Turbo6TA

This rocker arm failure has been going on for a loooong time.

The needle bearings fell out of one of my rocker arms on my 1998 Pontiac Trans Am with the LS1 engine.

Car was just a couple of years old and had less than 20,000 miles on it when it happened.

KGjevre

Yes, and other people have mentioned that too, and there are some bulletins about it as well, but this thread is about the higher then normal failure rate for this the LS7 engines built in about a 6 month period.

billmcc

Yes the 2008's do have problems. My rocker broke at 20,000 miles

erichg1000

Did anybody reply to Dr Ron's post above?

As a new Z06 owner (and a poor one at that) I am fuhreakin out that the slight ticking sound between 1500-2500 sound I hear might be rocker arm bearings missing. I know some people report that noise anyway - my noise sounds like it is coming from the driver side of the motor, it sounds low like it's actually coming from the cam. Mine is an '06, don't know build date or engine build date I'm at work will have to check when I get home. My car now has 21,000 miles on it but I will definetely be pulling the valve covers off asap

jimman

Normal sound

jbp8653

My 07Z back then was one of the cars that had this problem. I will tell you that it made no different sound what so ever and all the bearing where gone from one side of the rocker that went bad. It was actually cocked on the rocker mount and car ran and sounded as normal. They replaced all the rockers and car was perfect for as long as I owned it.

kingpinfarr

Requested info in order of importance:
1. Car Build Date: 01/07
2. Affected: #6 Intake (one only)
3. Mods: Bolt-ons and tune (no cam yet, discovered during cam swap)
4. Car Mileage when discovered: 19k
5. Current Mileage: 19k (car's still apart for cam swap)

Remedied via CompCams trunion upgrade kit. Had to buy a replacement rocker as tip was damaged. Did not damage valve stem or pushrod.

I susepect the vehicle was purchased with a failed rocker as I haven't found debris in the oil pan and no change in performance has been noticed. The vehicle had a mild rock at idle and a barely noticeable lope. During WOT tuning (even with the intake only partially opening) it would run 25-92mph in 4.1 seconds. Can't wait to finish the cam swap AND have it running on all 8 cylinders!

Cloaked323

with him for once.

erichg1000

So all the retaining caps are in their places (used a mirror to get a view of the most rearward) but two of them looked weird. Anybody with experience about this do you think the following this is a problem? Look at the rocker main pin that is in focus - it is twisted and not lined up with the retaining/housing thing. The rocker pin is not fully round it has a flat side to it. The needle-bearing retainer has a hole in the middle that is the same shape - round but with a flat side. On all the rockers except for the one in focus the pin and retainer hole line up so that the flat sides of the round hole are lined up. The one in focus is twisted so that the flat side of the pin does not line up straight with the flat side of the needle-bearing retainer. The pins are shaped like a D and the bearing retainer has a hole in the middle shaped like a D.



In the pic above: Passenger cylinder bank, front of car to the right. First intake valve the pin is straight, lined up with cap. The second rocker is the first exhaust valve - pin is twisted. Third rocker - pin twisted. Fourth rocker - pin is straight and the rest are all straight too.



Above is the same bank from a different angle that shows the other side of those two rocker arms in question. 2nd and 3rd rockers from the front of car (right side of frame) both have twisted pins. The others are straight. Is this a problem? I'm worried that maybe that pin twisting like that could put a little pressure on the cap and let it pop off or be structurally compromised thus leading to failure.

On the driver side bank there were two other twisted pins as well. I didn't take pics of those. The turned ones on the driver side were in different locations like on the third cylinder back.

So the whole reason I checked them - just to be safe of course- is because like many other posters I hear a pretty quite ticking sound at idle and really up through 3300 rpms it gets faster and faster and then drowns out or fades away. can't really tell. So since my rockers are fine - I am suspecting a lifter that is not filling up with oil enough and is clear of the cam until the lobe comes around - and then SLAP it makes a ticking sound because it wasn't in contact with the cam the whole time. Any ideas? This will destroy the lifter, possibly bend the rod, and destroy that lobe and the cam along with it. Or is it just a normal noise. Most people say it's a normal noise.

