I had the motor in my 1978 pinto wagon rebuilt in 1988. And about a year and a half ago I had the 4 speed manual transmission with a unit I was told had been rebuilt by students at a tech school. The guy who sold it to me said he was getting a Quaiffe Rocket for his pinto

 Anyway, Im having ticking and tapping noises. Now the one sound is probably a slightly loose rod, its barely audible when I first start the car. I had the person who rebuilt the motor listen to it two or thre years ago and he said thats what it was and it wasnt that bad to worry about. But someone I had listen to it more recently said it sounds like  awrist pin to him. Either way that more or less goes away.

 The next sound, is tapping like the engine is over advanced even though its now retarded to the point it takes three attempts to get it started when its cold. The  weeird thing is it only does this noise when the the engine is under a load, light acceleration or uphill. And if I shift from third to fourth it goes away. Im not sure if its vacuum related, or could a transmission make a similar sound in one gear?

 Third, is predetonation the sound like marbles in a can, when its even just warm out. It has never done this until the last 6 months or so. I tried using 91 octane as someine suggested, and it helped but didnt really stop it. I have the mixture set a little rich thinking it might help keep it from happening. Is this some condition (failure) in the engine that would cause it to be more prone to this all of a sudden? I really wonder about the gas.

 And now, as I shut the engine off, I hear a sort of scrape sound just as it stops.

 Wondering if its time for another rebuild, of course I find it hard to justify so much money since it still runs pretty well and doesnt seem to be lacking much power.

 Thinking about adding a temp gauge to see what it looks like when the pre detonation starts up. Can anyone suggest a good one or a certain type or type of installation or advice or tips on installing a temp gage.

 Just trying to tap into the knowledge base, any inputs will be appreciated.

 Edit: Anyone think a different heat  range plug or gap may be in order to deal with any of these issues?

 Maybe it goes away if I shift from 3rd to 4th though and that seems kind of weird