Hey!

(first ... I'm from Poland, and i could make some mistakes when writing in english)

I've got a newly rebuilt LT1 with a stroker kit 383 (all forged, new oil pump, new bearings, rings etc.) ... stock cam, heads, and, valvetrain ... (those things would be changed later) ...

'95 Camaro Z/28 A4 ... 80k miles ... Hooker Cat-Back, LT's Pacesetter, Moroso CAI, LT4 KM ... new plugs, wires .. O2 sensors ...

Car is running great ... but when oil gets to its normal operating temp.
knocking/ticking is starting but only on idle, and sometimes on low rpm ...
when i rev it more than 1000rpm it stops (sound is getting faster with engine rev)(sometimes it gets to stop as fast as only touching the throttle) .. and returns few moments after it gets back to idle .. I belive this noise is from beneath VC's ... a strange thing is that when I take off the oil cap the knocking stops ... and after I put it on .. it didn't return for about 1min and then it is back ... this knocking/ticking sounds like some metal knockig on something

Mariusz Izdebski (gdansk Poland)

 

Backlash on a rocker arm(s) could be set too loose. If you still have the smog pump check valves mounted to your exhaust manifolds, they can work loose and cause a ticking noise.

 

No i have Pacesetter Long Tubes without AIR and EGR fittings ...

The rocker arm backlash, if it's that then i should re adjust valve lash??

 

Yes, re-adjust the rocker arms and you'll know right away if that is your problem. Do you know what rocker arms you have???

 

I'll do it ... but will opening the oil cap have anything to do with it ?? ... Like I said, when I open the oil cap while this ticking sound is present .. it stops immediately .. and it starts to knock/tick only when it reach its operating temp. ... shouldnt they knock all the time if they were badly adjusted ??

Rockers are stock ... this is '95 LT1

 

Adjust the rockers when the car is warmed up so you can make sure it wont be off when the oil gets to temp. When the oil warms up it thins out and loses some pressure, the loss of pressure in the lifter maybe causing the ticking...so just re-adjust while hot.

 

Also, even though you *think* the sound is coming from the valve covers, check and re-tighten all your header bolts. That happens to me sometimes, a bolt comes loose and makes a ticking from the leak.

 

Are the lifters stock too? Stock lifter can be set to 1/2 - 1 turn pass zero lash.

 

OK, I will try checking header bolts, and re-adjusting valve lash ...

But what about that weird thing with stopping the ticking/knocking sound after removing oil cap ?? anybody knows what it have to do with it ???


EDIT: Yes the lifters are stock too ... in the near future I'm going to change cam, heads, valves, lifters etc... But till this time I want to get rid of this sound.

 

I dunno, that sounds weird to me...

 

The oil cap will keep some pressure in the system; might check to see if your PCV valve is working.

 

I replaced PCV Valve ... (this ticking/knocking sound starts to take place after rebuilding engine to 383 [after 200miles of breaking in], the PCV was replaced then) ... PCV Valve is rattling when shaken so by the information I have it is good ...

 

Hey, I've found a video of the sound my engine is making ...

Maybe it's not exactly knocking/ticking .. but I dont know how to describe this sound in english ..

So on the video I rev engine a little and the sound is still there, but then I rev it higher and it disappeared for few seconds ... and then I'm taking off the oil cap and it stops for as longs as the cap is off ... and when I place it back .. the sound returns after less than minute ...

I would be grateful for every advise!! Maybe it is some detail, and I dont have to buy new lifters or something like that ...

http://www.republika.azhrael.pl/camaro/LT1383_noise.wmv

 

Kind of hard to tell the sound from the video, but can you feel any air puffing out of the valve cover when you take the cap off? Have you checked to see if it is the PCV valve that is making the rattling/ticking sound? Put your hand on it and see if you can feel it doing anything.

 

When the oil cap is off, there is no air puffing out, and no sucking air in ...
only at the time when I'm opening the cap there is a sucking air sound ... and the sound disappear ...

I have taken the PCV Valve off, and shaken it ... there is a rattling sound coming from it .. now is the middle of the night in Poland, so tomorrow I will check if it is doing anything while engine is running ...

Thx for reply ... could it be some vacuum leak ??