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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Looks like we are back at it....another forum misguided attempt to steer the world away from Yella Terra products again (and for all the wrong reasons).
For the record I plan to post a very in depth post about Yella Terra in the following week to clarify a bunch of things and give the people willing to read and consider a very fresh and enlightening perspective.
After all, few here could be qualified as much as I to discuss this because no one that has posted in this thread has the data and the feedback I do both installing and recommending this product for well over a decade. When you have hundreds......yes literally hundreds of combinations out in the field with your name on it that run these rockers arms that sort of makes you an expert by default on this particular topic. No one posting here is in the position I am to know just how good (or how bad) this product is....and if the feedback wasn't good and they weren't performing for me I assure you I would not be recommending or using them a decade plus later.
Let me sum it up for you. I run Yella Terra Ultralite rockers on 98% of my cathedral engines....95% of my LS3 builds.....and 95% of my LS7 builds. Good chance if you have read about a successful build utilizing Mamo products (be it now or a decade plus ago) it also had a set of Yella Terra rockers included in the build. In fact barring just a few all out race builds, I have run Yella Terra products on pretty much every LS build I have been involved in for close to fifteen years now (Google and you will see how accurate that statement truly is).
Lets talk about the SR rocker kit Josh originally received....clearing up this situation one of the main reasons I even decided to post here. As fate would have it, Josh was literally one of my first three customers to receive the brand new at the time SR kit with the adjustable rocker arms. This was still considered an Ultralite rocker but a beefed up version aimed at a strip/street style build that still allowed a customer to run somewhat modest spring pressure and still have it perform well to 7500 or so RPM's with the right cam lobes (Josh turned his even higher at times hitting 7800 per his own admission). Unfortunately with my leaning on YT to get these rockers finished and shipped, the original mounting system he pictured in a previous post in this thread was a problem (it was not designed properly) and I thanked him at the time for bringing it to my attention. Naturally I relayed the information to the management of Yella Terra right away.....a family business run by a good bunch of people who truly care (more to share on that topic in my thread).
In fact at the time it was me who suggested to Yella Terra to simply use the tried and true hollow pedestal and through bolt style mount for the new SR kit....parts were already on the shelf and the results of those parts proven a thousandth times over. YT was actually attempting to improve the strength of the base with the new mount design but clearly dropped the ball on that particular product not testing and evaluating it prior to shipping. I do feel I was part of that problem as I was leaning on them to ship the SR product that had gone months past the original ETA (and I was feeling the pressure from my customers to get them shipped). Yes....it was a mistake....the first mount design was certainly an oversight on the part of Engineering but we have all made mistakes and I would bet a lot of us would agree its more common in a time constraint situation. Thankfully the fix was a no brainer (utilize the existing mount design that has given us no trouble for over a decade) and its working well to this day both in the SR product being discussed and the much more popular HR product I ship as well. Once alerted of the situation, all the SR kits at Yella Terra were rounded up and retrofitted with the original hollow stand/through bolt design. A there is no question it sucked that Josh had to be the guy to install the original system and alert me to the issues but I certainly stayed in close contact with him and did my best at the time to help work though it and provide him with a fast (and proven) solution to avoid a major setback in his completion date.
