shocktherapy
07-09-2009, 07:40 AM
I've been to several mechanics with this, but nobody knows what it is.
On a cold start, the engine sounds perfect for about a minute or two. Then, an irregular tapping begins and gets louder and louder until I give it an aggressive rev. It stops temporarily, then begins again. After warm up it is less noticeable, but still there.
I wonder if there is a valve or something that begins to open and close that is silent right at start up, but begins to operate as the engine warms up.
To me it sounds like I think a lifter would if it was not fully pumped up, but I have never heard a bad lifter, so I know diddly about it. It just seems to come from that part of the engine and sounds like a metal on metal tapping noise.
toobroketoretire
07-09-2009, 10:52 AM
It could be coming from a single rocker arm that is running slightly crooked with it's valve. The valve stem tip might be worn slightly crooked, or the rocker arm face might be worn slightly crooked as well. If you could pinpoint which rocker arm is causing it, you could remove it and inspect it for tip wear. It may not have been heat treated correctly.
buckshot42
07-10-2009, 07:52 AM
:goodpost: I would check your rockers as that is pretty easy to do, hopefully you find your issue there!
Todd157k
07-13-2009, 02:03 PM
+1 on checking those rockers. The needle bearings are known for coming out. You may find them in your oil pan.
Blackhorse Zo6
07-13-2009, 09:09 PM
I was reading some were about the lifter rattle & they said that the oil filter could be bad & I know for fact that my brother's 55 was 468 BB & he changed oil & filter lost oil pressure & he thought it was the pump so he changrd the pump & no help so he thought the pump he bough was bad so he changed it again no help so he called me & I ask him what has done he told me all he did was chaned the oil & filter ..So I said the problem is the filter .well it was the filter it was bad .Buy I 'm not saying thats your problem...........................:patriot:
zoomvettezoom
07-14-2009, 07:11 AM
+1 on checking those rockers. The needle bearings are known for coming out. You may find them in your oil pan.
This sounds like a nightmare!
freedomfighter
07-14-2009, 01:27 PM
I was reading some were about the lifter rattle & they said that the oil filter could be bad & I know for fact that my brother's 55 was 468 BB & he changed oil & filter lost oil pressure & he thought it was the pump so he changrd the pump & no help so he thought the pump he bough was bad so he changed it again no help so he called me & I ask him what has done he told me all he did was chaned the oil & filter ..So I said the problem is the filter .well it was the filter it was bad .Buy I 'm not saying thats your problem...........................:patriot:
Oil filter.....have not heard of that being the culprit for this issue before, but that is why I am not an expert!
DynamicTuningSolutions
07-14-2009, 01:32 PM
What is your oil pressure when it starts getting louder? That would be the first sign of issues if it drops suddenly.
dragonfire
07-15-2009, 07:46 AM
What is your oil pressure when it starts getting louder? That would be the first sign of issues if it drops suddenly.
I agree, this is the main thing to look for if a lifter is suspect #1