounding. I have no idea what you mean by "dead", but it does have to terminate on it's own neutral bar. Most likely you'll have to purchase and install a separate ground bar.
-Question, is the garage attached or detached? If attached, NO ground rod is required or needed. If detached, at least one ground rod and a main disconnect (main breaker typically) is/are required.
This is a quick synopsis of this install. There are many codes involved with running the cable and terminating things. PLEASE read up on doing this job and know what you are doing BEFORE you do it, or considering having it done by a pro.