Engine tick/clatter
Thread Starter
Race Director
Joined: Sep 2001
Posts: 13,292
Likes: 0
From: Hockessin Delaware
Engine tick/clatter
After digging the vette out now that the weather is clearing, I was surprised to hear some what I thought was valvetrain clatter when driving the other day. I've narrowed it down to only 2500-3000 rpms, with a quieting (and maybe disappearing around 2800 for a split second).
Any ideas what it could be? I'm running the G5X-3 114 with comp 921s. From what I've read if it was a valvespring, it would be a more prevalent noise than what I'm hearing and it would be obvious. Also seems to me that if it was valvetrain, it wouldn't go away at higher rpms (or not be there at lower rpms either), but I'm not sure about that.
No codes at all on the DIC.
Thanks in advance.
Any ideas what it could be? I'm running the G5X-3 114 with comp 921s. From what I've read if it was a valvespring, it would be a more prevalent noise than what I'm hearing and it would be obvious. Also seems to me that if it was valvetrain, it wouldn't go away at higher rpms (or not be there at lower rpms either), but I'm not sure about that.
No codes at all on the DIC.
Thanks in advance.
Thread Starter
Race Director
Joined: Sep 2001
Posts: 13,292
Likes: 0
From: Hockessin Delaware
Thanks. That's first on my list, but after some reading here, I got the impression a broken valve spring would make a lot more noise -- this is more than normal big cam valvetrain clatter - but a lot less than "something is seriously broken" noise. 
Drifting
Joined: Feb 2007
Posts: 1,446
Likes: 0
From: Cranford NJ
The sowing machine sound is pretty common after upgrading the camshaft.
Usually a result of the following:
-increased ramp rates on the cam
-increased lift
-thinner walled tubing on the exhaust(AKA the headers)
Have a look to make sure, better safe than sorry.
Max
Usually a result of the following:
-increased ramp rates on the cam
-increased lift
-thinner walled tubing on the exhaust(AKA the headers)
Have a look to make sure, better safe than sorry.
Max
8th Gear
Joined: Apr 2007
Posts: 8
Likes: 0
Hope this isn't the case, but I had "similar" issue where previous owner installed cam and solid pushrods, but didn't match springs and slowly but surely cam lobe got worn by "floating" lifters.....resulting in pulling engine, new cam and full lifter, pushrod and spring replacement....
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
You make it sound like these are new noises after getting it out of winter storage. Maybe since you haven't heard it ran for a while, your ear was a little more "tuned" to noises you haven't heard before.
Thread Starter
Race Director
Joined: Sep 2001
Posts: 13,292
Likes: 0
From: Hockessin Delaware
Thanks everyone -- I've had the G5X-3 installed for going on 3 years now, never heard noises like this before. I'm accustomed to the sewing machine clatter - but this is a distinct tapping that comes in at 2500 rpms and goes away after 3000. Trying to figure out if the fact that it comes and goes makes it unlikely to be valvetrain - I'd think it would carry all the way through the rpm range if it was valvetrain, but that's just an uneducated guess. 
