Tonight I pulled the belt of my S/C in preparation of a bigger pulley. Then I washed the truck because I don't have the socket to remove the pulley, so I left the pulley and cage on without the belt. After washing it, I took it down the road to dry it off.

#1 Man was it weak. I hope all 5.4's don't feel like that.

#2 And most importantly....Most of you guy's with the '99's and '00's know what the truck sounds like when cold with a chip at about 1/2 throttle. The infamous "braaaaaaapppppp" noise as it's accelerating right before the shift. I'm here to tell you, you wouldn't believe your ears if you heard it without the S/C belt. (no boost) It "braaappped" for MANY seconds under a load regardless of throttle position before the shifts. In fact, the more throttle I gave it, the worse the noise was and the longer it did it. It sounds like 1 of the cylinders is a jackhammer and I don't know why. All I know is when it's hot and under a tremendous load (supercharger) it doesn't do it. Or at least as badly.

Now I know there's a lot of tech's, engineers, engine builders, and etc on this board that know their stuff, so really I'd like for some of you "thinkers" to put your brain at work. LOL, yeah, sort of. This is a REALLY bad noise and I think it might be responsible for many untimely deaths of L engines that we've read about over the last many months. I've got a good engine and really don't want to lose it. Is it a rod bearing like 'alphadoggy's' was or is it piston slap? Or is it a lean cylinder because of one intake runner being different in some way? I'm out of ideas and would really like your help. Yes, I've built many engines. One was featured in a magazine, so I too, know my stuff. But this one really puzzles me. What is this noise? Does anyone know? It's awful.

Jim

 

Ouch! It's the L death rattle - I'm no automotive engineer but I'm betting piston slap

I have a similar sound with my '00, hopefully it won't just blow apart. I wonder if there is a way to find out definitively before a major problem occurs so that a new motor could be had under warranty??

 

It sounds like the noise that alphadoggy described, just before it spun #5 rod bearing.

Jim, how did the cooler come out?

 

Hard to get air into the motor without the impeller blades in the S/C rotating. Remember your intake is designed with the blower in mind. If the impeller blades arent spinning you are moving very little air into the motor.

 

Jay,

The cooler came out great, but I haven't tested it yet. Tracks don't come easy where I live and before I make the long drive, I want great weather.

ZorPrime,

You're right about getting less air. That might explain the lower power, but man, what a noise. I thought it was bad before, but this is unthinkable. Like I said above, it sounds like a jackhammer. For the life of me, I can't figure out why it only makes it at a certain power level. In other words, half throttle with the S/C working and a chip installed is probably = full throttle with a chip and no S/C. Full throttle on my truck with everything installed sounds great. I would think if something were about to go, it would sound really bad at full throttle.

DB,

My "gut" is killing me right now. I hope we're both wrong.

Jim