LS7 Rocker Arm Failures

[kelp]

Reports continue to pour in about LS7 rocker arm needle bearings showing up on the magnetic oil plugs. I checked my rocker arms and they appear to be fine, right now.

This is so frequent, that I was wondering if there had been a TSB generated about this?

 

[NORTY]

No "TSB" as of yet, however,BG is very interested to here about "the reports pouring in."


The loose axle spindle nut is coming, though.

 

[kelp]

Check the reports on Corvette Forum C6 Z06. One even has a survey.

Regarding the axle nuts, there was a survey about that too. I solved mine by double nutting them.

 

[Pistol champ]

The gave me GM bulletin document ID # 2007847 that gives info on this problem they say this PI superseded PIP4156
This does not mean any thing to me but maybe to someone. They only replaced the rocker and left the loose needles in the motor and told me that they would come out during future oil changes.

 

[c4c5specialist]

HI there,
It is simply a preliminary document and not a TSB.
It tells us to replace only the bad rockers, based on ticking noises from the engine.
Allthebest, c4c5

 

[augydog]

HI there,
It is simply a preliminary document and not a TSB.
It tells us to replace only the bad rockers, based on ticking noises from the engine.
Allthebest, c4c5

Is there a possibility that the bad rockers could be the " root" cause of the valve springs breaking? :confused

augydog

 

[Ken Olson]

Reports continue to pour in about LS7 rocker arm needle bearings showing up on the magnetic oil plugs. I checked my rocker arms and they appear to be fine, right now.

This is so frequent, that I was wondering if there had been a TSB generated about this?

Hey, a new owner here. First 'Vette. Love it. 2007 z06. First oil change, 6000mi, and needle bearings on the magnet. Runs good, strong, no missing, no noise. Scares the heck out of me to run it hard. The dealer here in SoCal says to bring it in, but the dang car is at another location, 250 miles away. No good dealer there. The oil looked, visually, like there was metal on themagnet, too, but I've got the bearings in a plastic bag, for the guy who looks at it.

I really like the car, though, big time.

Ken

 

[billyz06-2003]

welcome to the cac kelp, hope you get rocker problem solved.Billy

 

[TODD L GRIFFITH]

Anyone recommend roller rockers for LS7 heads? Thanks in advance.

 

[rickvette]

C6 Z06 Rocker Arm Failures

Reports continue to pour in about LS7 rocker arm needle bearings showing up on the magnetic oil plugs. I checked my rocker arms and they appear to be fine, right now.

This is so frequent, that I was wondering if there had been a TSB generated about this?

As discussed on the CAC forum, I am also very concerned with this report as it appears the 2007 LS7 motors are receiving the bulk of reported failures (it could be they have been around a little longer than the 2008"s??)

As described on the CAC, there is a GM bulletin issued and there are vendors that will actually re-build the rocker arms. Has any member had any experience going this route?

 

[augydog]

As discussed on the CAC forum, I am also very concerned with this report as it appears the 2007 LS7 motors are receiving the bulk of reported failures (it could be they have been around a little longer than the 2008"s??)

As described on the CAC, there is a GM bulletin issued and there are vendors that will actually re-build the rocker arms. Has any member had any experience going this route?

I have an '07 Z and am concerned with this issue too. :W

From all the information compiled in the 2 yrs of watching the forums, I would say we don't really need to worry about this problem.

Just check your magnetic oil drain plugs when you change your oil, and if you hear any out of the ordinary noises from the engine, take it in to your dealer to have it checked out.

Remember, you have a 5 yr. 100K miles warranty.

augydog

 

[rickvette]

I have an '07 Z and am concerned with this issue too. :W

From all the information compiled in the 2 yrs of watching the forums, I would say we don't really need to worry about this problem.

Just check your magnetic oil drain plugs when you change your oil, and if you hear any out of the ordinary noises from the engine, take it in to your dealer to have it checked out.

Remember, you have a 5 yr. 100K miles warranty.

augydog

Thanks Augydog-

I agree we have a 100k powertrain on our great Z06's (I also have a 2007). What bothers me is the recommended GM action is only replace the arms that are failed (if one fails I go by the principle the rest will eventually fail!) and the main issue leaving the needle bearings floating around in the motor. We can get teh arms completely rebuild for $275.00 plus shipping but...this involes about a weeks turn around and the labor of removing your existing arms and putting them back on.

At this point I am going to leave it along (at least for now) and I would like to see if GM declares this a recall issue.

