C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Tapping noise

Thread Tools
 
Search this Thread
 
Old Sep 12, 2014 | 10:00 AM
  #1  
1975RedRay's Avatar
1975RedRay
Thread Starter
Cruising
 
Joined: Jul 2014
Posts: 12
Likes: 0
Default Tapping noise

So when I start up first thing in the morning (no matter if its cold or hot out) I am getting a tapping noise that changes with RPM's. When the car gets warmed up, the noise goes away. If the car sits and cools down, it happens again at startup.

The noise goes away after a few minutes. And you can beat on it and it won't make the noise.

It basically sounds like someone taking a bolt and tapping an exhaust pipe. Ive checked the exhaust...no clearance issues or anything loose.

I have a warmed over 350, with a cam, Weiand intake, Edelbrock carb, 3 inch exhaust no cats, full MSD setup.

Any thoughts or advice would be greatly appreciated.
Reply
Old Sep 12, 2014 | 11:46 AM
  #2  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,689
Likes: 2,571
Default

have you checked with a piece of rubber hose held near your ear and the other end near the valve covers if the noise is a loose rocker arm?
Reply
Old Sep 12, 2014 | 11:53 AM
  #3  
1975RedRay's Avatar
1975RedRay
Thread Starter
Cruising
 
Joined: Jul 2014
Posts: 12
Likes: 0
Default

Originally Posted by MelWff
have you checked with a piece of rubber hose held near your ear and the other end near the valve covers if the noise is a loose rocker arm?
I have not, but wouldn't the noise be present at all times if it was a loose rocker arm?
Reply
Old Sep 12, 2014 | 12:22 PM
  #4  
gerry72's Avatar
gerry72
Safety Car
20 Year Member
 
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Default

Exhaust leak.
Reply
Old Sep 12, 2014 | 12:29 PM
  #5  
1975RedRay's Avatar
1975RedRay
Thread Starter
Cruising
 
Joined: Jul 2014
Posts: 12
Likes: 0
Default

Originally Posted by gerry72
Exhaust leak.
Thank You for the reply, but again, if there was an exhaust leak wouldn't that sound be present at all times? My exhaust is a fully welded stainless system.
Reply
Old Sep 12, 2014 | 12:43 PM
  #6  
gjohnson's Avatar
gjohnson
Drifting
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2008
Posts: 1,808
Likes: 439
From: Denver CO
Default

My guess would be rocker or the pressed in rocker stud that has come loose causing the rocker to become loose.Cold, the oil lube has drained off enough to make the tapping sound until oil gets pumped backed up to quiet it down.
Reply
Old Sep 12, 2014 | 01:18 PM
  #7  
gerry72's Avatar
gerry72
Safety Car
20 Year Member
 
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Default

Originally Posted by 1975RedRay
Thank You for the reply, but again, if there was an exhaust leak wouldn't that sound be present at all times? My exhaust is a fully welded stainless system.
The symptoms you describe are very classic for a small exhaust leak. Once the system heats up and expands, it seals the leak. Nut and bolt the system while it's cold. The leak is at the manifold-to-head interface or the manifold-to-pipe interface. And by manifold, that means either iron manifolds or headers. I'm not talking a major leak but a tiny one.
Reply
Old Sep 12, 2014 | 01:24 PM
  #8  
Tin_Can_Terminator's Avatar
Tin_Can_Terminator
Advanced
 
Joined: Jan 2013
Posts: 65
Likes: 0
From: Kennesaw Georgia
Default

Sounds like a sticky lifter. My truck used to do the same thing. Once the engine warmed up it went away. Hydraulic lifter was sticky. I put in a quart of tranny fluid to clean the system and it helped stop it.

TCT
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-1

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-2

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-3

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-4

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-5

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-6

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-7

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-8

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-9

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
Old Sep 12, 2014 | 01:29 PM
  #9  
1975RedRay's Avatar
1975RedRay
Thread Starter
Cruising
 
Joined: Jul 2014
Posts: 12
Likes: 0
Default

Originally Posted by gerry72
The symptoms you describe are very classic for a small exhaust leak. Once the system heats up and expands, it seals the leak. Nut and bolt the system while it's cold. The leak is at the manifold-to-head interface or the manifold-to-pipe interface. And by manifold, that means either iron manifolds or headers. I'm not talking a major leak but a tiny one.
I could se this being the case on a nut and bolt/clamp system, but I have a front to back welded system. I did check the exhaust, which seems fine.
Reply
Old Sep 12, 2014 | 01:32 PM
  #10  
1975RedRay's Avatar
1975RedRay
Thread Starter
Cruising
 
Joined: Jul 2014
Posts: 12
Likes: 0
Default

Originally Posted by gjohnson
My guess would be rocker or the pressed in rocker stud that has come loose causing the rocker to become loose.Cold, the oil lube has drained off enough to make the tapping sound until oil gets pumped backed up to quiet it down.
That's what I have been seeing in some older posts. I think I am going to pull the valve covers off (haven't been off in about 10 yrs.) Will check the lifters and studs.

Was also thinking maybe a sticking fuel pump rod where it could be slapping? Seen that in other small block Chevrolets.....

Thanks again for the replies.
Reply
Old Sep 12, 2014 | 01:47 PM
  #11  
Easy Mike's Avatar
Easy Mike
Team Owner
Supporting Lifetime
20 Year Member
 
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Default

Originally Posted by Tin_Can_Terminator
...Sounds like a sticky lifter...
TCT
That gets my vote.
Reply

Get notified of new replies

To Tapping noise





All times are GMT -4. The time now is 01:26 AM.

story-0
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-1
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-2
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-3
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-4
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-5
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-6
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-7
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-8
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-9
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE