Possible 1st Yella Terra rocker failure
06-03-2010, 05:22 PM
#66
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yea this is a shame I have a set of Y.T's from 08 on my trick flow heads. used the washer shims supplied which gave me proper pre load on the lifter and all I got 10 k on the motor with over 70 test pulls and 12 grudge races and no problems I also have another LS2 with trick flow head had no shims and Harlem sharp and the Bering race broke and the needles fell out I could only fins 21 out of 27 of them I had changed the oil right after I was hearing the intermediate ticking sound at 2500 RPM's plus's Yella terra are back ordered so I did the trunions on the stock rockers and im told the trick is for them to not hurt the bronze guides is to shim them like them Yella terra's..I did this was able to use the 7.500 trick flow push rods supplied with the heads hopefully I wont have nay problems
05-15-2012, 08:58 PM
#69
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yea this is a shame I have a set of Y.T's from 08 on my trick flow heads. used the washer shims supplied which gave me proper pre load on the lifter and all I got 10 k on the motor with over 70 test pulls and 12 grudge races and no problems I also have another LS2 with trick flow head had no shims and Harlem sharp and the Bering race broke and the needles fell out I could only fins 21 out of 27 of them I had changed the oil right after I was hearing the intermediate ticking sound at 2500 RPM's plus's Yella terra are back ordered so I did the trunions on the stock rockers and im told the trick is for them to not hurt the bronze guides is to shim them like them Yella terra's..I did this was able to use the 7.500 trick flow push rods supplied with the heads hopefully I wont have nay problems
with the stock rocker stand as its has a half round in it for the rocker to sit in ?
cheers
05-16-2012, 01:04 PM
#70
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I would just pick up a set of YT's and rock on.
05-16-2012, 01:10 PM
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I wasn't gonna TTT this post, but since someone else did.
- Ordered a set from Jegs in October 2009
- They failed after 3,500 miles in late Dec 2009
- YT denied warranty
- Jegs honored warranty and sent me a new set in Jan 2010
And whala, this happened yesterday after 10k-12k miles.
- Ordered a set from Jegs in October 2009
- They failed after 3,500 miles in late Dec 2009
- YT denied warranty
- Jegs honored warranty and sent me a new set in Jan 2010
And whala, this happened yesterday after 10k-12k miles.
05-16-2012, 01:13 PM
#72
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From his post it sounds like he put shims under the factory rocker plate. I would not recomend doing this. Some people people will use factory rockers with TF heads, not recomended as the angle on the tip of the valve is different and you begin to gouge it.
I would just pick up a set of YT's and rock on.
I would just pick up a set of YT's and rock on.
05-16-2012, 01:17 PM
#73
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Dang dude. Mine around that time but like the thread says, they warrantied mine very quickly straight from Austraila (spelling?) Knock on wood, all has been good so far. I have, however, been playing with my preload on the lifters this past year, trying to get my valvetrain quieter.
05-16-2012, 04:42 PM
#74
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Dang dude. Mine around that time but like the thread says, they warrantied mine very quickly straight from Austraila (spelling?) Knock on wood, all has been good so far. I have, however, been playing with my preload on the lifters this past year, trying to get my valvetrain quieter.
Then if they make 1600 rockers, up to 16 of them could be bad.
1600 rockers would sell as 100 complete sets.
16 defects spread evenly over 100 sets = up to 16% likelihood you could have at least one defective rocker in your complete set. Some may have more than one reducing the overall odds, I suppose. Still, when you consider the odds that your set may have up a 16% chance of a single rocker failure, they should have done a recall, IMHO. If my math is flawed, feel free to correct me.
Edit:
It also kind of explains why they are reluctant to replace a whole set. I think the odds of having two in the same set would be like (0.16)*(15/99) = 2.4%
Last edited by Capricio; 05-16-2012 at 05:03 PM.
05-16-2012, 04:55 PM
#75
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It's been 20+ years since I took a course in "Probability and Random Processes", but if the guy from YT says it's up to a 1% defect rate, randomly mixed in to the overall production...