Bud Meyer

This seems to be an issue I need to pay attention to. My build date is 06/07. Just changed the oil at 20,000. Both magnetic plugs are still clean. I personally change the oil every 5,000 miles.

KGjevre

Looks to me like the "weird" ones are the ones with the valve open, which would mean that the rocker has moved to press the valve down, so it is in a different position relative to the D shaped pin, and thence the reason the flat part of the pin and the cap does not line up?
Someone else with real experience hopefully will chime in! :-)

kingpinfarr

Honestly, I haven't read all 1000 pages to this post, but FWIW, here's my take.

Everyone knows the factory needle bearing design sucks; it's not encapsulated and uses 18 ga sheet metal to form the races. Total crap.

My findings: Lateral slop in the factory trunion leads to excessive lateral movement under all engine speeds, particularly up high. My factory rockers that were still "good" measured 0.025" - 0.035" lateral slop.

I originally toleranced all my CompCams trunions to <0.008". Then a I did a buddy's and consistently got <0.0035" (not a typo, 3.5-thousandths). So I've gone back and tightened mine to <0.003". That's almost imperceptible to the naked eye. They all roll smoothly and fit perfectly.

My suggestions: (1) If you have an LS7 and it sees 6k+ rpms on a regular basis, do the CompCams kit; it's only $130 and 2-hrs of your time. (2) Don't just press the new bearings flush, actually tolerance them for consistency.

Thanks, and hope this doesn't destroy anyone's motor.

prestostark

Okay - I read almost the entire thread and here's what I think I'm doing, since my '07 just dumped needle bearings at 9,000 miles: Go to dealer and have all replaced with new GM parts. When the 5 yr warranty ends next April, take the valve covers off at home and have those comp cams trunion replacements in hand. Remove the rockers and take them to the nearest machine shop (2 hours away) have them press in the new trunions ( and tolerance them!), get back home and install new valve springs and the improved rocker arms. Does this sound like the right course of action?? I'm a newbie to the Corvette - 2nd owner, and I managed to get 300 miles in before I decided to change oil and found the problem. Fugginay.

Rock36

The only Comp Cams trunion upgrade kit I've seen is for the LS1. Do the LS7 and LS1 have the same rockers?

Eric D

Not the same in many ways like ratio and the intake rocker is offset to one side on the LS7. However, the bearings and trunion are the same.

Eric D

Waste of time and money IMHO. The replacements won't have the issue the originals did.

prestostark

Thanks for the clarification on the rocker arms!

RedZ4me

After reading most pages, my eyes hurt.......the one thing I learned about Forum sites is that they are very helpful at times but you can also get too caught up in them and it drives your mind nuts, drive and enjoy. Mine is an 08 but looks like the build date is June 07........I'll worry if it happens I suppose

prestostark

Looks like I'll get the car back Wednesday. GM covered removal of the valve covers, bad rocker arm, removal of the pan, re-install and new gasket, front end alignment ( necessary after oil pan removal), 8 quarts of Mobil-1. I covered the other 15 rocker arms, a new valve spring and labor for those items. Let's hope they got it right, so I can drive it without worry. The sad thing is, I've been more worried about whether or not the dealer will do more harm than good in the grand scheme of things. It's a shame to lose sleep over that. I'll post how my dealer did, after I have a chance to drive the car for a few days...

RedZ4me

Well after reading endless pages of posts, it did bother me a bit so i decided to change my oil tonight........7.6 litres of Mobil 1. As some of you know, I rec'd my car very recently (this past saturday) and taking ownership of my 2008, I felt I had to change it. Car and owner happier now........and both magnetic drain plugs were good.....just some very light grey frost as some of you called it.........all good and normal.