When all this was going down I naturally had to contact the other two customers I shipped the original kit to and alert them to the fact they needed to discard the original stands provided and use the new hardware set-up I provided them in the mail shortly after. Neither of those guys had an issue with that situation as most knew the kit was new and understood stuff happens from time to time. Ultimately Josh got his build going (as most of you followed along) and besides solid dyno numbers, the car ran very well.....197 in the standing mile in Texas....took the trophy for another mile event in California (fastest N/A car at that event) and what's funny is I'm positive some favorable comments about these rockers were posted from time to time. The one in particular that I remember clearly was related to how well they held their lash requiring very little in the way of adjustment after the first lash being set. If I had the time I would look for it....hell it may have been in a PM....but I'm pretty sure it was in the original 454 build thread but that's water under the bridge now. Are the T&D's he just purchased awesome.....yep they certainly are but I would be quick to add that while I feel they are the right choice for a certain type of build I know for a fact they are not the right choice for others (not unlike most high performance parts choices we make....the right combination is everything)
To wrap things up (this post is 3X longer than I intended and I apologize for that), the YT Ultralite is a purpose built rocker that I have had incredible success with for well over a decade. They had some teething problems with the original Gen 1 cathedral design 14 years ago and got a bit of a bad rap due to that in spite of updating quickly to a much more reliable Gen 2 design and ultimately an extremely reliable Gen 3 design back in 2011 - 2012. The cathedrals being offered today are still the Gen 3 design and their reliability record has been excellent. Note the newer products more applicable to this thread (my LS7 and LS3 gear) are an even newer 4th gen design and they have been rock solid for me. Results speak volumes here once again. How many Mamo LS7 combos have you seen now rocking dyno after dyno....small cams...medium sized cams....big cams....doesn't matter....every one of them running Yella Terra rockers and the other Mamo cast of characters. Bottom line....they work extremely well....they are cost effective and you guys should be glad you even have this option available if it fits the type of build you are after (which quite frankly is 95% of the guys reading this). Again....more on this in my own thread I will be posting on the topic soon
FWIW I'm away on a brief vacation to the east coast visiting family and just invested three plus hours typing and dealing with this because I felt the need to set the record straight and its a topic I am very passionate (and knowledgeable) about. Theories and valvetrain buzzwords are bullshit when you have hard data and results to compare against them and I'm chock full of hard data and literally 100's of proven combinations going back over a decade....I know what parts work and what parts don't work and I surround myself with proven parts that work. With the proper set-up the YT rocker arm is an extremely capable rocker arm for a very good price....but the price is just a perk. The reason I run them personally and for most of my clients builds is that its a purpose built part the fits the parameters and requirements of my builds perfectly.
I will get into more detail why that's true in the thread I have been discussing when I come up for air after returning to Los Angeles
So you have not tried it? It looks nerdy much like the stock design with an adjustment for the pushrod and a roller tip. Thinking about a solid lifter cam and this may be an alternative to a shaft mount.
I also hear that TSP is developing a roller head pedestal rocker. But neither of them are going perform like the stock rockers in terms of stability or longevity. People can spend $1500 on fixing a problem that isn't a problem. This particular rocker design would only really benefit class racers who are required to use stock heads with pedestal rockers and want the ability to adjust lash. A clean sheet approach to a valve train people are better suited with rockers such as Crowers or T&D shaft rockers.
So the choice is really stock rocker, or Crower shaft IMO. And going too aggressive with the factory pedestals in terms of spring pressure and RPM can lead to some bad results. Something addressed in a shaft system where the loads are distributed.
I’ve seen far more negative and less reliably with roller tips vs the stock design. Not sure why folks keep dropping 100’s when the stockers do just fine.
I’ve seen far more negative and less reliably with roller tips vs the stock design. Not sure why folks keep dropping 100’s when the stockers do just fine.
People like to spend money, and fix non-existent issues by causing more issues. That way they can have a major failure from a new issue caused by the spent money, so that it can never fail from the non-existent problem.
All this and more can be yours for the low, low price of only $1399.95. But wait, there's more, call in the next 15 minutes and I'll throw in this can of valve float....absolutely free.
This is why I don't like the stock rockers, what I call the bearing surface, the actual contact point on the rocker is not consistent across the surface of the rocker with the valve stem , examples of the rockers from my Z06 with 9,200 miles on them. And the witness marks on the intakes show no resemblance to the size of the lash cap diameter.
And the exhaust rockers.
The Crower Shaft Roller tip rocker set up.
My opinion is the off set of the valve stem centerline to the push rod centerline allows for the trunnion bearing clearance to let the rocker twist off the centerline with the load.
In addition, if you see something wrong with the shaft rocker setup, this is not what is in the motor now, don't panic.
And? So you don't like how they look, a part you never see, so spend thousands of dollars on something else? Follow through with why that is actually bad, and why it would need to be fixed, because "I don't like how it looks" isn't a good idea. These are not wheels or stickers.
I agree with Unreal. The wear pattern seems the least bit concerning, the part is hidden from view. They flat out work, even on most HCI combos. If I ever use my Mamo heads on another LS7 I'll be swapping the pedestal adapters on and using new stock LS7 rockers and won't look back.
07-04-2018, 08:45 PM