Best Regards-

Rick

 

[augydog]

Thanks Augydog-

I agree we have a 100k powertrain on our great Z06's (I also have a 2007). What bothers me is the recommended GM action is only replace the arms that are failed (if one fails I go by the principle the rest will eventually fail!) and the main issue leaving the needle bearings floating around in the motor. We can get teh arms completely rebuild for $275.00 plus shipping but...this involes about a weeks turn around and the labor of removing your existing arms and putting them back on.

At this point I am going to leave it along (at least for now) and I would like to see if GM declares this a recall issue.

Best Regards-

Rick

Rick,

Don't know if you've seen this thread, but c4c5Specialist should know what's going on.

http://www.corvettemechanic.com/forum/showthread.php?t=943

augydog

 

[TODD L GRIFFITH]

I don't plan on using the stock LS7 rocker, although I'm having a hard time trying to find a ones made specifically for the LS7 heads. Katech would be a fine place to start to find out what they have been doing for their "valvetrain enhancements." These guys are spinning 8000rpm. Jesel doesn't advertise a LS7 rocker arm, but they would be most capable of providing a proven rocker that you won't find small parts of trapped wherever they end up.

Here is a blurb that I found interesting.

Dorton said most NASCAR engines these days are capable of revving 9,000 to 9,500 rpm, which is really hard on valve springs. Because of this, spring durability is extremely important. Valve springs are replaced after every race. Valve openings are typically in the 0.800” lift, so most teams run some type of lightweight rocker arms such as Jesel to reduce the stress on the springs and valvetrain. Other GM heads used by NASCAR teams include 23° “Pontiac” heads, which have siamese center D-shaped exhaust ports, 62 cc combustion chambers, 3/4” reach 14 mm spark plug holes. For 9:1 compression NASCAR engines, GM has 18° heads (P/N 10134363). Aftermarket performance heads by Dart, Brodix and others are not allowed under NASCAR rules.

 

[korvettekarl]

My 07 Z has just over 6k on the clock and NO needle bearings in the 3 oil changes I've done so far. I'm not going to worry about it until it actually happens. It's covered by warranty if it does happen. I would like to see some actual numbers of failures. The internet is a great thing but can sometimes make a mountain of of a molehill.

 

[TODD L GRIFFITH]

The internet is a great thing but can sometimes make a mountain of of a molehill.

This reminds me of the valvespring failures on the 06's, but rest assured this is not your average valvetrain. This is just as good as any aftermarket valvetrain from Crane or COMP, comparable in specifications anyway. The problem is it has to be treated with velvet gloves until the oil temperature is hot enough, well above 150 degrees before a visit to 7000rpm anyway to keep things together. Some may be able to get in their Impala, turn the key and hammer the throttle, but this valvetrain has to be hot first. I don't want people that have found needle bearings in the oil to think I'm saying they beat on their valvetrain. I rather have everyone aware of proper treatment, even wear, and what to avoid. If the car has set for a long time, some of the springs have been compressed for a long time. This could lead to breakage also. As for the rockers, ensure not to bang the rev. limiter and make sure the oil is nice and hot before visiting high rpms. The offset rockers just don't look right to me. Shaft mounted rockers would be the answer to keeping the rockers stable during high rpm floggings. One of the big manufacturers will make them for the LS7 and make a killing.

 

[augydog]

My 07 Z has just over 6k on the clock and NO needle bearings in the 3 oil changes I've done so far. I'm not going to worry about it until it actually happens. It's covered by warranty if it does happen. I would like to see some actual numbers of failures. The internet is a great thing but can sometimes make a mountain of of a molehill.

I've changed my oil 3 times also with 4.8K on the clock and none also.

Thus far, I've read about at least 7 or 8 '07 Z owners reporting the needles problem on different forums.

augydog

 

[TODD L GRIFFITH]

Shaft mounted rockers would be the answer to keeping the rockers stable during high rpm floggings. One of the big manufacturers will make them for the LS7 and make a killing.

Correction! I just received my Feb. issue of Vette magazine. On the featured procharged ZO6 build by MTI Racing, it indicates Jesel shaft mounted rockers on LS7 heads. They didn't list the part number, nor can it be found on Jesel's website, but according to this article they do exist. The only way a needle bearing is going to find it's way out, is through the side of the rocker trunion. Keeping the trunion stationary along a shaft will eliminate unintended rocker movement that would allow enough play where a needle bearing could find it's way out. With shaft mounted rockers, valvetrain stability will be dramatically increased and will reduce the chance of valvefloat.

 

[59-62USNVET]

06 ROCKER FAILURES?

Have their been any failures on 06 Z'S?
59-62USNVET

 

[korvettekarl]

TODD, great advise. This is NOT your daddy's Chevrolet. (I seem to recall some OLD marketing) I keep my Z in a heated garage and it is babied until I reach an oil temp of at least 165. Nothing over 2500 on the tach until then.