Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

knock and scrape

Thread Tools
 
Search this Thread
 
Old 10-11-2007, 08:32 AM
  #1  
Teching In
Thread Starter
 
CTC B4Z's Avatar
 
Join Date: Oct 2007
Location: NWI
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts

Default knock and scrape

Hello all. Longtime gen 1 guy here, years on IrocZone and TGO, first time dealing with an LSx...


Anyway, my buddy picked up a 1998 T/A awhile back and we've been toying with it for some time now. Recently it just got really really cold out. Last night we were cruising as usual, everythings fine. I guess this morning on his way to school, he starts to hear a knock and scrape. He called and I thought it would just be the typical LS1 piston slap since it is cold out, but he said the engine was fully warmed.

He says it doesnt happen all the time though and it does kind of drop oil pressure and vary in RPM's. The engine does has about 112k on it, we ofcourse dont want to think about rod knock or oil pump failure, but what do you guys suggest?
Old 10-11-2007, 08:41 AM
  #2  
TECH Senior Member
 
PREDATOR-Z's Avatar
 
Join Date: Mar 2004
Location: BFE
Posts: 14,620
Likes: 0
Received 16 Likes on 16 Posts

Default

Sounds like rod bearings, not good and very common on 98s
Old 10-11-2007, 08:45 AM
  #3  
TECH Fanatic
iTrader: (17)
 
john563's Avatar
 
Join Date: Sep 2006
Location: dayton ohio
Posts: 1,638
Likes: 0
Received 0 Likes on 0 Posts

Default

I have a 98,and just like pred said its common on 98's. I replaced my rod bolts with Katechs and clevite bearings,just in case
Old 10-11-2007, 08:47 AM
  #4  
Teching In
Thread Starter
 
CTC B4Z's Avatar
 
Join Date: Oct 2007
Location: NWI
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts

Default

So, if it hasnt chwed up the crank and such already, it is possible to just replace the bearings and have no machine work done? or is it a must to also have the crank turned down and oversized bearings put in place? For the rod bolts, those will need to be pressed in/out correct?


thanks for the quick replies guys
Old 10-11-2007, 08:50 AM
  #5  
TECH Senior Member
 
PREDATOR-Z's Avatar
 
Join Date: Mar 2004
Location: BFE
Posts: 14,620
Likes: 0
Received 16 Likes on 16 Posts

Default

It would require rebuilt of shortblock, all else is a band aid
Old 10-11-2007, 08:54 AM
  #6  
Teching In
Thread Starter
 
CTC B4Z's Avatar
 
Join Date: Oct 2007
Location: NWI
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts

Default

Why is it common with the 98's? I heard the first batch of LS1's, like 98-00 were built tighter and oiling problems and such.
Old 10-11-2007, 09:25 AM
  #7  
TECH Fanatic
iTrader: (17)
 
john563's Avatar
 
Join Date: Sep 2006
Location: dayton ohio
Posts: 1,638
Likes: 0
Received 0 Likes on 0 Posts

Default

I did not have any knock or scrape. I added the katechs to avoid this. If I did have a knock or scrape as you are describing I would have done a rebuild
Old 10-11-2007, 09:48 AM
  #8  
Teching In
Thread Starter
 
CTC B4Z's Avatar
 
Join Date: Oct 2007
Location: NWI
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts

Default

What about the possibilities of other things that I have read up on here such as pushrod issues and loose rocker? Should we check those first before we yank the motor out?
Old 10-11-2007, 09:55 AM
  #9  
TECH Regular
 
pdsq98gt's Avatar
 
Join Date: Sep 2007
Location: Kansas City, MO
Posts: 435
Likes: 0
Received 2 Likes on 2 Posts

Default

Typically a valvetrain noise is at half the speed of the engine and a piston/rod problem is 2x faster than a valvetrain noise. If it's a slow tick it's valvetrain. If it's fast, bottom end.
Old 10-11-2007, 09:59 AM
  #10  
Teching In
Thread Starter
 
CTC B4Z's Avatar
 
Join Date: Oct 2007
Location: NWI
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts

Default

Anybody have a complete bottom end rebuild list?

better yet, any of the sponsers sell shortblocks? Links?

looks like this is golden.. ..

http://www.sdparts.com/product/SDLS6...kAssembly.aspx

Now, anybody sell a complete gasket kit?

Last edited by CTC B4Z; 10-11-2007 at 10:40 AM.




All times are GMT -5. The time now is 08:18 PM.