Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Sponsored by:
Sponsored by: CARiD

Tapping Under Valve Cover

Thread Tools
 
Search this Thread
 
Old Jan 20, 2003 | 11:53 AM
  #1  
Squeeks83's Avatar
Thread Starter
Senior Member
 
Joined: May 2002
Posts: 973
Likes: 0
From: Avondale, AZ, used to be seattle, washington
Car: 1978 Chevrolet C10
Engine: 350
Transmission: Turbo 350
Tapping Under Valve Cover

well i have had a tapping noise for the life of my engine which just turned over 1k. it has always had a tapping in the passengerside valve cover. i think that the lash was never set properly on a rocker or something of that sort, so i was wondering if anyone could dig out some TQ numbers i am soposted to TQ the nuts to, and what degrees for the feeler gauges. thanks for any info.
Reply
Old Jan 20, 2003 | 12:00 PM
  #2  
87WS6's Avatar
Supreme Member
iTrader: (1)
 
Joined: Sep 2002
Posts: 2,565
Likes: 10
From: Texas
Car: 1992 Formula Firebird
Engine: 305CID (LB9)
Transmission: World Class T5
Axle/Gears: 10-bolt, 4.10 gears
If it is a rocker arm I can't tell you the presise torque amount. What I can tell you is that most people do it by ear. That I know of.

Open the valve cover and reinstall the gasket. (So oil doesn't go all over the place to much.) While the car is running find the offending rocker arm and tighten it down until you can not hear it anymore. Then give it one more quarter turn to lock it down.

This proceedure was given to me when I had this same problem.
Although on my car this turned out to not be the problem. It turned out to be a lifter. Hope this helps.
Reply
Old Jan 20, 2003 | 02:23 PM
  #3  
bad84z's Avatar
Senior Member
 
Joined: Sep 2002
Posts: 634
Likes: 0
From: Fort Meade MD
Car: 84 Z28
Engine: 355
Transmission: 700R4 with corvette servo
I had the same sound, only it turned out that my header bolts were loose and I blew a small hole in the header gasket. Replaced the gasket and tightned the headers down, now no more noise.
Reply
Old Jan 21, 2003 | 08:18 AM
  #4  
Vader's Avatar
Moderator
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Jan 2000
Posts: 19,651
Likes: 309
Squeeks,

The procedure all depends on which engine you have.

Pontiac V-8 engines used a torque specification and allowed the lifters to compensate for valve lash. Chevrolet V-8 engines use a "turns after zero lash" setting instead of a torque specification. You need to get the engine to operating temperature, remove the rocker cover, restart the engine, back off the rocker adjusting nut until you get obvious lash (tapping), then tighten the nut slowly until the lash is gone. Tighten an additional 1/4-1/2 turn beyond that point, and it's all set.
Reply
Old Jan 21, 2003 | 06:47 PM
  #5  
89WS-6's Avatar
Member
 
Joined: Dec 2001
Posts: 439
Likes: 0
From: Houston, Tx.
Another way I was taught to do this, is when a valve is closed, back off the rocker arm nut until there is clearence between its tip and the valve stem, start turning the pushrod with your hand, while tightening the nut, then as soon as the pushrod hesitates by touching the rocker arm, tighten the rocker nut 3/4 of a turn more, and your set, then turn the engine over and do the other 8. Hope that makes sense.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Hotrodboba400
Firebirds for Sale
3
Dec 10, 2019 07:07 PM
db057
TBI
14
Apr 28, 2019 07:45 AM
Nick McCardle
Firebirds for Sale
1
Sep 10, 2015 08:36 PM
Hotrodboba400
Firebirds for Sale
0
Sep 2, 2015 07:28 PM




All times are GMT -5. The time now is 03:03 AM.