CAP1....take a wild guess!

[CAP1]

No, not much better though, RacingJunk.com....

Pulled the valve covers off today to check lash, get to the last one and I see something very alarming. The rocker arm is cracked on on the valve end near the pin support on the top side. Its cracked from the upper left pin all the way through to the top side of the rocker arm. This would indicate a trend, not a one time broke rocker arm, not relishing buying a set of these or a cam.

Ryan Norton

are you using shaft mounted rockers? or stud mounted? if it's shaft mounted, then there may be a posibility of the shaft shifting.

 when we had the 454 in the camaro, we chipped one of the saddles where the main bearing cap sets in. it kept costing us main bearings on that journal.....

 racingjunk..........eeeeeeeee eekkkkkkkkkkkkk!!!!!!!!!!!!!!!!!!

[Strip]

Finally remembered to post this....



This was the carnage last Thursday, the arrow indicates the position of the crack found today.

Strip

[Strip]

The main carnage happened on number 2 exhaust, the crack appeared on number 7 intake.

Strip

[Strip]

Broke another one tonight on the first burnout, luckily (cringe) I bought a spare to throw on.

Finish getting that one on and found another one cracked, nearly identical to the picture already posted.

Looking a one large to get a set of replacements......

 

On the bright side, the entire event got fogged out so we got rain checks!

Strip

[CAP1]

Broke another one tonight on the first burnout, luckily (cringe) I bought a spare to throw on.

Finish getting that one on and found another one cracked, nearly identical to the picture already posted.

Looking a one large to get a set of replacements......

 

On the bright side, the entire event got fogged out so we got rain checks!

Strip

did the same cylinder break th rocker? if it did, then you know where the problem is...if it's a different cylinder, then you may be looking at an entire rebuild.

[Strip]

Different cylinders...looking at low spring pressure.

Strip

[CAP1]

Different cylinders...looking at low spring pressure.

Strip

or quite possibly wrong installed height? causing binding?

i think that low spring pressure would cause valve float....and you'd probably have some possible piston/valve damage too.
 incorrect spring installed height, will cause binding, which would be more likely a reason for broken rockers.

[Strip]

No bind, if anything we aren't pulling enough coil compression and have low over the nose pressure. Right now we are running .700 lift, the spring calls for max .790 and coil bind in the .875 range. This results in valve toss over the nose, valve bounce on close and spring wobble. Cursory spring pressure check puts us at 220-230 seated, a little low for a 2.3 stainless valve. Heads were originally setup by Dart and glanced over by Eagle Racing so I feel installed height is okay.

Strip

[JTs]

this is a long shot but have you checked the rockerarm ratio?

[Strip]

We cracked three in one pass last nite (5 total) at the valve end, thankfully all were caught before breaking. So far so good but the valve is wobbling from lack of control from the spring. Our rockers have minimum .100 clearance to the spring yet are still hitting them. We can see ever so slight witness marks from the retainer/spring hitting the rocker body. We borrowed a set and were able to see this, thankfully we finished out the night with no more broken rockers. Took off the loaners and looking at getting new ones before next race, and springs to boot.

Heres an example...

http://www.youtube.com/watch?v=i_NpzU4pGjc&feature=related

(Not ours but this is whats happening, mine is probably even worse!)

Another, probably close to what ours is doing...

http://www.youtube.com/watch?v=xIDGGTASelo&feature=related

Fast forward to 2:10 ish...

Hard to believe what that spring does!

Strip

[Plazus]

For a minute, I thought you guys were talking about something very suggestive. LOL!

[Strip]

For a minute, I thought you guys were talking about something very suggestive. LOL!

Okay...