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It's funny how these "hard to control" aftermarket rockers keep ending up on these 500whp LS1's...
If you have aftermarket heads with bronze guides you need them, but if you have PM guides the money could be spent better elsewhere. I'd say "harder to control" would be a better way to phrase them, you have to admit if they are heavier over the valve that makes them harder to control.
If you have aftermarket heads with bronze guides you need them, but if you have PM guides the money could be spent better elsewhere. I'd say "harder to control" would be a better way to phrase them, you have to admit if they are heavier over the valve that makes them harder to control.
I'm not so sure about this harder to control stuff. I've ran 1.7's and 1.8's on my bolt-on ls6. The 1.7's hs went to 7000 rpm and ran smoother at 6500+ vs the stock rockers. Both had stock springs. I went to 1.8's and changed the springs to accommodate the extra lift and to be honest i have thought about setting the limiter ti 7200.
If you have aftermarket heads with bronze guides you need them, but if you have PM guides the money could be spent better elsewhere. I'd say "harder to control" would be a better way to phrase them, you have to admit if they are heavier over the valve that makes them harder to control.
The YT6645 rockers are the same weight over the nose, if not lighter. Many of the aluminum rockers are actually engineered to have a lower MOI, even with the roller tip. I think we all just saw Mamo turn 7k with YT rockers with about 420lbs open.
Any trunion upgrades allow 10mm or 7/16" bolts yet?
If the side loading is too much for bronze guides, it's probably a good indication that there's quite a bit of frictional losses in the valvetrain there, PM guides or not.
I'm not so sure about this harder to control stuff. I've ran 1.7's and 1.8's on my bolt-on ls6. The 1.7's hs went to 7000 rpm and ran smoother at 6500+ vs the stock rockers. Both had stock springs. I went to 1.8's and changed the springs to accommodate the extra lift and to be honest i have thought about setting the limiter ti 7200.
you are running a stock LS6 cam with 90lb LS6 springs...I am sure any rocker would be ok on that setup. What is being questions is using a pedestal after market RR with high lift cams with valve springs that have 400+ lbs of open seat pressure.
The YT6645 rockers are the same weight over the nose, if not lighter. Many of the aluminum rockers are actually engineered to have a lower MOI, even with the roller tip. I think we all just saw Mamo turn 7k with YT rockers with about 420lbs open.
Any trunion upgrades allow 10mm or 7/16" bolts yet?
If the side loading is too much for bronze guides, it's probably a good indication that there's quite a bit of frictional losses in the valvetrain there, PM guides or not.
Mamo is using a Yella Terra Ultra light PRO 10mm shaft mount rocker. Probably in the range of 900.00. I doubt you would see him running a Harland sharp or Scorpion.
Sorry fellas for NOT ignoring you just super busy and forgot to check. I'm in the end part of the process of having a home built and things have been crazy. Things keep popping up that I have to take care of immediately. I feel I do owe you an explanation because of the excellent replies/responses you all have been giving me.
Anyhow, I now have more questions about which rocker to choose. I'm not saying you guys made it worse at all, believe me I really appreciate it. There's just a lot of information to digest, all of it good.
The control issues concerns me and I have heard of some horror stories of guys I know that have spent both low $$$ and high $$$ with the same issues of failures such as rocker arms breaking. I know there's no real guarantee on any one brand, but I just need a consensus of what has worked best with the least, or no amount of failure.
Bluey, you need to tell us more about your setup and needs. What size engine? Total lift? RPM? Open and closed pressures?
I have a pretty high lift cam (.638) and I wanted something "better". My research led me to Crower rockers. They have material that bridges across above the roller tip, an oil hole that sends oil directly to the pivot point and a slot that gets oil to the roller tip.
Expensive yes but it was slightly less than the Jessel setup. I'm not sure if this is for you but I would consider it the best rocker system for these engines.
you are running a stock LS6 cam with 90lb LS6 springs...I am sure any rocker would be ok on that setup. What is being questions is using a pedestal after market RR with high lift cams with valve springs that have 400+ lbs of open seat pressure.
Yes....but that was my point. The low spring pressure on on the ls6 and it still controlled the valve but seemed to do a better job at it.
Even now with the 1.8's on it which brings lift to about .580 it does fine with not much more spring on it.
Last edited by HioSSilver; Dec 14, 2014 at 06:16 PM.
Bluey, you need to tell us more about your setup and needs. What size engine? Total lift? RPM? Open and closed pressures?
I have a pretty high lift cam (.638) and I wanted something "better". My research led me to Crower rockers. They have material that bridges across above the roller tip, an oil hole that sends oil directly to the pivot point and a slot that gets oil to the roller tip.
Expensive yes but it was slightly less than the Jessel setup. I'm not sure if this is for you but I would consider it the best rocker system for these engines.
Well, I am still in the process of buying parts for an iron block LM7 347 or 383 build with a shot of N2O. The cam I plan to use will have either a .595/.603 or a .612/.615 lift, depending on which build I go with. As far as RPM is concerned, I believe 6800 to 7200 is the range for either of those cams. I know it seems a little bit a head of the game, but like I said before I need real world hands on experience, because of all I have seen and heard people go through.
I'd like to know why they're still anodizing the rockers when that process has been well documented to degrade resistance to failure by fatigue. There's a reason that the yellas aren't.
That's actually something I'm curious about as well. All I can think of is maybe it's a different "type" of anodizing? Kinda like gun bluing. There's a hot and a cold. I don't know. I'd like to find out though.
