My car's been running really well lately (chirped the tires in 2nd which it's never done before). However there's a seemingly intermittent loss of power at WOT accompanied by a ticking sound. I was getting some knock counts a while ago, but haven't gotten a chance to do a datalog while the loss of power occurs. My current suspicion is that something is tapping the frame, such as my loose AIR tube for the cat, and making it think there's knock when there isn't. Just in case, can anyone describe what actual knock sounds like?

 

Assuming you're talking about spark knock. Spark knock I've heard kinda sounds like shacking a tin can half full of marbles around under the hood.

 

Yes spark knock. I'm unfortunately aware of what rod knock sounds like .

 

It sounds like somebody with a hammer is trying to get your attention from inside the motor by banging some hollow metal poles.

 

Sounds rather more like a weeeeeeeek valve spring allowing a lifter to pump up. A frequent occurrence with worn-out stock springs.

 

Shouldn't be valve springs, as this is a rebuilt motor that I installed probably less than 10K miles ago.

 

Rebuilt with "new" valve springs? Do the valve springs meet the seat pressure requirement of the camshaft? New springs with too light a seat pressure will act just like worn out valve springs.

 

That I cannot say, as I wasn't the one who rebuilt it. It was built by S&J engines, and should have new springs that should be sufficient for the wimpy stock cam. I would think if it was springs that it would do it all the time, but I can get some strong pulls at WOT without the ticking on occasion.

 

So lets say that theoretically there was a weak spring or other lifter noise causing issue: Is there an easy way to check for this? Would it make the same sound in neutral revving it to the same RPM range, or would being under load make a difference? I'm inclined to think that if it's a weak spring it would make the same sound regardless of load.

 

Puts on best pirate voice

"Arg , It sounds like the Devil in the depths of Hell itself , playin a skull with a set of crossbones"

 

Engine Knock sounds like $$$$$$$$$$$$$$.

 

It literally makes a pinging sound like a ball peen hammer on metal! You will know it for sure if you hear it.

 

I just received a "new" AIR tube for the cat which will stop it from rattling around. I think probably that will solve the knock counts but I'll have to wait until it's installed to find out.