93 prelude h22a1 knocking sound help
 

Just today as i was driving home from work i noticed when i was stopped the idle of my car felt weird, it felt more rumbly than usual. when i got home i pulled into garage lifted hood to see whatsup. well i did realize i have this "popcorn like sound" how popcorn sounds when its made in a machine as if sumthing is knocking (i dont think i heard this sound before). im thinking some kind of timing is off but i am not sure. for you experienced car owners out there im just wondering if any of you can help me figure what may be the problem thanks. btw i already checked oil level and its good, my spark plugs have been replaced 1000km ago and my spark plug wires as well.

Is the sound coming from the head area or down lower near the oil pan? If you take a screw driver and hold it to the engine you can listen to the end of the driver and try to locate where the sound is coming from. If its the head you might need a valve adjustment... if its the block you might have more issues.

Berz out.

without the screw driver tip im pretty certain the sound is coming from the head. it sounds very much like a valve is knocking right under the valve cover.

So this just happened? Are you confident with pulling off your valve cover and maybe checking out rocker arms and maybe doing a valve adjustment? It should be cold on that car for the valve adjustment but if the noise is that loud something should stand out I would think.

brought to shop awhile ago they just said sound is fine, all hondas make a tick, and that this prelude in particular just has that sound. the boss at the shop used to own this car previously and said his was even louder. he said valve adjustment may make it quiet .. for awhile but with time it will come back and only get louder so i guess that sound is fine although it doesnt sound fine.

Yes they do all pretty much tick for sure but it sounded like it was a new problem for you. I can't remember off hand what the gap was on those but it was small. None the less you should be doing a valve adjustment around every 24k on those if I remember right so it wouldn't hurt. It's not normally a loose valve that is the doing any damage but i know the ticking can drive one nuts.

intake .004 ex .007
i think the vtec engines are .007 in, ex .007-.008
I know alot of twin cam preludes make that ticking sound, that sounds like one valve is too loose. In the past, I've checked valve clearences and other possible things that can make that noise. Still a bit a a mystery to me. Doesn't seem to effect how it runs or the drivability though. Its when the valves are tight is when there's problems.

Another tech once told me the noise is from the valve being a little bent...on the twin cam, non vtec engines, when you adjust the valves, when you loosen that lock nut, watch how it puts sideways pressure on the valve stem. His theory was that is enough to tweek the stem and cause the tick noise. I'm doubting that cause the vtec engine valve adjust doesnt put the valve stems under that bending pressure.