Shinobi'sZ

I'm little stumped here as this is the second rocker arm that has broken in a month. #7 went exhaust broke and now #6. I was just cruising low rpm down the freeway when both have let go too. On my other modified LSx cars I always used OEM rockers and I pushed a lot of power on one of them for many years and thousands of miles.

Anyway I purchased this CTS V a few years ago and the guy had an LPE 427 and Maggie on it. I've got about 42K miles on the motor, it had 3K on it when I got it, no internal motor issues that I observed and it made 640/800 rear hp/tq on a dyno tune.

As I'm not too familiar with these rockers, if you look at the pics it appears that the top of the rocker actually hit the inside of the head near where the valve cover seats and I'm assuming is why it broke. Do these rockers shift? Please let me know you opinion as I just as soon replace them all since I have the valve cover off.

The heads are 243 casting, will the new LS7 rocker arms fit on the 243 heads?

Jimbo1367

Yikes. Sorry to hear. Best of luck.

Shinobi'sZ

Thanks. At this point I'm just looking for the most reliable replacement.

G Atsma

Are you planning on replacing all rockers or just the affected one(s)?

Shinobi'sZ

Being that one just broke on the other side and I thought maybe it was an isolated incident, and now another breaks on the opposite side, I'm inclined to believe that they will probably all fail at different times and I will continue to get stuck and have to replace as I go.

I'm going to replace all of them.

G Atsma

Not sure you are so inclined, but I would replace them with stock rockers with a bushing-type trunnion upgrade done to them. They are proving to be VERY dependable and the stock rocker is known to be very tough, the stock needle bearings not so much.

Che70velle

iTrader: (6)

You are running an earlier version rocker. YT has replaced what you have with a much stronger version. Contact YT and tell them your story. They will likely help you out with the latest version if your interested.

vettenuts

iTrader: (4)

Responded in your thread on the other forum. You also need to make sure a valve didn't get bent in the process or any other collateral damage.

99 Black Bird T/A

iTrader: (4)

Sorry to hear about the engine issue. Hopefully the motor is OK other than new rockers.


Just how tough is a stock rocker with BTR trunnion upgrade?

The thieves that stolen my 99TA mechanically over rev'd the engine so badly #5 exhaust smacked the piston so hard it blew the keepers off the retainer and the rocker stand broke - but the stock rockers is intact. The rocker appears to still be good. It will of course be replaced.

I'm pretty amazed by the stock design with trunnion upgrade.

Russ K

iTrader: (1)

What are the valve springs specs?

Russ Kemp

kinglt-1

iTrader: (26)

guys are making 1k whp with stock upgraded rockers.

00pooterSS

iTrader: (40)

Looks like part of the rocker came apart and then it bent then became and interference with the head.

If YT doesn't help you with replacement rockers go back to stock. Too many cars making your power or higher with stock rockers and zero issues.

The stock ones are lighter over the nose anyway which will aid in high RPM valve control.

But if you have a super high lift cam above .630 or so, keep the YT, if not, go stock IMO.

bbond105

OP I would contact Tony Mamo at MAMO MOTOR SPORTS. I think he is a Yella Terra dealer, at the very least he can get you a good deal on a replacement set.

big hammer

Stock rockers are fantastic.... for wearing out valve guides if you have heavy spring pressure

99 Black Bird T/A

iTrader: (4)

Thank you Captain Obvious for that deep insight.

Making big hp with the valve train under control doesn't strain the rocker like a valve smacking a piston strains the rocker.

HioSSilver

iTrader: (8)

Double springs are hard on aluminum rockers.

Put a good set of behives on it.

kinglt-1

iTrader: (26)

You asked how strong a stock rocker is with a Trunnion upgrade, so I replied with a simple answer.

RonSSNova

iTrader: (3)

I went through that on my C5. I bought the rockers from a forum member, new in the box.
They came from the time frame that YT had issues. I only used them because I have AFR heads with the bronze guides and AFR said a roller was a necessity.
Trust me, more will fail.

Just find a nice set of stockers, add the trunion upgrade, folks like the Straub bronze bushings these days and don't look back.

You will also need to find a pair of factory rocker stands and will more than likely need to go through the pushrod length measurement stuff.

Ron

Guuseppe'sTA

Man that sucks, can you just grab a stock set and get the BTR Trunion Upgrade I feel like these GM parts are keepers and should only be upgraded a bit and not replaced with another brand these rockers are tough, hope you get it fixed man I hate to hear that a nice motor gets hurt like that.

Shinobi'sZ

I purchased some GM with HD trunnions installed. Hopefully I won't need to mess with the push rod length. The pushrods I think are comp 7.400 1807s, at least that is what is on the side of them. I will have to use the OEM rockers stands with the OEM rockers obviously.