Another Yella Terra failure (round 2)
10-09-2012, 10:48 AM
#1
Melting Slicks
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Another Yella Terra failure (round 2)
2nd time making this, first time the forum logged me out and I lost everything I typed. :/ I will try to keep this one shorter.
So my Z06 broke on me last night. Kinda knew what it was from the sound but when the rocker failed at first I still had all 8 cylinders. This is my 2nd failure of Yella Terra UL rockers of this exact nature. Here is the back story threads;
LS1GTO Thread
LS1Tech Thread
Yella Terra participated in my GTO thread, and was actively watching both threads. I also spoke to one of their engineers from Australia about the failure. I won't go into much more detail other than they stated it was a small batch of below spec material they recieved. They replaced that set free of charge (except the push rods but Vengance sent me a set for free, really stand up guys they were during all of that)
So here I am, 3 years 2 months later, 11,000 miles after the 1st set failed and I have this...
This is a video
At first when I took the valve covers off I did not find this. I only found it when I went to check the push rods to see if one had bent, then I took that video. I decided to go ahead and pull all of the rockers off the car. I now need to pop the intake and valley plate off the engine and send in the bore scope to check the cam/lifter on that cylinder for damage. I got super lucky the first time, I hope I am this time.
I just do not understand why/how this happened. There are tons of guys running this cam or larger with these heads/rockers. The last failure happened on Cylinder 5 intake, now it is Cylinder 1 intake. I called the Yella Terra guy (Doug Smith) who responded in the GTO thread and see if they can help me out any, as I am sure they will want to know of a similar failure. I doubt they will do anything tho as it has be 3+ years since the rockers were replaced. I left a message as he is on vacation.
I am open to suggestions as to where to go from here. I searched Jesel, but one of the first things I found was where one of thier rockers failed the exact same way. lol
So my Z06 broke on me last night. Kinda knew what it was from the sound but when the rocker failed at first I still had all 8 cylinders. This is my 2nd failure of Yella Terra UL rockers of this exact nature. Here is the back story threads;
LS1GTO Thread
LS1Tech Thread
Yella Terra participated in my GTO thread, and was actively watching both threads. I also spoke to one of their engineers from Australia about the failure. I won't go into much more detail other than they stated it was a small batch of below spec material they recieved. They replaced that set free of charge (except the push rods but Vengance sent me a set for free, really stand up guys they were during all of that)
So here I am, 3 years 2 months later, 11,000 miles after the 1st set failed and I have this...
This is a video
At first when I took the valve covers off I did not find this. I only found it when I went to check the push rods to see if one had bent, then I took that video. I decided to go ahead and pull all of the rockers off the car. I now need to pop the intake and valley plate off the engine and send in the bore scope to check the cam/lifter on that cylinder for damage. I got super lucky the first time, I hope I am this time.
I just do not understand why/how this happened. There are tons of guys running this cam or larger with these heads/rockers. The last failure happened on Cylinder 5 intake, now it is Cylinder 1 intake. I called the Yella Terra guy (Doug Smith) who responded in the GTO thread and see if they can help me out any, as I am sure they will want to know of a similar failure. I doubt they will do anything tho as it has be 3+ years since the rockers were replaced. I left a message as he is on vacation.
I am open to suggestions as to where to go from here. I searched Jesel, but one of the first things I found was where one of thier rockers failed the exact same way. lol
Last edited by sabastian458; 10-09-2012 at 11:04 AM.
10-09-2012, 11:04 AM
#2
Race Director
I've broken two also on my LS3 head setup. With all the broken YT's around, everyone is told about a "small bad batch". My valve train has always been well setup. At this point, I have no confidence in them. I'm waiting for new rockers from Crane. They are developing a set based on their race series and I will have one of the first sets. They should be out any week now.
10-09-2012, 11:50 AM
#4
Drifting
I had a YT go on me like your early post. They replaced all of them and I moved on. They were purchased at the right timing for a bad batch. I hope your current failure is not the beginning of a new trend.
10-09-2012, 12:06 PM
#5
Team Owner
Unfortunately, none of us have the information to sort this out but some here are some of my observations. I will be watching this closely as I have a similar setup.
