Drop vavles, cam - Page 2 - Corvette Forum : DigitalCorvettes.com Corvette Forums
 
 
Go Back   Corvette Forum : DigitalCorvettes.com Corvette Forums > C6 Corvette Forums > C6 Corvette Z06
Register Forums Garage Garage Mark Forums Read Auto EscrowInsurance

Notices

C6 Corvette Z06
General | Technical | Performance | Aftermarket | Discussions

Shops/Tuners
Custom Image Corvettes
A&A Corvette
Corvette tuner

Interior
Corvette aftermarket products

Insurance

Parts & Products
Race Ramps
Edelbrock
ATI/Procharger
Corvetteguys.com
Melrose Motorsports
Parts Taxi
Airaid
Mid America Motorworks
Pfadt Racing
Madvette Motorsports
Hi-tech Custom Concepts
Corvette aftermarket products
Corvette Garage
Corvette Parts and Accessories
Corvette Car Care Products
Corvette HID
Mid America Motoroworks

Tracks/Schools
Bob Bondurant School of High Performance Driving
Corvette driving school

Wheels/Tires
Cray Wheels

Services
BADWERKS.com
Reply
 
Thread Tools
Old 12-22-2012, 05:47 AM   #16
ironhorse
DC Crew
 
ironhorse's Avatar
 
Posts: 338
Member #74885
Member since: Sep 2008
Location: S.Florida

Thanks: 2
Thanked 6 Times in 6 Posts
Quote:
Originally Posted by ArKay99 View Post
What Raid and Ivan said. Remember, the LS7 rocker ratio is 1.9:1, so the ramp is more severe. Couple that with a 7k red line and a bigger cam, the valve springs are going to take a beating. There were a lot of documented spring failures in the earlier LS7's...then sump issues...supposedly all fixed in 2009. If you are going to road race the car, I would suggest looking into improving the sump system.
Ther rocker ratio is 1.8 on LS7, there are documented dropped valves from 2006-up through 2011. Due in most part to bad or worn valve guides, or bad valve train geometry by some...Bad needle bearing end caps in LS7 rockers from jan 2007-late July 2007, bad batch...caused needle bearings to end up in oil pan.
ironhorse is online now   Reply w/quote Quick reply to this message
The Following User Says Thank You to ironhorse For This Useful Post:
ArKay99 (12-22-2012)
Sponsored Links
Advertisement
 
Old 12-22-2012, 08:14 AM   #17
ArKay99
 
ArKay99's Avatar
 
Posts: 9,872
Member #43955
Member since: Mar 2006
Location: Indian Rocks Beach, FL, USA

My Corvette(s)
1999 FRC - 2009 Z06

Thanks: 190
Thanked 256 Times in 177 Posts
Garage
Quote:
Originally Posted by ironhorse View Post
Ther rocker ratio is 1.8 on LS7, there are documented dropped valves from 2006-up through 2011. Due in most part to bad or worn valve guides, or bad valve train geometry by some...Bad needle bearing end caps in LS7 rockers from jan 2007-late July 2007, bad batch...caused needle bearings to end up in oil pan.
Oops, thanks for the correction! I meant 1.8:1, that one got by me. Over on the 'other' forum, I had read about some spring failures as I looked into LS7 issues before I bought my 09. It's been a while. I had also read about that batch problem.
ArKay99 is online now   Reply w/quote Quick reply to this message
Extreme taxation, excessive controls, oppressive government competition with business, frustrated minorities and forgotten Americans are not the products of free enterprise. They are the residue of centralized bureaucracy, of government by a self-anointed elite. - Ronald Reagan
Old 12-22-2012, 09:18 AM   #18
BJC99Hardtop
DC Crew
 
BJC99Hardtop's Avatar
 
Posts: 556
Member #16712
Member since: Aug 2004
Location: Pittsburgh, PA

My Corvette(s)
2006 Z06, 1999 FRC

Thanks: 25
Thanked 34 Times in 30 Posts
Quote:
Originally Posted by the machine View Post
I have posted this before but it deserves repeating...

It is critical with an LS7 to warm up the motor before beating it. The tollerances on this motor are very close and designed to only be correct when the engine is at opperating temps. Metal expands when it heats up and aluminum moves much more than cast iron.

