Wotcher all, OT-ish because it's not a landy engine, but I'm sure it applies just as well.
I'm getting what I *think* is knock or pinking in the pinz. At low revs under load if I put my foot down, I get a sound like a few bits of lead shot falling onto a solid chunk of metal, not a "ping" more of a rattle really. If I slacken off the throttle it goes away, or if I change down a gear to increase the revs it also goes away. It really only happens with low revs, WOT and when I'm going up a hill.
Does this sound like knocking/pinking to you, and if so I've read that older low-compression engines are often designed to withstand it as part of their normal daily life under the above conditions (up hill, WOT, low revs) and that on such engines I should only worry if it's happening all the time, e.g. on the flat. Any users of older petrol landies have any thoughts on this?
According to a chunk of text from a magazine apparently written by an engine designer, pre-ignition is something to worry about but you tend not to get a warning other than a blown piston, but with detonation, it happens after the main spark has fired and ignition has already begun so the piston is already on the way down. It's detonation that you can hear as pinking. Thing is I don't know what pinking sounds like but the situation this noise is happening under (WOT, low revs, engine under load) makes me think it is.
Cheers for any thoughts.