Aluminum typically has a much lower fatigue life than steel. With higher spring forces it would likely get even shorter. Where we fall on the curve with any of out individual setups is anyone's guess, but in general aluminum rockers (at least in my opinion) may be a "maintenance item".
I did run the Crane "Quick Lift" stud mounted rockers for a while. The design seemed to be better from a structural standpoint, the wipe pattern was wide as compared to the Yella Terra rockers. Also, I didn't like the stud mounting as compared to the LS1 type of design (stock, Yella Terra, etc.).
Is there any information on the new Crane design?
Unfortunately, I have some very custom pushrods and changing to a different rocker will likely require a new length pushrod which is an expensive proposition.
OP: Do you have more information on your build (cam, springs, etc.)?
Aluminum typically has a much lower fatigue life than steel. With higher spring forces it would likely get even shorter. Where we fall on the curve with any of out individual setups is anyone's guess, but in general aluminum rockers (at least in my opinion) may be a "maintenance item".
I did run the Crane "Quick Lift" stud mounted rockers for a while. The design seemed to be better from a structural standpoint, the wipe pattern was wide as compared to the Yella Terra rockers. Also, I didn't like the stud mounting as compared to the LS1 type of design (stock, Yella Terra, etc.).
Is there any information on the new Crane design?
Unfortunately, I have some very custom pushrods and changing to a different rocker will likely require a new length pushrod which is an expensive proposition.
OP: Do you have more information on your build (cam, springs, etc.)?
10-09-2012, 12:30 PM
#6
Melting Slicks
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The cam is a 240/244/ .605/.596 112LSA, springs are the Patiot Dual's that came in my TF heads, rated for .650 lift and from what I see it has a spring pressure of 380's where the rockers are rated at 400-420lbs. (however, this is taking information off the internet at face value, I attempted to varify these ratings off the correct sites and the specs are not listed.)
The set that have been on the car were provided to me in Sept of 2009, so unless they ran a completely new batch of rockers after they found and corrected their machining process (extremely unlikely) there is a high probability that the set I have are from the same batch as the defective ones.
I am still waiting for a reponse from my email and phone call.
I can not afford to by a $500 set of rockers every 6,000-10,000 miles. That is retarded to have to do that. I can see if it were a designed failure part like a clutch disk or brake pads or such, but not a rocker arm. The rocker arm should have been designed properly to withstand the loads and stresses from the begining.
At this point I do not know what I will be doing to fix my car. Depending on Yella Terra's response will determine if I continue to use their product or go with another. I do not want to be in this boat agian later.
The set that have been on the car were provided to me in Sept of 2009, so unless they ran a completely new batch of rockers after they found and corrected their machining process (extremely unlikely) there is a high probability that the set I have are from the same batch as the defective ones.
I am still waiting for a reponse from my email and phone call.
I can not afford to by a $500 set of rockers every 6,000-10,000 miles. That is retarded to have to do that. I can see if it were a designed failure part like a clutch disk or brake pads or such, but not a rocker arm. The rocker arm should have been designed properly to withstand the loads and stresses from the begining.
At this point I do not know what I will be doing to fix my car. Depending on Yella Terra's response will determine if I continue to use their product or go with another. I do not want to be in this boat agian later.
10-09-2012, 12:58 PM
#8
Melting Slicks
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Well it is possible to run those, but Trick Flow specifically states to use only roller rockers.
Last edited by sabastian458; 10-09-2012 at 04:07 PM.
10-09-2012, 01:23 PM
#9
Supporting Vendor
I'm running Yella's on LS7 heads. Big cam and spring set up.
I hope the LS7 Yella's 1.8 don't have that issue. I have about 10k miles on them so far.
I hope the LS7 Yella's 1.8 don't have that issue. I have about 10k miles on them so far.
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10-09-2012, 01:28 PM
#10
Melting Slicks
10-09-2012, 01:34 PM
#11
Melting Slicks
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I think I want a steel rocker this time. Or if YT replaces these for me again, I will pick up a spare set to keep in the car with a set of tools and spare push rods. (Starting to have flash backs to my 3000GT VR4 days.....
