phxscooby101

Well everyone I think I am going down that road that I hear on this board so much...

I bought the car 3 weeks ago and the previous owner just did a rebuild, with .030 over stock and new bearing with new rods, 1.5 harland rockers, new valves, 3 angle valve.. etc basicly all new heads.
Intake honed, exhaust honed, new fuel pump, adjustadle reg, new svo 24lb injector, custom chip.

So I take the car out for a ride and get on it, nothing out of the ordinary.. and when I get home I hear a slight whine like a bearing grind and slight knock,so let it idle so more and shut it down.

About 20 min later I start her up and it whines intermidately not a constant, and the idle is iradic with some knock I THINK.
Also it sounds like it's coming from the passenger side more.

After I turned it off sizzling sound on that side from the head???

Car: 1992 with 29k 6 speed

Possiblity: Spun bearing I hope not but..
Bent rod?
Bad rocker arm? but the whine is not good
Options?

Should I try to start her up while she is cold and see if I get the same results? I am calling the guy that did the rebuild and see what he thinks but it's not sounding healthy.

I would like everyone's input, Thanks Chad

kittmaster

sounds like typical ZF6 noise to me.

If the car is at a stand still in neutral and you press in the clutch does the sound go away?

I have a ZF6 also and it sounds like a knock, but trust me is your noise stops when the clutch is pushed to the floor, your good to go and have nothing to worry about. IF you push it in and the noise is still there, then I'd say worry

This issue will well documented if it is clutch noise.

Chris

phxscooby101

The car is in neutral idling. It's defintely not the tranny.
Thanks chad

LD85

Send me your email and I'll send you an video of a spun bearing at idle from my 85

LD85

I hope the vid's helped!

FD2BLK

Not saying it is the trany but the ZF makes more noise in neutral while idling with the clutch out. Try as the other poster stated presing the clutch in to see if the niosew goes away. How is your oil presure? Low oil presure is a tell tale indication of a spun bearing

phxscooby101

Well comparing what it normally sounds like and the way it did after the ride, it never sounded like this.

Oil pressure was normal but I did notice it was higher in temp than normal like 255 normal for my car is 245?? maybe the oil broke down? Thanks chad

phxscooby101

Id85: Thats very close to the sound I am hearing

So is it wise to start it up while it is cold to see if it does the same noise, or will it just make for more damage??

Also it is at a friends house and I want to tow it to my house, can you tow it or is it flat bed only? Thanks Chad

LD85

In my opinion, IF it is a bearing, then the damage is already done.

Flat bed is how I would do it.

conv90

...probably an allready spun bearing "cured " with new oversized bearing just to sell the car...

phxscooby101

conv90:explain what is that? Thanks chad

LD85

Are you mechanically inclined?

http://forums.corvetteforum.com/showthread.php?t=957542

conv90

just to be
If the old owner detected a spun bearing condition, He can sell the car saying the car has a spun bearing.
or...
He can say that the car is in perfect condition with a recent rebuild.
He drop the pan, replace the old worn bearings with a incresed size and put in a thicker oil or a a product good for this pourpose.
When started, the car acts like new (without hammerig noise) and the car can perform up to 100 miles or more without noise.
I'm not saying this is your case.
for sure this was my case in the 2001 when I bought my car.
-Beppe-

gate1257

Will the oil pressure fluctuate with a spun bearing?

My pressure stays normal until the engine gets hot, and then it drops to 0 at idle.

Shore

If you have a spun bearing then you will most defintily have very bad oil pressure....they go hand in hand.
1...what's cold oil pressure at?
2..what's fully warm(not full temp but full warm) oil pressure?
3..If it has zero oil pressure when fully warm and cold low pressure then you have a spun bearing.\\

Here's the norm for oil pressure...cold should be around 60-75ish at like idle.
Warm oil (driven for a bit) should be like 30-40 at idle....anywhere close is good.

phxscooby101

Mine was alway's 70sh on start up and 30 to 40 fully warmed up and would go up as you increase the throttle load.

I talked to the mechanic and he said they did a full rebuild with clevic bearing. I want to record the noise and put it on here to see what everyone thinks.

I'm not sure what to do next? Chad

phxscooby101

Engine: .030 overbore(355 CID) .030 over pistons, Manley rings, stock rods, Clevite bearings.
Comp Cam 112 degree cam profile 224/226 with 515 lift. Comp Cams roller lifters.
Heads: hand ported ,blended, portmatched w/ Manley Proflow stainless steel valves, 2.02 intake, 1.56 exhausts. 3 angle valve job,Erson springs, neoprene seals, Harlan Sharp aluminum 1.5 roller rockers.
Exhaust: Magna flow mufflers,
Exhaust manifolds ExtrudeHoned, port matched.
Fuel: 24lb SVO injectors,adjustable fuel regulator, stock in-tank fuel pump
Chip: Z-industries
Throttle Body: 52 MM TPIS
Intake manifold: ExtrudeHoned, port matched
TPS recalibrator
Ram air system w/K&N filter

Here is the list of everything done on the car. Later Chad

gate1257

When first started in the morning, oil pressure is around 60, and stays normal until it's been driven for a while.

After driving it for about 20 minutes, the oil pressure starts to drop and hits 0 at idle, rising to around 20 psi when accelerating.

I swear the belt starts to squeal when the oil pressure starts to drop. I don't know how they are connected, and I'm almost positive it's not the sound of a bearing.

LD85

Zero is never good, you unfortunately are in need of new bearings.

pablocruise

Does the sound speed up or slow down along with the RPM's?

Crankshaft speed or camshaft speed?
(the crank revs twice as fast as the cam)