Hello, I want to know if anyone can help me try and figure out the noises my Vette is making.
The car has a cam. It sounds like a knock or tap. Also, sounds like my rockers are dry. Oil pressure is good. No check engine light or codes.

I already replaced my exhaust manifolds and spark plugs. I checked rockers and springs. I am thinking that the o-ring for the pick up tube may be pinched, or a faulty lifter. Any information will be helpful.

 

You can pick up an auto stethoscope on amazon for like $6. May help you narrow things down.

 

WHATEVER you do, do NOT run it any further until you pull the valve covers and verify they're oiling!! If most are, and this is a first time start after putting in a cam and lifters, it may have to run 10 or 15 minutes to fully quiet down a semi pumped up lifter, to bleed all the air out. Did you soak the lifters for a day or 2 before assembly? Whatever you do, make sure you have oil pressure. I sure don't like that squealing sound!! If your gauge reads "0" at start, and goes to 45-55lbs when running, cold, you should be OK. But it only takes a few seconds without oil pressure to the lower end, like maybe 5 or so, and the rods, mains, and maybe the crankshaft, will be junk!!!!! You say you have oil pressure. How much pressure? If no rockers are oiling, I'd shut it off if it was me, and I'd be pulling the timing cover and then the pump pickup, to check the O-ring. Damn GM and aftermarket making different size/color O-rings!! Why in the Hell they didn't design all the pickup tubes/pumps to have identical O-rings, I'll never know. It didn't have to be this way. Anyway, if you changed the O-ring, did you replace it with the same identical O-ring? Same color? I have always bought my O-rings straight from GM. My 2000 C5 came with the blue O-ring. Who knows if another company's blue O-ring is the same thickness as my GM O-ring? I always use dial calipers to double check the O-ring thickness, inside and outside diameter, plus color match. Good luck......

 

Dame right, that's not normal to me but others will problem say that's normal. The way i look at it is if your double guessing it take it apart to check everything so you can sleep at night. If not, just drive and let the chips fall and see what happens.

 

That kinda sounded like an alternator bearing to me - when you moved close to the engine the noise seemed to be coming from the left to me. I would definitely get an automotive stethoscope and try to pinpoint it, or you could take off your serpentine belt and run it for a few seconds (on a cold engine) to see if the sound is coming from the belt drive.

 

alternator was exactly what I thought too.

 

Okay, I will be getting a stethoscope. I used a rubber hose and a funnel and couldn't hear anything unusual.

I don't like that belt squel either! I just replaced my belt tensioner and it's back...

Also, I didn't just put the cam in. It has been in the car for a while. I believe the knocking is piston slap? Once it warms up it sounds less noisy, but my rockers are so LOUD! I removed my valve covers and let it run for a minute and they are getting oil.

 

@RB211 Thanks for the info. I will check out the alternator. I'll remove the belt and see.

 

I might be wrong but, are we talking about 2 different issues here??? Which one are you guys talking about the winding(alt) or tapping (lifters) ?

 

I agree. If the rockers are so loud you notice them clacking, there is something wrong, especially if they are oiling and you have good oil pressure. If that is the alternator squealing, as some suspect,, remove the belt, and see if you can turn the pulley by hand......

 

It's always tough to diagnose from a cell phone video. iPhone at least tends to amplify the noise like crazy.
I took vids of mine and you would swear it was going to come apart.......yet it made 100's of 1/4 mile passes with no issues.
I've honestly never heard an LS with a decent cam sound like stock.

OP didn't mention if the cam upgrade was recent? Or if the car is new to him?
Was this cold or hot?

I noticed the squealing over the other noises. That is worth investigating. Folks have had that be a failed lifter......

Ron

 

Okay, so here is all the information I forgot to include.

The engine was cold for the video.
Oil pressure at startup is at about 60 PSI once it is fully warmed it stops at 47 PSI.
Cam upgrade is not recent, it was done a while ago, by the previous owner.
The knocking noise goes away after reaching 150 coolant temps. Also, the knocking quieted down a bit after removing the belt. The sound sounds like it is coming from the middle.

The squealing is coming from the alternator I believe. The noise goes away after warming up.


More than likely, I think it is a lifter, but I will see once I get the stethoscope.


The engine sounds less loud once warmed up, but there is still valve train noise, so is this normal for a cammed car with stock rockers (I will post a video)? Could the knocking/ticking be a piston slap?

 

So my next question is, is this normal valve train noise?

 

Your first post video i would said something is wrong but the other videos sound different as to normalish. lol. And on the videos just posted you're too close to the injectors which are changing the pitch off the noise because they make noise when firing. Here's my suggestions. Put a towel over the injectores take a video. 2ed hold at 2k and last try heavier weight oil. Forget about winding alt that's the less of your problems. Obioves your loosing sleep over this so, this is what i would do. If your not comfortable withdoing these test cool its your car.

 

I'm gonna agree with RONSSNOVA. A cell phone recording can be misleading. Didnt realize you have an aftermarket cam I don't hear much difference in the 2 vids, only the reduced squealing is noticeable in the 2nd vid. With that oil pressure, and if all 16 rockers are oiling, run it like you stole it!! LS motors aren't that quiet stock, though most noise stock is from injectors firing. I have a built LS7 in my C5, and there is one lifter that clicks until the engine AND oil, are warmed up. Warmed up meaning 180°+ coolant temps, and 170° oil temps. You wouldn't have this kind of oil pressure if the O-ring was pinched........