I never rev higher than 3000 RPM until the engine oil reaches 100 degrees. Do not go by water temp as that is controlled by the thermostat to get hotter sooner.(the hotter water helps warm up the metal) The metal in the engine needs to soak the heat to expand into it's design specs. The metal temp is better represented by oil temp than water temp, and there is no metal temp guage.


I have been following this advice since the first time I read it a couple of years ago. The oil temp is always displayed on my DIC. It is interesting how long it takes for the oil to go from 75 degrees to 100 degrees. I usually wait for 150 degrees before 6K RPM shifts!

No problems so far, but I keep the warranty up just in case. At $400 per year bumper-to-bumper, that is cheap insurance.
BJC99Hardtop is online now   Reply w/quote Quick reply to this message
Old 12-22-2012, 09:28 AM   #19
ironhorse
DC Crew
 
ironhorse's Avatar
 
Posts: 338
Member #74885
Member since: Sep 2008
Location: S.Florida

Thanks: 2
Thanked 6 Times in 6 Posts
Quote:
Originally Posted by ArKay99 View Post
Oops, thanks for the correction! I meant 1.8:1, that one got by me. Over on the 'other' forum, I had read about some spring failures as I looked into LS7 issues before I bought my 09. It's been a while. I had also read about that batch problem.
Hey Bud, glad to help...
ironhorse is online now   Reply w/quote Quick reply to this message
Old 12-22-2012, 02:31 PM   #20
Mang
DC Crew
 
Mang's Avatar
 
Posts: 61
Member #72425
Member since: Apr 2008
Location: The Netherlands

My Corvette(s)
Black 2006 C6-Z06

Thanks: 1
Thanked 0 Times in 0 Posts
Last month a valve dropped from my buddy's 2006 Z06, A bone stock street car, with ony 37K miles. We removed the heads and found the cylinder sleeve cracked, most probaly another LS7 engine written off.
My Z06 was a only few cars later on the production line, with 35K miles also completly stock, both of our cars share the same defects which came along, cracked starter button, doorpads, clutch fluid, battery etc. To avoid valve drop problem with my Vette, I decided to replace the exhaust valves for the new Katech Ti/Mo exhaust valves. With the Molybdene steel stem they run excellent with bronze guides. I want to keep my original Ti intake valves but want to replace the guides. These all Ti guides doesn't run well with bronze guides, so I want to have the original Sintered steel guides. But they are not easy available, anyone has suggestions ?

Thanks in advance,
Regards,

Mang
Mang is offline   Reply w/quote Quick reply to this message
GM Chrome Sill plates, 2008+ style Carbon & leather console, US spec. red taillights, Smoothie Red Fuel Rail Covers & Chrome letter inserts, Stainless Steel interior parts, Corvette logo hood pad, Rear Parking distance control, Optima Red Top Battery, High polished Stainless Mesh grille. Akrapovic Titanium Evolution exhaust system.
Old 12-22-2012, 02:38 PM   #21
ironhorse
DC Crew
 
ironhorse's Avatar
 
Posts: 338
Member #74885
Member since: Sep 2008
Location: S.Florida

Thanks: 2
Thanked 6 Times in 6 Posts
Quote:
Originally Posted by Mang View Post
Last month a valve dropped from my buddy's Z06, A bone stock street car, with ony 37K miles. We removed the heads and found the cylinder sleeve cracked, most probaly another LS7 engine written off.
My Z06 is only a few VIN later produced, with 35K miles also completly stock, we share all the defects which came along with our Z06, cracked starter button, doorpads, clutch fluid, battery etc. To avoid valve drop problem with my Vette, I decided to replace the exhaust valves for the new Katech Ti/Mo exhaust valves. With the Molybdene steel stem they run excellent with bronze guides. I want to keep my original Ti intake valves but want to replace the guides. These all Ti guides doesn't run well with bronze guides, so I want to have the original Sintered steel guides. But they are not easy

available, anyone has suggestions ?

