Broken Tella Terra... Again
02-29-2012, 06:29 AM
#22
BTW, have you looked up your build sheet yet? I'm curious what your installed height was since you said you had to shim the springs.
02-29-2012, 06:56 PM
#24
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Different thickness lash caps right? Or do you know another way? I'm pretty sure this is how the engines are set up in NASCAR's cup engines now days, using a non-adjustable rocker to take the weight of the tool steel adjusters out of the valvetrain.
02-29-2012, 10:39 PM
#28
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Yella Terra are rated to ~400 lbs open spring pressure. You may want to check to see where your customer set up is at.
Also, if you have valve float, spring pressure can really spike up, so you want to avoid over reving your motor.
Lastly, I've had no problem with my YT with about 20,000 mile on a LPE GT11 cam with .631/.644 lift. I had the Patriot Gold springs checked out and they were right on spec, too.
Also, if you have valve float, spring pressure can really spike up, so you want to avoid over reving your motor.
Lastly, I've had no problem with my YT with about 20,000 mile on a LPE GT11 cam with .631/.644 lift. I had the Patriot Gold springs checked out and they were right on spec, too.
02-29-2012, 10:53 PM
#32
Yella Terra are rated to ~400 lbs open spring pressure. You may want to check to see where your customer set up is at.
Also, if you have valve float, spring pressure can really spike up, so you want to avoid over reving your motor.
Lastly, I've had no problem with my YT with about 20,000 mile on a LPE GT11 cam with .631/.644 lift. I had the Patriot Gold springs checked out and they were right on spec, too.
Also, if you have valve float, spring pressure can really spike up, so you want to avoid over reving your motor.
Lastly, I've had no problem with my YT with about 20,000 mile on a LPE GT11 cam with .631/.644 lift. I had the Patriot Gold springs checked out and they were right on spec, too.
There was no valve float or over rev condition. I was data logging and the motor never saw more then 4000 rpm and that was over an hour of driving. I was dialing in the VVE. If you look closely at the picture, the rocker snapped.... and quite quickly...
03-01-2012, 09:52 AM
#33
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Sounds like you got a set from the "bad batch" that were sold/installed back in spring/summer/fall/ '09. I have a friend that had an '02 Z06, bought them in May, and broke an intake one in Sept. w/ @ 3K on them. There were a few others on the Vette and GTO forums that had the same problems. YT stepped up and replaced them IIRC. Maybe try contacting them and see what they say.
03-02-2012, 10:37 AM
#34
Me and my wife went to get some dinner this evening and on our way home I heard a familiar ticking sound. I pulled the valve cover when I got home and found a rocker arm broke. This makes 2 broken Intake rockers and 1 cracked exhaust rocker.
Is anyone else having bad luck with these rockers?
Is anyone else having bad luck with these rockers?
I just double checked their website and there is no reference as to how much spring pressure they are rated at. Do you have documentation to back that statement up?
There was no valve float or over rev condition. I was data logging and the motor never saw more then 4000 rpm and that was over an hour of driving. I was dialing in the VVE. If you look closely at the picture, the rocker snapped.... and quite quickly...
There was no valve float or over rev condition. I was data logging and the motor never saw more then 4000 rpm and that was over an hour of driving. I was dialing in the VVE. If you look closely at the picture, the rocker snapped.... and quite quickly...
Here is an article that is dated 1-31-2011 and at the bottom is the rep from Yella Terra and it states what rockers are rated for what spring pressures.
http://www.enginebuildermag.com/Arti...cker_arms.aspx
Last edited by 87silverbullet; 03-05-2012 at 02:58 PM. Reason: add link
03-03-2012, 06:24 PM
#35
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I just double checked their website and there is no reference as to how much spring pressure they are rated at. Do you have documentation to back that statement up?
There was no valve float or over rev condition. I was data logging and the motor never saw more then 4000 rpm and that was over an hour of driving. I was dialing in the VVE. If you look closely at the picture, the rocker snapped.... and quite quickly...
There was no valve float or over rev condition. I was data logging and the motor never saw more then 4000 rpm and that was over an hour of driving. I was dialing in the VVE. If you look closely at the picture, the rocker snapped.... and quite quickly...
Per my calculation, the Patriot Gold springs in my car are about 380 lbs open, so I am well within spec. My friend that broke his YT had springs rated at about the same, so YT came to the conclusion that when he hit the fuel cut off at 7000 rpm, there was valve float and the rocker arm experience almost 500 lbs. Makes sense to me. We reset his fuel cut off to 6500 rpm and he has no issues since then. No reason to go to 7000 rpm on his build.
You may also want to look at the total valve train mass.
03-07-2012, 06:24 AM
#36
Launching!
Well....... I broke one yesterday after I picked my car up from the shop. I might have driven all of five miles. I'm at .602/.612 with the cam and comp 926 springs. Springs might be a little much for the rockers I guess. I went back to the stock rockers.... no issues. If I do another set of rockers it'll be a full shaft (Comp or T&D).
Last edited by FLYZNTN; 03-07-2012 at 09:38 PM.
03-08-2012, 09:08 PM
#37
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Well....... I broke one yesterday after I picked my car up from the shop. I might have driven all of five miles. I'm at .602/.612 with the cam and comp 926 springs. Springs might be a little much for the rockers I guess. I went back to the stock rockers.... no issues. If I do another set of rockers it'll be a full shaft (Comp or T&D).
03-09-2012, 07:09 AM
#38
Launching!
I can't say for certain that they were installed correctly. I depended on my shop to do it and they may have screwed up..... happens. That said, they do this for a living and recommended the product so I have to assume they know what they're doing. At any rate, I picked up the rocker arms yesterday and it turns out that one of the mounting bolts snapped in two. The rocker looks fine. I am trying to contact YT and, at a minimum, get 2 replacement bolts and 2 replacement pedestals. I'd really like a brand new set so I can exchange them for something a little more robust. If I only get the bolts and pedestals I'll sell these for 200 bucks and be done with it... lesson learned.
03-09-2012, 07:29 PM
#39
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I can't say for certain that they were installed correctly. I depended on my shop to do it and they may have screwed up..... happens. That said, they do this for a living and recommended the product so I have to assume they know what they're doing. At any rate, I picked up the rocker arms yesterday and it turns out that one of the mounting bolts snapped in two. The rocker looks fine. I am trying to contact YT and, at a minimum, get 2 replacement bolts and 2 replacement pedestals. I'd really like a brand new set so I can exchange them for something a little more robust. If I only get the bolts and pedestals I'll sell these for 200 bucks and be done with it... lesson learned.
If I can do it, then I do it myself. Installation of roller rocker arms are a bolt on operation so anybody with some mechanical ability can do it.
Last edited by Mez; 03-15-2012 at 06:18 AM.
09-02-2012, 09:55 PM
#40
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Well, I had one break today. # 6 intake. Got on it pretty good today a number of times and it broke. Think it was a combination of rev to 600 rpm fuel cut off and Patriot Gold springs with 27,000 miles on my Lingenfelter GT-11 cam which has .631"/.644" lift. Probably got some valve float which can spike the open pressure.
Ordering a new set Tuesdayand installing a set of Patriot Extreme springs.
Ordering a new set Tuesdayand installing a set of Patriot Extreme springs.