When my car's hot (eg after a drag holding high revs for a bit), i get this knocking sound - probably 2 knocks every 3 seconds or so, and it's been getting worse. Now it's happening when the car's not even that hot and it's almost constant. I can feel it in the pedals/floor too... Does anyone have suggestions on what to check? I've had my head under the bonnet but it's heaps harder to hear there and i can't find the source... help :cry: it's a 5spd turbo incase it helps.

I have a feeling that a valve is sticking...

i was listening again tonight... sound is only when the car is hot, and it is more like every 1-2 seconds, but it's random. sometimes it goes twice quickly (1/2 a second apart), then it wont happen for a couple of seconds.... it sounds like it's coming from the rear of the head Some original photos have not been recovered yet.

what revs is it at , sounds like it could be a big end bearing also it might be ur water pump those are two id look at first also check it could be a broken engine or gbox mount , though i dont think heat would affect them much

this is at idle, i can't hear it much after say 2k revs.... it's on the dyno tomorrow so i guess i'll get a good look and try harder to work the bugger out.

id be wary of putting it on a dyno if u got noises like this , it could do lots more harm than good

Yeah the dyno will put a lot of stress on the engine, that knocking might be a weak point which may give when put under that kind of pressure.