S2000 Under The Hood S2000 Technical and Mechanical discussions.

Tapping and knock sound

Thread Tools
 
Old 06-16-2013, 08:25 PM
  #1  
Registered User
Thread Starter
 
alir's Avatar
 
Join Date: Sep 2012
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default Tapping and knock sound

So I had the infamous TCT problem, swapped it with a new one (I know should have got a billman) that fixed my warm engine sound but then I had another sound that would get louder when revving passed 2500RPM. Mind you the car was dead silent below that and idling.

I searched around and figured it was a valve adjustment, went ahead and did one (my first time, but I triple checked clearance) and now it sounds like so:

[media]http://www.youtube.com/watch?v=0C6crNaU64I[/media]

It sounds much worse from a cold start but this is me warming it up before resetting the ECU (after valve adjustment). It also died after I gave it a little throttle.

What does it sound like? I've already come to terms with the fact I might need a new engine but I figured maybe I can salvage this one or maybe I just did my TCT swap/valve adjustment wrong.

Thanks ahead.
Old 06-16-2013, 09:03 PM
  #2  
Community Organizer
Community Organizer
 
s2000Junky's Avatar
 
Join Date: Jun 2007
Posts: 31,059
Received 554 Likes on 506 Posts
Default

Sounds like the top of a piston hitting a valve. If so, its more then likely related to your adjustment. Almost positive it is if you noticed that sound only right after adjustment. Run a scope/cam down into the spark plug hole to look for damage/contact marks on top off piston in one of the cylinders for confirmation.
Old 06-16-2013, 10:10 PM
  #3  
Registered User
Thread Starter
 
alir's Avatar
 
Join Date: Sep 2012
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default

There was a similar clatter before the adjustment but only above 2500 RPM. It only started a day before I swapped the TCT which I had unknowingly been driving on for a while.

This video is of the car idling at around 1000 RPM. When I give it throttle for a second at around 0:18 you can hear the clatter increase in noise/speed with RPM before dying.

I'll give what you said a shot, thanks for the response.
Old 06-17-2013, 01:42 AM
  #4  
Registered User
 
My_01_s2k's Avatar
 
Join Date: Dec 2010
Posts: 10
Likes: 0
Received 0 Likes on 0 Posts
Default

sounds so painful...good luck my friend
Old 06-17-2013, 04:46 AM
  #5  

 
MM3Kwolik's Avatar
 
Join Date: Jun 2010
Location: McKinney, TX
Posts: 5,539
Likes: 0
Received 6 Likes on 6 Posts
Default

Have you checked your retainers at all? Maybe you did an adjustment on a valve that has almost pulled itself through the retainer which is causing piston/valve contact, especially after a valve adjustment. Chances are your tappets are contacting the retainer rather than the top of the valve stem. Pull the VC and post up pics of all of your intake retainers. If you can, pull the cams so you can swing the rockers away to get good pictures/view of the valve stems/retainers.
Old 06-17-2013, 12:47 PM
  #6  
Registered User

 
miloking's Avatar
 
Join Date: Nov 2011
Posts: 435
Received 16 Likes on 13 Posts
Default

I would NOT start this car again until you find what this is!!!!! I think you got lucky so far... take valve cover off like others said and find out whats going on.
Old 06-17-2013, 01:33 PM
  #7  
Registered User
Thread Starter
 
alir's Avatar
 
Join Date: Sep 2012
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by jordanksartell
Have you checked your retainers at all? Maybe you did an adjustment on a valve that has almost pulled itself through the retainer which is causing piston/valve contact, especially after a valve adjustment. Chances are your tappets are contacting the retainer rather than the top of the valve stem. Pull the VC and post up pics of all of your intake retainers. If you can, pull the cams so you can swing the rockers away to get good pictures/view of the valve stems/retainers.
Everything inside looked fine, as-in nothing seemed broken or damaged but I've no experience with engines so I might have overlooked something. I'll try to get some pics up later today.

Originally Posted by miloking
I would NOT start this car again until you find what this is!!!!! I think you got lucky so far... take valve cover off like others said and find out whats going on.
I figured as much, I haven't driven it since. Not taking any chances in case I can save it.
Old 06-17-2013, 03:00 PM
  #8  
Registered User

 
AZ-S2000's Avatar
 
Join Date: Dec 2011
Posts: 1,186
Likes: 0
Received 2 Likes on 2 Posts
Default

Did it stall out after revving it?
Old 06-17-2013, 03:27 PM
  #9  
Registered User
Thread Starter
 
alir's Avatar
 
Join Date: Sep 2012
Posts: 44
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by AZ-S2000
Did it stall out after revving it?
In the video yes, but that's never been a problem before this noise started.
Old 06-18-2013, 03:21 AM
  #10  
Registered User
 
Floppy's Avatar
 
Join Date: Apr 2008
Location: Northamptonshire
Posts: 3,748
Likes: 0
Received 3 Likes on 2 Posts
Default

Definitely sounds like valve slap to me. Running it again risks breaking the valve stem and the valve dropping into the cylinder head so as already said, do not start it again until you've looked at the problem properly.

Taking the rocker cover off wont show you anything visually I wouldn't have thought. My other concern would be if you sort the problem out and it is a retainer there is no way of telling whether the valve stem will have any fractures in it and if it does, again it's only a matter of time until it drops off, probably under high revs that'll cause your engine to go boom.

I hope you get it sorted


Quick Reply: Tapping and knock sound



All times are GMT -8. The time now is 09:41 PM.