)
10-09-2012, 02:10 PM
#12
Melting Slicks
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well doing research acording to YT's website, these are covered under the lifetime warranty. Only problem will be getting them to honor it.
What is the warranty on rockers?
STREET TERRA rockers are guaranteed against faulty workmanship and materials for a period of 12 months from date of purchase, subject to conditions below. TELLA TERRA rockers are also guaranteed against faulty workmanship or materials for a period of 12 months from date of purchase. 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.
STREET TERRA rockers are guaranteed against faulty workmanship and materials for a period of 12 months from date of purchase, subject to conditions below. TELLA TERRA rockers are also guaranteed against faulty workmanship or materials for a period of 12 months from date of purchase. 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.
10-09-2012, 04:06 PM
#14
Melting Slicks
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Well I emailed Jesel about their steel rockers and they are $3,500+ with a lead time of 6 weeks. Guess I will continue to let the big boys use those lol!
Called Vengeance and asked for their recomendations. Stock rockers with the trunion upgrade. Guess I will store that away for extreme last resort measures.
Still waiting for any response from Yella Terra, and looking into other shaft mounted roller rockers. weighing options can be stressfull...
Called Vengeance and asked for their recomendations. Stock rockers with the trunion upgrade. Guess I will store that away for extreme last resort measures.
Still waiting for any response from Yella Terra, and looking into other shaft mounted roller rockers. weighing options can be stressfull...
10-09-2012, 04:19 PM
#15
Race Director
This is a pic of the first one that broke. Unfortunately, I had to remove the head to get all the pieces out. The second one broke more cleanly and it was still sitting in the top of the head.
How many "small bad batches" can there be? Fishy...
The new Crane rockers are in heat treating now. Should be soon and I'll post up some info when I get them. I'm still working with Shawn Miller on this.
To the OP. Make sure you find all the pieces and can reconstruct the rocker in very fine detail. You may have to pull the head or even the pan to find all the pieces.
How many "small bad batches" can there be? Fishy...
The new Crane rockers are in heat treating now. Should be soon and I'll post up some info when I get them. I'm still working with Shawn Miller on this.
To the OP. Make sure you find all the pieces and can reconstruct the rocker in very fine detail. You may have to pull the head or even the pan to find all the pieces.
Last edited by WKMCD; 10-09-2012 at 04:22 PM.
10-09-2012, 04:27 PM
#16
Melting Slicks
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There arent any pieces, the part that broke appears to still be attached. However like last time I will have to flush the engine and change the oil. Which is not a bad thing, I am due for an oil change now. The only unknown at the moment is the cam lobe for cylinder 1 intake, weither or not the lifter was bouncing off of it or not.
10-09-2012, 04:32 PM
#17
Melting Slicks
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I take that back, I see in the pic I posted that it looks like the very tip is missing by the pushrod cup. I will look for it and strain the oil when it is drained.
10-09-2012, 04:55 PM
#18
Race Director
Good luck!
10-09-2012, 05:05 PM
#19
Team Owner
One other thought. I found after doing some research that the 5/16" pushrods were flexing at the upper RPM and used dual taper pushrods to eliminate it. Here is a link to that thread: Link. You might want to consider larger OD pushrods. With the TFS heads, some can handle 3/8" pushrods which would be a great option if they fit, and less expense than the dual taper I went with to fit the AFR heads without machining them.
Last edited by vettenuts; 10-09-2012 at 05:07 PM.
10-09-2012, 05:37 PM
#20
Melting Slicks
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Yeah I own a lesser expensive bore scope, but loaned it to a buddy who used it to find a broken ring land.
I need to see what size the Trick Flow push rods I have are, I thought they were 3/8ths but I dont remember. I will do push rod research after I decide what to do about the rockers. Cant buy pushrods until rockers are here and the preload is determined and rechecked.
I need to see what size the Trick Flow push rods I have are, I thought they were 3/8ths but I dont remember. I will do push rod research after I decide what to do about the rockers. Cant buy pushrods until rockers are here and the preload is determined and rechecked.