So, Just bought a samurai for pretty cheap actually and the engine has a knock which of course I know is not good and the guy said he set the valves and everything looked good on top. What I am wondering is The know gets a lot quieter with load on it, I.E. 4th gear and when you let off the accelerator it gets loud when when your cruising at just an idle the knock is super quiet. He said the distributor is messed up/. He says the vacuum advance is causing the knock. Is this possible? To me it sounds like a rod but every time I have heard a rod knocking its never gotten quiet under load like that. it has always gotten worse. What else I was wondering, is there a vin decoder to figure out what engine I have? How easy is it to just pick up a cheap new engine for these things? Everything else is oustanding condition.