KGjevre

When the dealer had the valve covers off to replace the two rocker arms with broken needle bearings I got to come by and take a look and snapped some pictures.
The top of one of the valves did not look right to me and today I finally had time to sit down and study the pictures and this is what I found:

Here is a normal looking rocker arm and intake valve top:



Here are two pictures of the bad intake rocker arm with the suspect valve top (note that the rocker arm is just loosely placed and the screw is just started, not tightened down so the rocker arm alignment may be off because of that, in addition to all the needles/rollers missing from the bearing on one side):





On another forum it was suggested that the failed rocker arm had been chewing up the top of the valve, which is what it looked like to me too. What do you think?

-kg

Daylon

'06 Quicksilver Z06

Thats what it looks like to me.

Your car is an '07 if I am not mistaken?????

0Myhardtop

I said it before and I'll say it AGAIN! Please do yourself a favor and replace those stock rockers, and drive worry FREE!

We offer an option/cure to your problems...see the link below. No sales pitch here, this sells it self!

Thanks,
Carlos

SpankUU

I would hope they replace the chewed up valve. It sure looks worn down too.

Gannet

The valve needs to be replaced. And if it's run like that for long on the new rocker, it's liable to damage the facing on the rocker.

426 Hemi

Looks like the good one has a lash cap---and the bad one has lost the lash cap and the rocker was pushing directly on the valve tip.

patch68

Thanks for posting pic's.

jbp8653

Thats exactly right, lash cap gone. When we checked mine rocker looked like his damaged rocker but lash cap was not damaged

tjwong

FYI, only the intake valve which is Ti has the lash cap. The exhaust valve is made of SS and does not require a lash cap. It appears that when the rocker expelled its needle bearings it became out of alignment which in turn eats up the valve tip. I would certainly get your dealer to replace the valve and the rocker arm because it will eventually wear into the new rocker tip.

Do yourself a favor and remove all your rocker arms and send them into Harland Sharp for the modifications, this will alleviate any future issues. Also FYI HS is coming out with a all new full roller LS7 rocker arm replacement which will be coming out soon, it is currently in beta test. I am to receive a set for testing in my personal car.

GrampZ

Exactly.

Needle bearings adios - pushrod then forces rocker to move out of intended plane of motion - beats crap out of lash cap/valve stem tip - eventually resulting in dropped valve and/or possibly wallowed out pushrod holes in head. (Don't ask me how I know - at least it didn't happen with my LS7 yet.)

KGjevre

Thanks, I found this picture on the GM media site when searching for LS7 that shows the intake valve and spring assembly:





I guess the question is how much, if any (I can alwas wish...), of the valve top that was chewed up after the lash cap was gone.

-kg

foremaw

outnumbered

I wonder how many unsuspecting owners had a rocker replaced and they left the chewed valve in.

0Myhardtop

RIGHT!

GM will only take the cheaper way out...that is why I rely on ME to take care of any potential issues.

As you may know, you MUST remove the heads if you need to replace the valves, and that cost GM money. When dealing with warranty work, those goofballs always seem to have a way out of fixing the entire mess the right way...red tape crap

Just remember that in the end, you are going to end up with the same mess that broke in the first place. So why not replace it with the upgraded units from HS and called it day.

Thanks,
Carlos

tjwong

It isn't GM that would intentionally do that. Its the tech working at the dealer and its up to him to properly report that the valve tip was damaged. If he don't say a word no one is going to know any better. GM isn't going to sit there "knowing" that the valve tip was damaged and not do anything about it. The dealer I work with and refer people to has done nothing but top notch work, they would never let something like that slide by.

jimman

Also as far as upgrading rockers, seems like a batch problem, so upgrade to a good one would be as good as an after market one. That way you don't risk loosing your warranty. Now before you flame the stock ones, with the exception of that apparent bad batch they work just fine. Got over 350K miles with 2 LS1's and 1 LS2 and the LS7 with zero problems. So I suppose I could take the advise of someone I don't know on a product that I don't know and replace them, been down that road before. As I've posted before, over 1 million miles with 9 Corvettes and the only problems I've EVER had were with the aftermarket fixalls.

tjwong

Obviously there are a few bad ones (rocker arms) out there. I have seen many. many LSx engines here in my shop with anywhere from a few hundred to 100k+ miles on the engines. I can honestly say I have never ever seen one bad rocker arm in my shop. I can also say that I have been selling the Harland Sharp modded rockers for the last year as an upgrade to my head and cam packages. I sell them mainly because people what peace of mind and it has been as a result of the publicity we have all seen here on this forum. The original service bulletine that was issued by GM concerning this problem not only applied to the LS7 engine but all LS series engines be they be in a Corvette or a truck.

Harland Sharp has been an excellent supplier of quality products to me for some time, granted even they will admit that they did have a issue with the LS1 rocker arms way back when they were first introduced, since then there has been no other problems.

Steve Madsen

All are saying the 06 Zs are safe in this area, but for my own peace of mind I am going to change my rockers. Hmmmm $70,000 investment in fun, and only a few hundred for the insurance for the life of the car. no down time and hassles with warrentee OR NOt.

I am in this vette for the long haul, and will pay to pre repair parts that will or will not fail early.. My 98 C-5 had bearing failure as well.

just my thoughts..

ITS SNOWING AGAIN IN BEND OREGON. COME ON GIVE US GOOD WEATHER, I WANT TO DRIVE....

RedGTS

Isn't the LS7 the only LS engine with a dry sump and remote oil cooler, and therefore the oil heats up much, much more slowly than the other LS series engines? It makes one wonder if beating on it before the oil gets up to operating temp (which takes a *lot* longer than getting the coolant up to operating temp) might have something to do with it. I wonder if the bulletin covered all the engines mainly because the rockers are the same design (and I think they are), or also because GM had experienced failures on the other LS series engines as well. It would be interesting to know what the failure rate is on the LS7 compared to the other LS engines.