I took off my 1.7 Yella Terras today, to find that one had broken. The car has never seen over 6450 RPM, the preload was set correctly, and the proper torque setting was used. I don't know why or how it could have broken. These rockers only have 4000 miles on them. I was planning on selling these, but it looks like I was screwed on that deal.

 

WOW

 

Was it making any noise? What I mean is, did you have a feeling one may be screwed or was everything normal up until you looked at it?

 

I noticed no abnormal noises or any misfires. I didn't suspect that anything was wrong until I took them off today.

 

Maybe if you call YT they will replace it?

 

That makes number 2 since November that I've heard about. I dont know where the other one broke, if it's in the same place you might be able to get them to replace it. I read about the other one on here somewhere, do a search.

Now it worries me that 2 have broke. Combine that with the fact that they turn out to be heavier where they shouldn't be makes me wonder.

 

I'm not fully understanding WHY those would break right there...that doesnt even seem like it'd be much of a stress point.

 

maybe its just shitty material? That sucks. I suppose I'll continue to take my chances with the stockers.

 

From yella terra website:
"We have such confidence in the quality of Yella Terra rockers, we offer a limited lifetime guarantee against breakage of the extruded aluminium arms, precision alloy steel trunnions or shafts and posilok nuts, while you own them. This guarantee is subject to the following conditions. You must be the original purchaser and produce an acceptable original sellers invoice. These warranties do not extend to cover faulty installation or maintenance or to subsequent damage whatsoever. Perfectune engineering, the manufacturer, reserves the right to examine any goods under claim and shall be the sole judge of the validity of each and any claim and repair, replace goods at our sole discretion. All freight charges are the responsibility of the claimant.
"

They are in AU so I would try e-mail first.
sales@yellaterra.com.au

 

Has anyone heard of any breakages on the HS rockers yet? I am finishing up my install on those tonight. In June they will be at a sustained 4750 rpm. Looks like I'll be guinea pigging these ones.

 

Are the pedistal 'mounts' on the heads the exact same height?
If they're off a little bit (one higher then the other) I could see breaking the rocker shaft where it did.

 

I checked both and they are the exact same height.

 

I was the one that Yella Terra said was the first to break their rocker. It didn't break where yours broke. We had pictures but were lost when the PC crashed. Mine broke where the rocker rests against the push rod. Yella Terra is replacing them no questions asked.

 

I would send Yella Terra an e-mail along with the pics you posted. They need to be made aware of this problem. My best guess is that shaft was cracked before you bought the rockers. Probably happened during heat treat in manufacture. All it takes is a stress riser like a sharp edge around the bolt counterbore to get a crack started during quench. The crack would then spread in use until the shaft broke in two.

The rocker arms themselves are pretty good. I have them on a customer Nissan engine that has run for a couple of years of SCCA racing with no problems. Engine speed 8,000 + rpm.

Steve Demirjian
Race Engine Development

 

Man! You weren't kidding when you emailed me that one was broke They should stand behind it though and send you a replacement.

-Jay-

 

Junky

 

I debated for a while on whether these were worth the cash for insurance money. Ended up staying with stockers. This makes me feel ebtter about my decision. Sorry for the problems though. They should replace them with a new set that you can ebay off or something.

 

This is my thoughts exactly, it had to be a fault in that shaft & that mounting bolt hole.
It was likely a faulty material issue.

 

That sucks, I hope that Y/T pays you to send the bad one back so they can analyze it.

I have a set and my motor has 25 pulls on them to 7000 with no ill effects. They are nice quality I would buy them again. (not to take away from your problem)

 

I thought about upgrading my stock rockers to Yella Terra, Since they were on sale. But now I think I might upgrade them to Jesels.