Ran it hard, now making new/odd noise???

[raw23062]

Hey guys, still learning these cars so I thought I'd check with you before I start digging. I took a guy for a ride last night and buzzed her up to around 6500-6800 rpm through 1st and second and I did it two times. The first run, I experienced what I would guess was a little bit of belt slip maybe?? Kind of layed down a bit and made a lower pitched whine than I've ever heard. (It's got the 2.3 Whipple) It doesn't whine much to begin with, so this low, quick whine was odd because you don't get much whine in the cabin at all period. The second run, it didn't do it and it felt great. When I got back in the car to head home, I noticed under light acceleration what I would call what sounded like slight spark knock when going through the gears...odd...never heard that before. I noticed it pretty much all the way home. I needed fuel, so I stopped and filled it up..upon heading to the house, I heard it at first but then it seemed to go away a little.....when I put it in the garage, I left it running and popped the hood and turned the motor up a few times from under the hood and the sound is like a slight whistle/belt slip noise that it's never mde before when doing this... and Im only bumping the throttle from idle to around 2500-3k max. Not enough to make the belt slip I wouldn't think...??? It's hard making good sense of it all with long tube headers, 3 inch exhaust, race mufflers and no cats!! The last bit of helpful info I have is that when they put the 3.0 pulley from the 3.2, they removed the top idler, sighting not being able to get a belt size that allowed for it to remain....and I was told it wasn't needed. I have run the car hard a bunch since this change and had no issue, but it sure seems like that top idler makes the belt wrap around the blower much better....???? Thoughts?? And for you guys that love to point out the obvious, yes, I get that having the top idler would give a better belt wrap and be the prefered route....Im just looking for anyone who may point to another issue I might be experiencing with these symptoms. Thanks in advance guys, I appreciate it.

 

[Jimmysidecarr]

So there are two unusual noises, correct?

A low pitched whine, that could be belt related ----and a light throttle spark knock type of thing?

First thing, look for belt dust, if you have belt slip, you will have belt dust.

The low pitch whine should be fairly easy to find with either a stethoscope or suitable substitute, a long screwdriver, a length of hose,etc held to your ear and the other end to the test area.

In the event you can't figure out what the low whine is, remove the blower belt and start the car.
Check to see if the sound stopped, if the sound is gone with the belt off, you will need to put the belt back on and keep looking, because one of the things being spun by the belt is making the noise.
I also think you should just go ahead and buy a little longer belt and put that idler back on.

If the sound is still there with the blower belt off test tensioners and everything being spun by the inner belt.

Just as a side note: To prevent accidental lean outs, I think a good policy is to keep at least 1/4 tank of gas in it or don't use wot below that point.

On the spark knock sound pull a spark plug, get good light and a magnifying glass and check the center electrode insulator for very tiny metallic pepper spots.

If the insulator has no pepper you have not detonated on these plugs.....yet.
If there is pepper, you have.
If you have you need to find out why it detonated.
There a lot of different possible causes for detonation, you basically need to make sure NONE OF THEM are happening anymore.

Light throttle spark knock is unusual on these cars, but it's still bad, if that's what is happening.

Did the light throttle knock happen right after a fill up?

 

[mach1033]

U need to video it then post it here. I hope that knocking noise isnt a spun bearing. Drain your oil and see if there are any metal shavings. You will not see it on the dip stick all the time. The whine your talking about on the blower could be a vacuum leak. Check the black of the blower and make sure all the hoses are connected. It happended on my 2.3 and my 2.9 blower and it does make a whining sound but you also lose boost as well. Like Jimmy mentioned where there is belt slip there is dust they go hand in hand.

 

[Jomo1994z71]

I agree with the above posts, check your vacuum hoses, also...
You were going WOT with little fuel in the tank?

 

[mach1033]

I also forgot to mention. 6800 is pushing it for the stock valvetrain. My motor is getting rebuilt this month from pushing it to hard with 23lb of boost. I lived and I damn well learned what not to do again on a stock motor lol.

 

[raw23062]

So there are two unusual noises, correct?

A low pitched whine, that could be belt related ----and a light throttle spark knock type of thing?

First thing, look for belt dust, if you have belt slip, you will have belt dust.

The low pitch whine should be fairly easy to find with either a stethoscope or suitable substitute, a long screwdriver, a length of hose,etc held to your ear and the other end to the test area.

In the event you can't figure out what the low whine is, remove the blower belt and start the car.
Check to see if the sound stopped, if the sound is gone with the belt off, you will need to put the belt back on and keep looking, because one of the things being spun by the belt is making the noise.
I also think you should just go ahead and buy a little longer belt and put that idler back on.

If the sound is still there with the blower belt off test tensioners and everything being spun by the inner belt.