Thanks in advance,
Regards,

Mang



Check with Lingenfelter, I believe they have access to the original guides...See if you can speak with Graham Behan, cheif engineer at LPE...Also, if the Ti Valves are coated properly with the Molyb, then bronze guides will be fine...See bold on your post ...
ironhorse is online now   Reply w/quote Quick reply to this message
The Following User Says Thank You to ironhorse For This Useful Post:
Mang (12-22-2012)
Old 12-29-2012, 04:02 PM   #22
MEATHEAD1
 
MEATHEAD1's Avatar
 
Posts: 1,386
Member #48881
Member since: Aug 2006
Location: FT WORTH/DALLAS TX

My Corvette(s)
ZO6 07

Thanks: 3
Thanked 1 Time in 1 Post
Shop vrs HOME SHOP

I do not drive my vette much right now but looking at the shop doing the work vrs me right now the shop has me beat 2 yr 24 warranty, for 7500, cam head work port polish headers and a tune, doing the work I would save a little money but no warranty. Very hard not to let them do the work.
MEATHEAD1 is offline   Reply w/quote Quick reply to this message
YES YOU CAN DRIVE IT,,,,JUST MAKE THE FIRST PAYMENT.

I'M a Post Whore <------its official now.
Old 12-30-2012, 05:37 PM   #23
MEATHEAD1
 
MEATHEAD1's Avatar
 
Posts: 1,386
Member #48881
Member since: Aug 2006
Location: FT WORTH/DALLAS TX

My Corvette(s)
ZO6 07

Thanks: 3
Thanked 1 Time in 1 Post
Quote:
Originally Posted by mulinjohe View Post
you need to determine if your car is an early or late 07.
It really does not matter what year, from what I have been told and have seen at the shops, it would be in my best interested to do the job on the heads. The great upside is better flow and power. For a little more cash its worth it
MEATHEAD1 is offline   Reply w/quote Quick reply to this message
YES YOU CAN DRIVE IT,,,,JUST MAKE THE FIRST PAYMENT.

I'M a Post Whore <------its official now.
Old 12-30-2012, 11:40 PM   #24
ArKay99
 
ArKay99's Avatar
 
Posts: 9,872
Member #43955
Member since: Mar 2006
Location: Indian Rocks Beach, FL, USA

My Corvette(s)
1999 FRC - 2009 Z06

Thanks: 190
Thanked 256 Times in 177 Posts
Garage
Quote:
Originally Posted by Mang View Post
Last month a valve dropped from my buddy's 2006 Z06, A bone stock street car, with ony 37K miles. We removed the heads and found the cylinder sleeve cracked, most probaly another LS7 engine written off.
My Z06 was a only few cars later on the production line, with 35K miles also completly stock, both of our cars share the same defects which came along, cracked starter button, doorpads, clutch fluid, battery etc. To avoid valve drop problem with my Vette, I decided to replace the exhaust valves for the new Katech Ti/Mo exhaust valves. With the Molybdene steel stem they run excellent with bronze guides. I want to keep my original Ti intake valves but want to replace the guides. These all Ti guides doesn't run well with bronze guides, so I want to have the original Sintered steel guides. But they are not easy available, anyone has suggestions ?

Thanks in advance,
Regards,

Mang
My old LS1 sucked a washer into the number 7 hole, crushed the piston, gouged the head, and cracked the cylinder wall. When I contacted Lingenfelter to purchase my semi-long-block, they told me they could replace the sleeve, for about $400... wasn't worth it for an old LS1, but an LS7 might be worth it. If you go that route, check the block all aroud the sleeve very carefully... a buddy of mine that does engine rebuilds found a crack in the block near the crack in the sleeve. He could have welded it, but it was already a lost cause...
ArKay99 is online now   Reply w/quote Quick reply to this message
Extreme taxation, excessive controls, oppressive government competition with business, frustrated minorities and forgotten Americans are not the products of free enterprise. They are the residue of centralized bureaucracy, of government by a self-anointed elite. - Ronald Reagan
Old 01-17-2013, 07:06 AM   #25
jaymsu
DC Crew
 
jaymsu's Avatar
 
Posts: 1,163
Member #67990
Member since: Dec 2007
Location: Novi, MI

My Corvette(s)
TOY4JAY I: 02 EB Coupe, TOY4JAY II: 07 VY Z06, TOY4JAY III (current): 06 Coupe w/ Z51

Thanks: 17
Thanked 9 Times in 9 Posts
So to sleep better at night, I need Valve / Guide / Spring replaced on heads?
(I'm not looking for any HP increase from head work)

If I were to get some reputable shop to do this work, how much should I expect to pay for the work? (head refresh and install)
jaymsu is offline   Reply w/quote Quick reply to this message
06 Arctic White Coupe w/ Z51 : Airaid Intake, XS Power Muffler, Dr. Phil Tuned
SS braided brake line, Bilstein shock
HP+ brake pads (F) / EBC Yellow pads (R) - Other than that,,, it's pretty much stock.
Old 01-23-2013, 10:31 AM   #26
HyperX
DC Crew
 
HyperX's Avatar
 
Posts: 16
Member #42689
Member since: Jan 2006
Location: Cary/IL/USA

My Corvette(s)
2008 Z06 C6

Thanks: 0
Thanked 0 Times in 0 Posts
You need new valves. I am getting mine done this Friday. Going with Stainless Steele ones. Since my heads are going to be done and engine opened up, I am also throwing a mild cam and other things.

