Quote Originally Posted by H.T View Post
I know that this thread is for data purposes and the mods can feel free to delete this post but I thought I would throw something up for you all to think about.

I am not a mechanical engineer or engineer of any sort, so don't shoot me down, but this is just a thought;

A conventional gasoline engine usually has say a alloy head and cast iron exhaust manifold that is sometimes connected flush to the heat without a gasket, sometimes with a gasket in between, no doubt these two have different properties in the way they are made up and in there molecule structure and have different heating/cooling characteristics....

I was informed that the head and the exhaust manifold are actually one piece on these motors now, despite being a carry over from the previous model.

The point I am trying to get to is, could it be possible that as it is ALL the same piece of alloy, could some of the heat that is meant to exit through the exhaust system be transferred back into the area of the head around the cylinder chamber and be causing the pre-ignition? I remember years ago coming across a crysler/mitsubishi motor that would develop a hot spot in the head and this would cause pre-ignition and even running on to an extend.

Again, I could be completely off track here, but these engines have that many sensors that if it had been a computer/software problem surely it would be able to rectify it....
Let me just say that all 2006 on FD1 & FD2 Civics have the Exhaust Manifold cast into to Cyl Head the same as the the current K24Z3 in the CU2, yet no such problems exist in the Civic. Mind you, they do not run 11:1 compression ratio.
Post combustion ignition within the Exhaust manifold is nothing new. There have been several model cars over the years that have had this problem occurring.
In my belief if this was the actual problem All K24Z3 engines would be effected, not just a few which is the case. I could use the same argument & suggest that if it was an actual pinging problem in theory it would be more pronounced on vehicles with a manual transmission as owners would tend to labour the engine more (not downshifting soon enough) which would place more load on the engine, subsequently increasing the chance of pinging. Pre Ignition has usually been associated with high load / low RPM.
I still believe it is a problem associated with the timing chain / tensioner, but again if this was the case one has to ask why Manual Transmission vehicles don't appear to be effected? Could it possibly be something within the Torque Converter or an Auto Trans problem?
All we can do is wait for Honda HQ to find the problem so that effected vehicles can be rectified.
I have no such problem in my CU2 Auto, & 2 others that I know of personally are not effected either. It will be interesting to find out what the problem is eventually.