I recently noticed that the engine in pinging upon acceleration.  I checked for vacuum and fuel leaks but could not find anything after a complete tune-up.

I took apart the distributor and notice some broken plastic pieces on the trigger points, any idea as to what these may be?

I also noticed that the advance springs are quite different from one another, I have read that this is typical but could not find a definitive answer as to what are the correct springs. The distributor is from the original engine with an air pump and CAT, should the springs be replaced, if so what would be a good source

I also checked the vacuum canister and it holds a vacuum and retards/advances the plates.

Last question is there a better way to ground the two plates together, they are ok for now but it looks a bit tenuous?

Any help here would be appreciated, thanks,
Dan

What was the timing at idle and 2500 rpm's.
Any idea what the compression ratio is?

Not sure about the timing at idle but at 2500 it was set to 27 degrees BTDC. I did not build the engine but would suspect that the compression ratio is near stock as the engine was a stock rebuild by a trusted member of this group a while ago.

The pinging is a recent event I have had the engine for close to 10 years, very low miles < 6000.

I guess I need a better timing light to check the timing at different RPMs

The ground between the plates looks good enough. The car wouldn’t start if it wasn’t.