i have been thinking of switching to either brad penn or joe gibbs oils because of thier high zinc levels.

 

Check the Amsoil Z-Rod oil. The 10W30 I bought is in the upper end of the 30W range at 100 degrees C.

 

We had two set fail the same way, no service from yella terra USA or Australia.

 

What was the setup?

 

Yikes ........more bad news about these rockers. I'm really starting to think about replacing mine. I don't hesitate to buzz my motor to 7000 + RPM.

 

I'm no engineer but it looks like they need to strengthen the area around the push rod insert. I would also like to know the i.d. and o.d. of the rocker and the insert to get an idea of what the press fit interference was intended to be. I would think that if it is too tight that it will cause it to crack at the weakest point. If I were in charge of production I would be collecting some data at these points.

Can you see any evidence of the push rod coming into contact with the insert?

 

I missed the photos posted by ROB@CHAMPIONMOTORS. They are right on target to what I was refering to.

 

The new rockers that were sent to me (set number 3) look to have beefier material in the areas that both of my sets have failed at. I'm still going to use them, just not on this build right now. Money is $$ tight now due in part that my 5.9 Cummins decided to break 3 days later (killer dowel pin) and then I snapped a head bolt in its engine this weekend.

So for now, I think I will be putting a stock ls6 cam in my stock ls6 that is sitting in the corner of the garage, and putting that back into the car. I will still plan on putting a transmission brace in, fixing my torque tube, and putting my big A$$ fuel system in, but just not the engine or turbo setup. I will hold on to the LS2 thats coming out for that build late next year.



On the press fit on the YT rockers for the pushrod cup, I never really had a problem with the cup, just the strap of aluminum that holds the rocker body to the trunion. Thats where my failures start, and the crack just runs up the body.

I hate to hear that YT hasnt helped in any way ROB@CHAMPIONMOTORS, they have been very quick and easy each time I had an issue. Heck, I think they keep tabs on my threads lol! The guy I have been dealing with, Jim Petrakis, has been pretty cool and we even have shot the bull via email a few times on my build.

After all of this, I still dont have any bad beef with YT, and I will still use their rockers, just not in an as aggressive cam setup.

 

First set up was a C6 street car with a 427 TTIX turbo kit,AFR225 heads,Comp 926 springs,and HYD roller cam 239/239 624/624 on a 115. Car ran for 5000 miles before they started to break randomly.

Second car was a C5 with a 402 procharger F1 supercharger with AFR225 heads, patriot golds, and HYD roller cam 239/247 624/624 on a 113
Car ran for less than a few hundred miles before rocker push rod cups started to wear excessively.

Called Yella Terra USA said warranty guy was away called back next month,called again said he is not in,called 5 more times said leave a message no return call. Emailed Yella Terra Austrailia twice no reply. Hinson called us to buy rockers, told him story said he would see what they could do haven't heard back from them in months.

On my 02 Z06 TTIX with AFR 245 heads I am running stock rockers with Zinc additive. Tried new comp 1.72 gold rockers had dyno graph nose dive above 5500rpm, to heavy on the nose. Want to use Yella Terras, but afraid they will break on my combo also.

 

Have you spoken with Jim Petrakis? jim@yellaterra.com.au I dont know if they can do anything, but worth sending him an email.

 

Thanks just sent email to Jim, we have sent many email to there tech department listed on their website with no replies.

 

AMSOIL Z-ROD 10w30 Synthetic Motor Oil (Product Code ZRTQT)
(zinc – 1440 ppm, phosphorus 1320 ppm)

More than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.

 

Jim emailed me over a week ago and passed me to someone else, ask for pics sent last Tuesday still no anwser

 

Any updates?

 

Merry Christmas Christian,

I spoke with Shawn this week. He has a set of the Crane prototypes and he said they look really nice. He should have a set of production units for my car soon. As usual, these things take much more time than you hope. I'm actually reluctant to drive my car hard while the YT's are still in there after breaking a couple from two different sets.

 

Merry Christmas to you as well Kevin,

Don't forget to post a picture of those RR...as well as the specs fpr the 1.7 ratio, and their weight over the nose!!!

Christian

 

I gotta pull the valve covers this weekend and look for issues. The engine is making some unusual ticking noises these days. Hoping it's something simple!

 

i just installed a set and man i had to clearance the valve cover and heads. also i marked the rockers with dykem blue and ran the motor looking for contact marks non were found. also i marked the valve stem spun the motor over and checked the contact pattern on the valve , it was centered perfectly. no issues yet. but the are aluminuim and should be replaced after a full race season or 2 yrs. prw makes steel ls3 rockers, but they are still in testing.

 

There is one place and one place only for these rockers.In the TRASH can.

 

Why? If set up correctly with the right valve springs, they will work fine. What's breaking these is aggressive ramp rates and high open spring pressures.