I really wish I had of found this earlier on , been a while now tuning away and was always suss on a pinging issues that just ran me around like I was it's little b--tch just because it could !
Anyway just wanted to share incase this helps some one out .
My ute with a 355 stroker , around the 10.4 comp mark , pretty small cam crow 4503 , banana manifold etc .
Had to gut the timing map from early on to eliminate a ping heard on acceleration . Left the ignition map pretty gutted for ages and as time went along had to remove more at points , seemingly at times a bit random , seem to get rid of it only to have it appear again at times , sort of baffled me why .
Made assumptions this was just tuning , comp too high for cam and cylinder pressure , I did a shitty job of porting heads and had managed to make a hop spot some where , etc etc etc . As time went on I did eliminate a few things . I put a thumper big cam in just because and figured well this will let the cyinder pressure escape and will cross that off the list only to have an issue with oil getting pumped into the inlet through the pcv and cause more issues . Still had ping present under light loads with a still gutted timing table . Put original cam back in and carried on.
The "ping" was not what I called normal just to clarify . I would say normal pinging is able to be replicated with the same throttle application and the same load , sort of over and over again if you so desired to . This wasn't really the same every time , seemed to have a bit of a mind of its own , and not a solid ping , sort of just could hear it barely but it was there . Drove me nuts .
Anyway the fix . I have a good known ignition module been built for me and tried a few others too . Good ignition wiring , earthing , etc . Moved negative wire out of loom between module and coil as this is a bit of a known issue , can cause inductive interferance between postive and negative power supply wires to module .
Anyway , the issue it seems has been the POS after market distributor all along . Mind you this thing has worked everytime for the whole time , always started , never really much issue to note other than the shitty random little ping .
I bought a cheap Bosch original dizzy to do up and just fininshed that and put it in today . Went driving a tuning and quickly found out I could pour another 5 degrees of timing in to the table across a broad range of cells with no ping . Performance is up and I still think there is plenty left yet to do to the map .
I hope this might help someone else as it has driven me nuts for quiet a while now .
cheers.
