OK Ill get right to it.
I gotta 94 LT1 Camaro. Last Setp I had to get my car smog. MY car was on one of those Smog dyno machines. IM sure you all have scene those.

As soon as I got my car back. I was hearing this KNOCKING/TAPPING noise in the motor. NOW at that time I had just gotten my tranny rebuilt and I thougt it might have been a cracked flywheel. Well took it back and it turned out that there was no Cracked flywheel at all.

I took the car to my GM tech guy locally here in SO cali. And said he thinks its a main bearing that went out while it was on the smog dyno.

Now THIS is what the car does in while driving and idle.

WHen I first start the car up. There IS NO KNOCK/TAPPING at ALL!!
ONly after Ten to 15 min when the motor gets warm is when the KNOCK/Tapping noise occurs.
While at idle and WARM. WHen I rev it up. you can Hear the KNOCK/Tapping niose REV with the motor. IN other words as the motor revs up. The knockin niose gets faster and as soon as I let off the PEdel. the KNOCK/Tapping goes back to normal just like Two hand put togather and clapping.

NOW WHILE this is happening. I have watched my OIL Pressure. and its UP and normal. There is NO Drop in my OIL PRessure at all. When i do my daily driving I have seen no problems with the oil pressure. I have Drove the car 600 miles round trip and then anoter 400 miles round trip to Vegas and NO PRoblems at all.
As Far as performance. That car still gets up and goes and still has its Torque. The only thing that I have noticed a change on is my TOP END
I recenctly TOOk it to the track And at the ENd of the1/4 it seem like the car was slowing down. LIKE it had no more in him LOL
WHich leads me to Believe that the KNOCK/TAPPING noise thass occuring INDEED might be a Valve spring or somthing in the TOP end.

I HOPE YOU Guys can Shed some light on this issue. on to what might be the problem. THANKS GUYS LATA
Chris
LT1CST@aol.com

 

First thing that comes to mind is lifters. Seen too many engines with colapsed lifters. Any reason why you don't think it's a lifter. Could always test an additive to see if it quiets down. If it does than you know for sure but if it doesn't quiet down you haven't proved anything.

Easy way to tell is take the valve cover off and check each push rod.

 

I agree with abouve I would check the valve train and see whats going on. I think it may be a lifter as well.

 

I'm gonig to have to agree with the previous two.. Pop the valve covers and take a look.

 

Anytime your hear taping you can assume lifters, but normaly they tap on start-up and go away when they pump up. You said you had good oil pressure which also leads me away from lifters. Did you some how over wrap motor in N or in the bleach box. You can pump up the lifters by runing ATF for 20 min or so. Sounds like a wrist pin to me. Does it sound like its coming from top or bottom of motor? It gets louder when you let off the gas? If so could be you bearings. Maybe a bent pushrod they also sound like taping


Wheres shoebox at im sure he will have some good ideas.

 

Thanks SO a Messed Up LIfter would that EFFECT my TOP END power? Also. I dont think its bottom end related cuase my oil pressure is good. Stays up all the time never goes down. Another Question is this pretty common for lifters to be messed up? And IF it is my lifters. Y is that when I firsrt start the car up in the mourning. THere is no Knock. ONly when I get the car warmed up Thanks
Chris

 

Last time I heard a noise like that it was a wrist pin. Oil pressure was fine.

 

IS there nay possiblity that it could be a ROD knock. And if so wouldnt my OIL PRessure Rise and DROP in the gages.
Chris
ttt