Generation IV Internal Engine 2005-2014 LS2 | LS3 | LS7 | L92 | LS9

L96 cam dowel failure

Thread Tools
 
Search this Thread
 
Old Sep 28, 2022 | 09:38 AM
  #1  
NastyNate65's Avatar
Thread Starter
Launching!
 
Joined: Mar 2008
Posts: 274
Likes: 7
From: Omaha, NE
Default L96 cam dowel failure

I just bought a 2016 Silverado 2500 with a 6.0 L96 VVT engine. I bought it cheap and non running knowing that it may need a new engine, but I wanted to see if I could fix this one first. Did compression tests on 3 different cylinders and got less than 20psi on each. Rockers still moved like they should, so I removed the timing cover, pulled the cam sprocket off and found the smoking gun....the camshaft dowel sheared off and the sprocket spun about 1/3 of a turn. Obviously these are interference engines so next step is to pull the heads and see what the damage is. Crossing my fingers that the cylinders are OK and I can just throw a set of heads and a VVT cam delete kit into this thing and be on my way. What is the simplest/cheapest way to tune these trucks if I delete VVT and just use a stock or mild towing cam?


Reply
Old Sep 28, 2022 | 09:56 AM
  #2  
Ls7colorado's Avatar
TECH Addict
20 Year Member
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Jul 2005
Posts: 2,119
Likes: 610
From: Henderson, TN
Default

Why would you want to delete the VVT?
I wouldn't be surprised if you find a dropped valve when you open the engine up, defiantly wouldn't be the first one ive seen.
Reply
Old Sep 28, 2022 | 11:29 AM
  #3  
NastyNate65's Avatar
Thread Starter
Launching!
 
Joined: Mar 2008
Posts: 274
Likes: 7
From: Omaha, NE
Default

I can delete VVT and tune it for more HP and better MPG and reliability. If this was a normal, non VVT 3 bolt cam, the sprocket could not have spun even if the cam dowel somehow broke. With this 1 bolt VVT cam it allowed the sprocket to spin and likely was the cause of the broken dowel in the first place since it is just one large bolt in the center of the cam. The latter is just my opinion, but this truck has high miles and I would like to replace the lifters while I am in here and may as well replace the cam and do a tune. I am not going to be surprised if there are some damaged pistons and valves, but we will see...
Reply
Old Aug 3, 2024 | 01:52 AM
  #4  
Mikef0821's Avatar
Registered User
 
Joined: Aug 2024
Posts: 1
Likes: 0
Default

Did you ever find out if there was valve damage done to the engine? I have a 2015 gmc with 6.0 in it. Was at idle and just shut off. No engine turns over like there is no compression. The engine was running smooth with no signs of anything wrong. Not even a check engine light.
Reply
Old Aug 3, 2024 | 09:22 AM
  #5  
G Atsma's Avatar
TECH Senior Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Default

OP hasn't been around for over a year.
Reply
Old Aug 4, 2024 | 10:08 AM
  #6  
grinder11's Avatar
TECH Junkie
20 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Sep 2004
Posts: 3,212
Likes: 1,612
From: Michigan & Florida
Default

@NastyNate65 Hey, guy-Did you find a solution/carnage/whatever???! I hate dead threads where OPs leave us hanging. If you're still above ground and receive the tag, please respond......

Last edited by grinder11; Aug 4, 2024 at 10:16 AM.
Reply
Old Aug 4, 2024 | 10:45 AM
  #7  
NastyNate65's Avatar
Thread Starter
Launching!
 
Joined: Mar 2008
Posts: 274
Likes: 7
From: Omaha, NE
Default

Hey there. This engine ended up having 3 cam bearings spun and welded to the cam. I pulled the engine and rebuilt it. The block wasn't damaged by the spun cam bearings. I had a machine shop clean the block and install new cam bearings, as well as polish/machine the crankshaft. There was barely a scuff on a few pistons from valves touching. I replaced all 8 pistons and re used the cylinder heads. Put everything together and it ran great! I drove it 1000 miles and sold it.
Reply
Old Aug 4, 2024 | 10:46 AM
  #8  
NastyNate65's Avatar
Thread Starter
Launching!
 
Joined: Mar 2008
Posts: 274
Likes: 7
From: Omaha, NE
Default

Originally Posted by Mikef0821
Did you ever find out if there was valve damage done to the engine? I have a 2015 gmc with 6.0 in it. Was at idle and just shut off. No engine turns over like there is no compression. The engine was running smooth with no signs of anything wrong. Not even a check engine light.
I would not be surprised if your cam dowel broke. Doesn't take too long to remove the timing cover and have a look.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Aug 4, 2024 | 10:56 AM
  #9  
NastyNate65's Avatar
Thread Starter
Launching!
 
Joined: Mar 2008
Posts: 274
Likes: 7
From: Omaha, NE
Default


Cam bearing welded to camshaft

I cut the cam bearing off the camshaft with a dremel






You can see where the valves kissed the pistons


Reply
Old Aug 4, 2024 | 11:03 AM
  #10  
NastyNate65's Avatar
Thread Starter
Launching!
 
Joined: Mar 2008
Posts: 274
Likes: 7
From: Omaha, NE
Default











I put the truck to work immediately
This was my first complete engine rebuild. Everything went according to plan, although it took longer than I anticipated. Mostly due to waiting on the machine shop. But those guys are always busy so it is what it is.
Reply




All times are GMT -5. The time now is 02:56 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE