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

Professional Help Needed

Thread Tools
 
Search this Thread
 
Old Apr 27, 2013 | 05:33 PM
  #1  
1slowbusa's Avatar
Thread Starter
11 Second Club
iTrader: (8)
 
Joined: Jan 2011
Posts: 346
Likes: 1
From: Pen Argyl, PA
Default Professional Help Needed

Please do not bring in your opinions on this matter, I need answers with experience.

Last year I flycut my pistions and installed a G5X3 112lsa cam and AFR 205 62CC chamber heads. I have been fighting a knock sensor problems ever sense and as you probably read on another thread, I replaced everything more than once and there was no cure. So I decided to pull the engine apart and check everything. I have the intake and heads off. I checked the flycut depth (Seen below). What do you guys think. There is some differences in the cut depth in the pistons but will the small differences cause an unbalance in the engine as to where it would pick up false knock? The car ran great, it was just that I kept getting the knock sensor fault for the front. Thanks in advance.

Cylinder 1
Intake ~.132
Exhaust ~.079

Cylinder 3
Intake ~.079
Exhaust ~.075

Cylinder 5
Intake ~.084
Exhaust ~.083

Cylinder 7
Intake ~.088
Exhaust ~.094

Cylinder 2
Intake ~.081
Exhaust ~.088

Cylinder 4
Intake ~.087
Exhaust ~.092

Cylinder 6
Intake ~.090
Exhaust ~.077

Cylinder 8
Intake ~.078
Exhaust ~.072
Reply
Old Apr 28, 2013 | 12:36 PM
  #2  
1slowbusa's Avatar
Thread Starter
11 Second Club
iTrader: (8)
 
Joined: Jan 2011
Posts: 346
Likes: 1
From: Pen Argyl, PA
Default

Bump for today
Reply
Old Apr 29, 2013 | 07:55 PM
  #3  
1slowbusa's Avatar
Thread Starter
11 Second Club
iTrader: (8)
 
Joined: Jan 2011
Posts: 346
Likes: 1
From: Pen Argyl, PA
Default

Bump for today.
Reply
Old Apr 29, 2013 | 08:20 PM
  #4  
JakeFusion's Avatar
Super Hulk Smash
20 Year Member
Liked
Loved
Community Favorite
iTrader: (7)
 
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
Default

The tolerances on a stock motor are all over the place. That's not causing the problem. If you actually look at the A/F ratio on each cylinder, you're see they are all different too (flycut or not).

Throw race gas in there. See if you're getting actual KR or false KR. If it's still knocking with 100 octane, then it's a false knock. You can tune some of that sensitivity out. If it's from the front knock sensors, it might be the timing chain (double roller?).
Reply
Old Apr 29, 2013 | 09:54 PM
  #5  
1slowbusa's Avatar
Thread Starter
11 Second Club
iTrader: (8)
 
Joined: Jan 2011
Posts: 346
Likes: 1
From: Pen Argyl, PA
Default

Originally Posted by JakeFusion™
The tolerances on a stock motor are all over the place. That's not causing the problem. If you actually look at the A/F ratio on each cylinder, you're see they are all different too (flycut or not).

Throw race gas in there. See if you're getting actual KR or false KR. If it's still knocking with 100 octane, then it's a false knock. You can tune some of that sensitivity out. If it's from the front knock sensors, it might be the timing chain (double roller?).
thanks, I am running a double roller timing chain. I thought about that but I haven't taken the timing cover chain off to check. How might that be causing the problem? Is there anything certain I should look for?
Reply
Old Apr 29, 2013 | 11:57 PM
  #6  
JakeFusion's Avatar
Super Hulk Smash
20 Year Member
Liked
Loved
Community Favorite
iTrader: (7)
 
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
Default

If you have any interference there it could be perceived as knock, even though the frequency would probably be wrong. Even if not, double-rollers are pretty damn noisy, but again, the frequency shouldn't be where the sensors are "looking." Still might be worth a look.
Reply
Old May 1, 2013 | 04:48 PM
  #7  
1slowbusa's Avatar
Thread Starter
11 Second Club
iTrader: (8)
 
Joined: Jan 2011
Posts: 346
Likes: 1
From: Pen Argyl, PA
Default

Thanks Jake fusion, I am going to try and take the balancer off and take the timing cover off this weekend and take a look.
Reply




All times are GMT -5. The time now is 05:15 PM.

story-0
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-1
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-2
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-3
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-4
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-5
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-6
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-7
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-8
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-9
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