Then if they make 1600 rockers, up to 16 of them could be bad.
1600 rockers would sell as 100 complete sets.
16 defects spread evenly over 100 sets = up to 16% likelihood you could have at least one defective rocker in your complete set. Some may have more than one reducing the overall odds, I suppose. Still, when you consider the odds that your set may have up a 16% chance of a single rocker failure, they should have done a recall, IMHO. If my math is flawed, feel free to correct me.
Then if they make 1600 rockers, up to 16 of them could be bad.
1600 rockers would sell as 100 complete sets.
16 defects spread evenly over 100 sets = up to 16% likelihood you could have at least one defective rocker in your complete set. Some may have more than one reducing the overall odds, I suppose. Still, when you consider the odds that your set may have up a 16% chance of a single rocker failure, they should have done a recall, IMHO. If my math is flawed, feel free to correct me.
They also told me Jegs never stocked these so they were dropped shipped and couldn't been from the same batch as my first ones, I disagree there because they came in a Jegs package with about a dozen other parts from various brands.
05-16-2012, 05:24 PM
#77
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The first time, yes. Their answer was their parts "just don't break".
This time they said to send them a ton of pictures and if they determined that it wasn't my fault they would send me a new set once they are off back order in a few months. I have no desire for a third set and I have even less desire to wait months and months without my car.
Jegs will give me a refund and I'm in the market for some Jesel's or T&D's.
This time they said to send them a ton of pictures and if they determined that it wasn't my fault they would send me a new set once they are off back order in a few months. I have no desire for a third set and I have even less desire to wait months and months without my car.
Jegs will give me a refund and I'm in the market for some Jesel's or T&D's.
05-16-2012, 06:14 PM
#78
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yt also deny that there's some DIY trunnion up grades that end up notchey
and have only seen 1% of failure
i sent a link to the posts on here about
unfortunately the link DIDENT WORK i was told ???
all so mast motor sport SAY the yt are not compatable with any of there heads and to only use STOCK or T/D or JESSEL
and have only seen 1% of failure
i sent a link to the posts on here about
unfortunately the link DIDENT WORK i was told ???
all so mast motor sport SAY the yt are not compatable with any of there heads and to only use STOCK or T/D or JESSEL
05-17-2012, 08:41 AM
#79
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yt also deny that there's some DIY trunnion up grades that end up notchey
and have only seen 1% of failure
i sent a link to the posts on here about
unfortunately the link DIDENT WORK i was told ???
all so mast motor sport SAY the yt are not compatable with any of there heads and to only use STOCK or T/D or JESSEL
and have only seen 1% of failure
i sent a link to the posts on here about
unfortunately the link DIDENT WORK i was told ???
all so mast motor sport SAY the yt are not compatable with any of there heads and to only use STOCK or T/D or JESSEL
Yes, I have been hearing about the trunnion upgraded stock rockers failing. I actually had one of the guy's I know fail in is Z06. That happened late last year and I gave him a few of my extra stock rockers to hold him over until the trunnion upgraded ones came off back order.
05-17-2012, 04:34 PM
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I took the rockers off last night and inspected them. I didn't see any signs of excessive wear or side loading/misalignment in the pushrod cup.
I think this failure was caused by one, if not both of these things.
- Per YT, their rockers are only rated to 400# of seat pressure. This is not to say it is the failure point, but the amount of headroom built into the rocker varies and aluminum fatigues.
- Both of my sets of rockers were bought in 2009, when the supposed bad run of YT's were put into circulation.
I found a set of Jesels that I think I am going to pick up. I'm just not confident with anything else and I reliability is key here.
I think this failure was caused by one, if not both of these things.
- Per YT, their rockers are only rated to 400# of seat pressure. This is not to say it is the failure point, but the amount of headroom built into the rocker varies and aluminum fatigues.
- Both of my sets of rockers were bought in 2009, when the supposed bad run of YT's were put into circulation.
I found a set of Jesels that I think I am going to pick up. I'm just not confident with anything else and I reliability is key here.