I have researched this issue for two years now and was initially very weary about modding my Z. Since my warranty just ran out, I am doing something to get a peace of mind.
HyperX is offline   Reply w/quote Quick reply to this message
2008 C6 Z06
2010 Silverado Crew Cab LTZ 5 inch lift smitty winch
2008 Chevy 1500 Conversion Van AWD
2008 Toyota FJ Cruiser Lifted/warn winch
Old 02-07-2013, 01:56 PM   #27
clogan
DC Crew
 
Posts: 11
Member #51778
Member since: Oct 2006

My Corvette(s)
C6 Z06

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by MEATHEAD1 View Post
Its the valve guide I seen first hand one that was getting ready to go and one that has. As far the year and Gm they filed bankruptcy. So no deal for replacement for me under warranty.
This a very serious problem modded or not.
Yup. My showroom stock 2006 had defective valve guides. Luckily I detected it at 38,000 miles, before anything catastrophic happened. Last month I replaced my cylinder heads with stock heads that had been overhauled by WCCH to replace exhaust valves with stainless steel, and replace stock sintered metal guides with bronze. Cost me 4 grand. but at least I avoided a valve drop, which most likely would have resulted in a blown engine. Some say 50% of all LS7 engines have defective guides. GM's official position is that the numbers are very small, and limited to those produced prior to a certain date. The truth is perhaps somewhere in the middle of these two extremes.

Here's an easy test that every owner of an LS7 should perform: remove your spark plugs, and inspect the threads (yes, threads) for oil. If your plugs have oily threads, there is a strong possibility that your valve seals, and your valve guides, are defective.
clogan is offline   Reply w/quote Quick reply to this message
Old 03-12-2013, 02:22 PM   #28
mx11vette
DC Crew
 
Posts: 7
Member #121152
Member since: Mar 2013

Thanks: 0
Thanked 1 Time in 1 Post
Has anybody looked into or actually used an available kit that gives you phosphor-bronze valve guides and all the tools required to replace your guides yourself? HorsepowerTV.com has a video showing how its done.
mx11vette is offline   Reply w/quote Quick reply to this message
Old 03-17-2013, 09:51 AM   #29
MEATHEAD1
 
MEATHEAD1's Avatar
 
Posts: 1,386
Member #48881
Member since: Aug 2006
Location: FT WORTH/DALLAS TX

My Corvette(s)
ZO6 07

Thanks: 3
Thanked 1 Time in 1 Post
Quote:
Originally Posted by mx11vette View Post
Has anybody looked into or actually used an available kit that gives you phosphor-bronze valve guides and all the tools required to replace your guides yourself? HorsepowerTV.com has a video showing how its done.
I looked into this and its not my first time doing heads.
Goodson is the one place to look for the kits, but when it comes right down to it, if you mess up,,,,, well you know. If you let a CNC machine shop mess up its there cost. jm2cents
MEATHEAD1 is offline   Reply w/quote Quick reply to this message
YES YOU CAN DRIVE IT,,,,JUST MAKE THE FIRST PAYMENT.

I'M a Post Whore <------its official now.
Old 05-09-2013, 07:19 AM   #30
Krooze
DC Crew
 
Posts: 5
Member #123378
Member since: May 2013

Thanks: 0
Thanked 0 Times in 0 Posts
The thing about you are told is enough sufficient for you, but this is not the situation that always follow. if you really want to upgrade then you should check this list.
Fuel cells, Oil ,Hose fittings
Krooze is offline   Reply w/quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Corvette Forum : DigitalCorvettes.com Corvette Forums forums, you must first register.
Please enter your desired user name (12 CHARACTERS MAXIMUM), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Powered by vBadvanced CMPS v3.2.2

All times are GMT -6. The time now is 10:01 AM.




Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
2003-2011, DigitalCorvettes.com - All Rights Reserved