Just as a side note: To prevent accidental lean outs, I think a good policy is to keep at least 1/4 tank of gas in it or don't use wot below that point.

On the spark knock sound pull a spark plug, get good light and a magnifying glass and check the center electrode insulator for very tiny metallic pepper spots.

If the insulator has no pepper you have not detonated on these plugs.....yet.
If there is pepper, you have.
If you have you need to find out why it detonated.
There a lot of different possible causes for detonation, you basically need to make sure NONE OF THEM are happening anymore.

Light throttle spark knock is unusual on these cars, but it's still bad, if that's what is happening.

Did the light throttle knock happen right after a fill up?

Thanks ALOT Jimmy. Ok, I went out Saturday and started the car to figure this out and the ONLY noise present at idle or turning the motor up some is what I would describe as a high pitched chirp/whistle that gets louder when you turn the motor up....it's not constant....when at idle it will chirp in time with the revolutions and when the motor is turned up it gets louder and higher pitched. I removed the blower belt and it went away. I had a good friend come over and listen who is a 20+ year factory service tech who also has alot of high performance experience BUT NOT with these cars. His take was it was belt slip and he felt confident about that diagnosis. I did NOT see any dust to speak of but I haven't driven the car since this noise first started, other than about 5 miles home and I babied it all the way there...so maybe no dust yet?? I wasn't comfortable to begin with when that idler puley was removed, so my first order of business is to put it back on. Now, it seems to me like there is room with this current belt to put that pulley on...it would obviously use more of the tensioners travel to do so, but definitely not max out the tensioner. What am I looking for as far as the proper belt length?

With regard to running the car WOT with about 1/8-1/4 tank, yes, looking back, I really feel stupid for doing this and it really should have been common sense to not do it. I honestly didn't even think about it. All of my past cars have been rear sumpted and it wasn't an issue(still not a good idea) I just hope I didn't F anything up. That noise I heard that sounded like spark knock seems to be gone, but I haven't taken the car back out yet. Also, to answer your question, the "spark knock" noise I heard was when the fuel was low(not on E though) and was under very light acceleration....it seemed to go away shortly AFTER filling the car up. I still want to emphasize that pinpointing sounds on this car is really hampered by the noise level from the exhaust, so I could have been wrong but that's what it sounded like to me.

I need the longer bolt to put the pulley back on, so Im going to go pick that up today and install the idler pulley and then recheck the noises. If you can let me know what tolerance and travel I need to check to make sure the belt isn't TOO tight, that would be great. Thanks alot for your help, it's greatly appreciated.

Thanks to the others who have chimed in as well.

 

[raw23062]

I also forgot to mention. 6800 is pushing it for the stock valvetrain. My motor is getting rebuilt this month from pushing it to hard with 23lb of boost. I lived and I damn well learned what not to do again on a stock motor lol.

Thanks man, appreciate the comments. Just a note, Im running 17psi on a fully built motor. Nothing stock. HOPEFULLY I didn't screw anything up by the low fuel WOT.....dumb....really really dumb. :nonono:

 

[raw23062]

Another question I meant to ask is what is the best gauge to monitor lean/rich conditions on the market? There are certain to be opinons on this on here. Prob should have googled before asking, but I am curious what Jimmy(and others) have to say. Thanks.

 

[Jimmysidecarr]

If you know what your belt size is now just buy the next size up.
When I change something that requires a belt change, I buy three belts sized in sequence with the one I think it is going to be right in the middle.
I make sure I can return the wrong ones before I make the purchase.

I have not researched wide bands.

 

[raw23062]

Gotcha, well that certainly makes sense. I don't know the size, but I would assume its on the belt writing somewhere?? Does the tensioner need to be removed to get the belts off of these motors? Thanks again for the help.

 

[kingcobra8541]

No need to remove the tensioner just stick a 1/2 in ratchet in it to move it...

 

[raw23062]

Oh, ok...yeah that makes sense. At first glance I just saw there wasn't much room behind to slide belt out. I guess when you move it down it opens up behind. Makes sense. Thanks! Going to go get a few belts this afternoon. Thanks for the help guys.

 

[big dad]

You stated that the noise went away when you removed the blower belt. Remove the belt again and check your pullies for roughness or noise with the engine off of course. Just spin them by hand or take them off and feel the bearing while you turn them by hand.

 

[raw23062]

You stated that the noise went away when you removed the blower belt. Remove the belt again and check your pullies for roughness or noise with the engine off of course. Just spin them by hand or take them off and feel the bearing while you turn them by hand.

Yeah, true. I had to order the belts today, nobody had them. I spun all the pulleys by hand and they seem nice and smooth and tight but if it still makes the noise I will pull them and further inspect. Good idea. Thanks! Perfect night for a ride too.....