i actually had an engineer from australia call me last saturday about them. He wanted to make sure i sent the entire set back and not just the broken one. he has been reviewing both threads (here and on ls1gto.com) and said that my install was perfect and that he feels it was something in the metalurgy when the billit blanks were made. He was a really awesome guy to talk to.
Really good to hear that kind of follow up from them.
how did your bend the pushrod on the rocker that wasnt broken?
If cylinder pressure wasnt blown down, the intake breaks trying to open against it. I had a customers car do the exact same thing when a exh rocker broke.
A slightly offcenter wipe pattern wont break the back of the rocker arm if thats the only "issue" Stock rockers have about the worst possible wipe/rock across the valve
We been running them for years and had two different sets with a breakage
I have the old style ones, bought in January 2007, and have about 5k miles on them, lots of high RPMs on Patriot 243 heads with their 225/229 580/590 cam.... No issues so far
__________________ 1987 GTA / Miniram'd 383/ TH? / 9" w/4.33s : Far from stock, far from done.... Link to the GTA
This thread gives me even more of a reason to simply replace the needle bearings in my stock rockers. I'd rather run the risk of valve guide wear than catostrophic failure due to a rocker arm going boom.
I have 35,000 miles on my YT rockers for L92 heads. Twice to the track, and literally hundreds upon hundreds of pulls to redline. LS2 with 102,000 miles. I did find when I changed out my valve springs that they were contacting my valve covers. I was shocked to see that since it is quiet as hell with them installed.
Mine were purchased from Texas Speed August of last year...well, either from them or they drop-shipped them to me. Can't remember for sure.
What was the date or batch number on these that have failed. This could be just another issue like Comp had with the bad 918 springs. It need to be tracked down so we know what to look for.
__________________ 74 V8 MGB GT (12.83 on a 75 shot)
LS1/RX7 Rule 3 no V8 RX7's
Custom work and labor for hire PM me!!! My Build thread V8 RX7 Forum
I have about 2000-3000 miles on motor with these and 1 track day with no failures. I purchased these a little less than a year ago from ls1speed. No failures so far. What worries me is some people said they have been running these for years and had different sets break, so I would hate it to be not batch related.
Well that's good to know. Mine are from July 2008, so I feel safe. Hopefully those who ordered it around the dates of other folks will get theirs replaced.
Cliffs:
YT is replacing the set for any failure < 10,000 miles or one year old.
Failure was due to new machining process and quality control mistake.
Failure rate is less than 1%.
First time in 25 years they've had a problem.
Gerry
Quote:
Hi Guys,
As promised ..Weve done our CSI and have following information to provide. I'll follow the QA format request posted earlier
1) What has your team determined is the root cause of the problem?
The root cause was a process and inspection issue.
In November/Dec 2008 we purchased a new HAAS to increase our production capacity to three machining centres making the LS arms. All three machines output ( ie arms ) are conveyed to a single rumbler for finishing. On initial production of the HAAS, the pushrod cup was machined out of spec on some of the LS1 arms (only the 1.7 YT6645). The Ratio is fine but the PR hole diameter was incorrect.
This new HAAS produced arms overnight that got mixed in with the other arms from our existing machines- thus the difficulty in traceability. The team concluded that its a small batch of arms machined with insufficient radius in a critical load area caused by incorrect tooling supply. From Production to assembly to sea freight to the USA and then to US distributors - takes three to four months ( thus the April 2009 time frame)
Our inspection procedure is 20 every 100 arms……weve since increased this to 25 every 100 arms with a change in the number of checks. (see below)
2) Is it a process, materials, or inspection issue?
Isolated it to a process and inspection….it is not material
3) Have you isolated the problem to a lot, production run, etc?
Yes – a small batch but as this item does not have batch segregation after quality inspection we can only narrow it down to a two month assembly period of which only a small percentage were affected
4) Are you waiting until a customer calls with a problem, or have you implemented a proactive recall/replacement campaign for isolated production run?
As the problem only manifests itself under certain conditions that are variable it is not practical to implement a recall. We are talking about a less than one percent failure rate at this time.
5) What have you implemented in your process to ensure this can not happen again?
Reducing the tolerance (variation) on all future production from the HAAS as well as the variables on the checking fixture. "We have implemented a two stage inspection process on all future production (Immediately after machining (stage 1 ) and immediately after rumbling (stage2) . This is the first occurrence of this type of problem in over 25 years of production."
6) Is the the procedure documented
Yes. Our ISO 9001:2008 quality accreditation requires documentation as such
________________________________________ _________________
Guys these few sets are in the field and we have quickly identified them and replaced.
All new sales have no such problem/issue. We apolgize for the inconvienience, its unfortunate, but as mentioned by our QA manager it is the first occurrence of this type of problem in over 25 years of rocker production.
Hope this puts you in the picture. If you have any further questions email me directly at jim@yellaterra.com.au....If you come across other guys in other LS forums that you subscibe to, who have concerns or issues ....pass on my details
i dont care that mine broke because i bought them used for 200 bucks and there the older style .. will i buy a set from a sponsor on here brand new yes after the winter hits
__________________ 2001 Camaro SS SLP..M6 -AFR 205 Heads, LGM G5X3 Cam, Meziere EWP, Yella Terra Rockers, SLP UD Pulley, SLP 85mm MAF, FTP 85mm Lid, Hooker LT's, Hooker ORY with Flowmaster Merge and QTP 4" Cutout, Magnaflow CatBack, Walbro 255, 42# Injectors, FAST 92/92, CenterForce DFX Clutch and 15.5lb. Chromoly FlyWheel, TA Rear Cover, Motive 4:10 Gears, TT2's and 315 Nitto 555R's. "Wanna Get Mopped Up By A Cobra?"......SURE...
