Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

Name this noise (engine tick)

 
Old 01-25-2011, 11:54 PM
  #1  
BC
Addict
Rennlist Member
Thread Starter
 
Join Date: Dec 2001
Posts: 24,527
Default Name this noise (engine tick)



Anyone have any ideas?
BC is offline  
Old 01-25-2011, 11:56 PM
  #2  
IcemanG17
Super User
 
IcemanG17's Avatar
 
Join Date: Sep 2004
Location: Stockton, CA
Posts: 15,989
Default

does it change with RPM? If it does...its bad news....since it sounds like rod knock to me....... When the 1st engine in the 928 Estate died...it sounded alot like that
IcemanG17 is offline  
Old 01-25-2011, 11:57 PM
  #3  
Hilton
Super User
 
Hilton's Avatar
 
Join Date: Jun 2006
Location: ɹəpun uʍop 'ʎəupʎs
Posts: 6,097
Default

Is there a belt on the airpump? (likely on a mechanical fan clutch car like this).

Remove it for a quick test. Switch to shorter belt that avoids air pump if it is the problem.
Hilton is offline  
Old 01-26-2011, 12:11 AM
  #4  
blown 87
Rest in Peace
Rennlist Member
 
blown 87's Avatar
 
Join Date: May 2006
Location: Bird lover in Sharpsburg
Posts: 9,903
Default

Rod knock, fan hitting the shrowd, broken flex plate, lots of things can cause a sound like that, but it sounds expensive and a lot like a rod from here.
blown 87 is offline  
Old 01-26-2011, 12:12 AM
  #5  
BC
Addict
Rennlist Member
Thread Starter
 
Join Date: Dec 2001
Posts: 24,527
Default

Originally Posted by IcemanG17 View Post
does it change with RPM? If it does...its bad news....since it sounds like rod knock to me....... When the 1st engine in the 928 Estate died...it sounded alot like that
That was my first thought. BUT... the reason I do not believe that it is rodknock is because it is at a faster rate than the rodknock I have heard before, and its clearly coming from the top of the engine. But of course I could be wrong. Infact many times I am. But I get some right.

Rod knock would be at the same speed as piston slap, which sounds like this:

BC is offline  
Old 01-26-2011, 12:15 AM
  #6  
BC
Addict
Rennlist Member
Thread Starter
 
Join Date: Dec 2001
Posts: 24,527
Default

Originally Posted by blown 87 View Post
Rod knock, fan hitting the shrowd, broken flex plate, lots of things can cause a sound like that, but it sounds expensive and a lot like a rod from here.

Okay. The noise is not the fan. Its a 5spd, so it doesn't have a flex plate.

It may be, and if it is, I'm in trouble. But the speed doesn't seem like it. Its almost like a loud injector, but its not that I guess. What about a timing chain problem?
BC is offline  
Old 01-26-2011, 12:20 AM
  #7  
neilh
User
 
neilh's Avatar
 
Join Date: Mar 2004
Location: Southport, NC
Posts: 1,601
Default

Originally Posted by BC View Post
Okay. The noise is not the fan. Its a 5spd, so it doesn't have a flex plate.

It may be, and if it is, I'm in trouble. But the speed doesn't seem like it. Its almost like a loud injector, but its not that I guess. What about a timing chain problem?
Timing chain broken link flailing around and hitting the underside of the cam cover?
neilh is offline  
Old 01-26-2011, 12:44 AM
  #8  
blown 87
Rest in Peace
Rennlist Member
 
blown 87's Avatar
 
Join Date: May 2006
Location: Bird lover in Sharpsburg
Posts: 9,903
Default

What is the history of the car?
Any metal flake in the oil?
The problems when trying to figure out a issue like this is the fact you need to run it to track the noise down, and you do not know how far away from a total failure you are.

I would heed the advice from Mr Merlin and check the cam gears and hubs before running it again.
But I have heard 928 engines with broken hubs that only missed, and did not make any noise.
blown 87 is offline  
Old 01-26-2011, 01:11 AM
  #9  
BC
Addict
Rennlist Member
Thread Starter
 
Join Date: Dec 2001
Posts: 24,527
Default

I think it sat for more than 3 years. There was supposedly some top end work done at some point. Oil is clean from what I can tell.
BC is offline  
Old 01-26-2011, 10:37 AM
  #10  
WallyP

Rennlist Member
Rennlist Site Sponsor

 
Join Date: Jun 2001
Location: Acworth, GA
Posts: 6,469
Default

While it is unlikely, given that you said that the noise sounded as if it was coming from the top of the engine, I had one that sounded like that due to a broken strap on the pressure plate. The strap pivoted out and hit the ribs inside the bellhousing. A quick look inside the clutch housing will take care of that possibility...
WallyP is offline  
Old 01-26-2011, 10:58 AM
  #11  
SteveG
Addict
Rennlist Member
 
SteveG's Avatar
 
Join Date: Jul 2001
Location: New York
Posts: 5,931
Default

Stethoscope or hose used as same might locate the spot.
SteveG is offline  
Old 01-26-2011, 11:32 AM
  #12  
SQLGuy
User
 
SQLGuy's Avatar
 
Join Date: Mar 2010
Location: Colorado Springs, CO USA
Posts: 1,297
Default

If it sat for three years, maybe it's just multiple collapsed cam followers?
SQLGuy is offline  
Old 01-26-2011, 12:48 PM
  #13  
BC
Addict
Rennlist Member
Thread Starter
 
Join Date: Dec 2001
Posts: 24,527
Default

I was thinking of the stethoscope idea. Where would I get one of those?
BC is offline  
Old 01-26-2011, 12:49 PM
  #14  
BC
Addict
Rennlist Member
Thread Starter
 
Join Date: Dec 2001
Posts: 24,527
Default

Can you conceivably run the car at idle with the cam covers off?
BC is offline  
Old 01-26-2011, 12:53 PM
  #15  
neilh
User
 
neilh's Avatar
 
Join Date: Mar 2004
Location: Southport, NC
Posts: 1,601
Default

Originally Posted by BC View Post
I was thinking of the stethoscope idea. Where would I get one of those?
http://www.harborfreight.com/catalog...&q=stethoscope
neilh is offline  

Thread Tools
Search this Thread

Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: