Broken Tella Terra... Again
I have the Extreme springs only for $129 shipped if that helps at all. http://www.briantooleyracing.com/660...l-springs.html
That's what my failed rocker looks like.
In my opinion, YT they have a tendency to fail after valve float and sharp rev limiters/fuel cut off events. That spikes the load on the rocker over the 425 max rating.
My springs were the Patriot Gold with open rate ~375 lbs and .631" / .644" cam lift. A higher spring rate may be contributing factor to early failures. Patriot Extremes springs have ~400 lbs open rate. It may not break immediately but shortly thereafter. Mine broke about 1 mile later after I hit the fuel cut-off. I partially contribute the rocker failure to having 26,000 miles on the springs. There are not many choices of springs for this cam, so I am installing new Patriot Gold and new YT rockers. The alternative for rockers are stock, but I don't like the geometry at high lift. For rollers, there are other rollers but I can't justify $1200-$1500 for Jesel or T&D shaft mounted rockers.
Note that the stock tune has a 6600 rpm fuel cut off. After the RPM drops 225 rpm, the fuel turned back on. If you don't let off the gas immediately, the rpm will bounce up and down 225 rpm quickly. I believe this can cause the valve spring to resonate and spike the open pressure well about the rated open rate.
So the solution may be: RAISE the fuel cut off to 6800 rpm, change the tune to 20 rpm drop fuel cut off, and make sure you keep well away from fuel cut off. I try to shift at no more than 6200 now.
In my opinion, YT they have a tendency to fail after valve float and sharp rev limiters/fuel cut off events. That spikes the load on the rocker over the 425 max rating.
My springs were the Patriot Gold with open rate ~375 lbs and .631" / .644" cam lift. A higher spring rate may be contributing factor to early failures. Patriot Extremes springs have ~400 lbs open rate. It may not break immediately but shortly thereafter. Mine broke about 1 mile later after I hit the fuel cut-off. I partially contribute the rocker failure to having 26,000 miles on the springs. There are not many choices of springs for this cam, so I am installing new Patriot Gold and new YT rockers. The alternative for rockers are stock, but I don't like the geometry at high lift. For rollers, there are other rollers but I can't justify $1200-$1500 for Jesel or T&D shaft mounted rockers.
Note that the stock tune has a 6600 rpm fuel cut off. After the RPM drops 225 rpm, the fuel turned back on. If you don't let off the gas immediately, the rpm will bounce up and down 225 rpm quickly. I believe this can cause the valve spring to resonate and spike the open pressure well about the rated open rate.
So the solution may be: RAISE the fuel cut off to 6800 rpm, change the tune to 20 rpm drop fuel cut off, and make sure you keep well away from fuel cut off. I try to shift at no more than 6200 now.
Last edited by Mez; Sep 9, 2012 at 10:39 PM.
How would you guys rank the Scorpions against the Comp golds? I hear Scorpions have come along way, but I have never really heard anything good or bad about the Comp ones.
Last edited by My6speedZ; Sep 9, 2012 at 03:40 PM.
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If the time comes where I do another engine and i'm buying another set of rollers I probably won't run the yellas again. Just for the simple fact that it did take a really long time for me to get my replacement. Don't get me wrong they sent me another one free of charge, but I had to ship the broken one back and then it was close to 5 and a half weeks before they sent me the new one. Doug said it was a really busy time for him, so I gave him the benefit of the doubt (i was getting it for free) but I hate that something as simple as that had my car out of commission for so long. So in an effort to avoid that whole mess again I would go with another make,
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From: NYC
I've seen them give out new sets, but I've never heard of anyone getting their money back.
And FWIW I TRIED to get a whole new set and told Doug my concerns with another letting go but he didn't really go for it. I only got the one. I even asked for a discount on a new set (which would have been okay)... but yeah he didn't really go for it. He seemed to think mine were produced outside of the time frame the bad batch was produced
even though I offered to email him my invoice for the motor build. I understand what Silverbullet is saying. While my episode with my rockers happened over 6 months ago hell the initial breakage was actually probably over a year ago. Every now and then I'll get a little itch in my head wondering "well jeez I wonder if/when the next one is going to let go?" I might not be 200 yards from my driveway next time.
And FWIW I TRIED to get a whole new set and told Doug my concerns with another letting go but he didn't really go for it. I only got the one. I even asked for a discount on a new set (which would have been okay)... but yeah he didn't really go for it. He seemed to think mine were produced outside of the time frame the bad batch was produced even though I offered to email him my invoice for the motor build.
And FWIW I TRIED to get a whole new set and told Doug my concerns with another letting go but he didn't really go for it. I only got the one. I even asked for a discount on a new set (which would have been okay)... but yeah he didn't really go for it. He seemed to think mine were produced outside of the time frame the bad batch was produced
even though I offered to email him my invoice for the motor build.