Engine is 2056 with Raby 9550 Cam and D-jet
I have the stock Bosch plugs with factory gap
Running Pertronix with flamethrower coil
Engine timing is dead on the nuts
Valves adjusted 0 lash (chromoly with swivel feet)
AFR is 12-13 on the freeway
Fuel pressure is 30psi
Car runs great and has a lot of power all the way up to the redline. Engine runs very cool, seems to be happy. I have noticed that on a longer drive pushing higher rpms for extended runs there is a tiny bit of pinging unless i push down or let off the throttle, it goes away. I know that any ping even a teeny tiny ping is bad. SO...
I put Ultra Premium fuel instead of the midgrade and its still there. Keep in mind I might not hear it for a few days, but if I want to drive like I stole it for over an hour it can be heard.
I would rather not retard the timing from spec, and I dont want octane booster. So I was reasearching plugs and found that some new plugs might do the trick.
Question is do I want colder or hotter to cure my preignition. Is changing the plug my next step? A colder plug will help the preignition?
Joseph
12-13 at highway is pretty darn rich... thats WOT mixture.
I'm not sure that heat range in the plug will help with ping
but maybe I don't know any better...
when you say timing is dead on, what number is that for you?
also I have found timing can very if a cheap or different timing light is used.
I have one light that is crap and measure a different timing than another.
so perhaps verifying timing with another light is not a bad idea too...
your compression and temp. effect pre-ignition, so maybe lowering the combustion temp will help..
each different brand of spark plug uses a different system to designate hotter/colder.
for example a bigger number means hotter in one brand and colder in another.
Pinging= Timing issue.
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