LS Rocker Arm Bearing/Trunion Comparison
05-02-2013, 07:40 AM
#68
The Ultra Pro Magnums are awesome rockers. Too bad they dont offer a 1.7 ratio for LS3's. Thats the only aftermarket LS3 rocker body I would use right now. I loved my Yella Terras on my old LS6 but ive seen too many failures on LS3 offset rockers.
05-02-2013, 08:31 AM
#69
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No, I'm not, and neither are the thousands of other people who buy these commonly stocked and sold with cam kit shelf springs TSP sells/sold. Why do I need to upgrade rockers? (There are none that will work with my heads, but I'd like to hear your logic)
This car isn't a driver. It sees ~2000 miles a year, tops
I would not run any more than 400 pound springs on the stock rockers.
As far as TSP cams, they are the main reason people are posting broken valve train parts. Grinding cams that are on the LSK lobes, guys run them on the street, too weak of a spring = broken lifters, trunions, roller rockers...etc. I don’t know what lobes you have, but I am sure with that spring pressure you can control whatever lobes you have. But the weak link may be the rockers/trunions. Maybe the fix is a cam swap, with a 400 pound spring, for reliability. If you plan on keeping the stock syle rocker. Good Luck.
Last edited by 96lt4c4; 05-02-2013 at 12:49 PM.
05-02-2013, 09:22 AM
#70
Since you need the offset rockers, that may be your only choice.
I would not run any more than 400 pound springs on the stock rockers.
As far as TSP cams, they are the main reason people are posting broken valve train parts. Grinding cams that are on the XER lobes, guys run them on the street, too weak of a spring = broken lifters, trunions, roller rockers...etc. I don’t know what lobes you have, but I am sure with that spring pressure you can control whatever lobes you have. But the weak link may be the rockers/trunions. Maybe the fix is a cam swap, with a 400 pound spring, for reliability. If you plan on keeping the stock syle rocker. Good Luck.
I would not run any more than 400 pound springs on the stock rockers.
As far as TSP cams, they are the main reason people are posting broken valve train parts. Grinding cams that are on the XER lobes, guys run them on the street, too weak of a spring = broken lifters, trunions, roller rockers...etc. I don’t know what lobes you have, but I am sure with that spring pressure you can control whatever lobes you have. But the weak link may be the rockers/trunions. Maybe the fix is a cam swap, with a 400 pound spring, for reliability. If you plan on keeping the stock syle rocker. Good Luck.
05-02-2013, 10:00 AM
#71
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It is harder on the valve tips with the stock rockers at that kind of pressure.
05-02-2013, 11:16 AM
#73
Since you need the offset rockers, that may be your only choice.
I would not run any more than 400 pound springs on the stock rockers.
As far as TSP cams, they are the main reason people are posting broken valve train parts. Grinding cams that are on the XER lobes, guys run them on the street, too weak of a spring = broken lifters, trunions, roller rockers...etc. I don’t know what lobes you have, but I am sure with that spring pressure you can control whatever lobes you have. But the weak link may be the rockers/trunions. Maybe the fix is a cam swap, with a 400 pound spring, for reliability. If you plan on keeping the stock syle rocker. Good Luck.
I would not run any more than 400 pound springs on the stock rockers.
As far as TSP cams, they are the main reason people are posting broken valve train parts. Grinding cams that are on the XER lobes, guys run them on the street, too weak of a spring = broken lifters, trunions, roller rockers...etc. I don’t know what lobes you have, but I am sure with that spring pressure you can control whatever lobes you have. But the weak link may be the rockers/trunions. Maybe the fix is a cam swap, with a 400 pound spring, for reliability. If you plan on keeping the stock syle rocker. Good Luck.
With BTR .660 dual springs (155 lbs @ 1.780", 380 lbs @ 1.180", 400 lbs @ 1.130, coil bind @ 1.070")
05-02-2013, 11:46 AM
#74
Did you pop a few of the rockers/trunnion/bearings apart to see if there was any abnormal wear on the trunnion surfaces? Not sure if just moving them and feeling like they are smooth is any real indication of what might be going on.
05-02-2013, 11:52 AM
#75
There's still thousands of comp cams trunions out there surviving just fine on some very healthy cammed cars. When you make thousands of anything there's always a chance some may not get heat treated correctly. If a bad batch got out I wouldn't call all their products trash.
DietCoke - about when (month & year) did you purchase the trunnion kit that went bad on you?
05-02-2013, 11:56 AM
#76
480 lbs is fine with roller rockers and the right lifters. 480lbs on stock 15 degree rockers and a lot of lift in a daily driver? Disaster...
480 lbs on stock LS7 rockers? Still a lot, more than is needed with the right cam profile.
Stock LS7 12 degree rockers have more contact area at .660" lift than 15 degree rockers have at .600" lift. So what the two different rockers will tolerate in terms of total lift and open spring pressure is a lot different.
For what it's worth, the current C6 Z06 N/A record of 9.86 @ 140.8 and the current Corvette 6 speed power adder record of 8.82 @ 161 were both set with springs that are under 440 lbs open pressure. Exhaust spring pressure is under 400 lbs.
Do the math on 161 MPH with a short tire... less than 440 lbs open @ .67X" lift... it's all about the right lobe profile.
480 lbs on stock LS7 rockers? Still a lot, more than is needed with the right cam profile.
Stock LS7 12 degree rockers have more contact area at .660" lift than 15 degree rockers have at .600" lift. So what the two different rockers will tolerate in terms of total lift and open spring pressure is a lot different.
For what it's worth, the current C6 Z06 N/A record of 9.86 @ 140.8 and the current Corvette 6 speed power adder record of 8.82 @ 161 were both set with springs that are under 440 lbs open pressure. Exhaust spring pressure is under 400 lbs.
Do the math on 161 MPH with a short tire... less than 440 lbs open @ .67X" lift... it's all about the right lobe profile.
05-02-2013, 11:58 AM
#78
Last edited by ZeeOSix; 05-02-2013 at 12:16 PM.
05-02-2013, 12:15 PM
#80
I went with the CHE rockers also.. got too much money tied up in the LS7 to chance it with Comp Cams Trunions. I checked my open spring pressure after reading through the thread and I'm at 446lbs. Manley NexTex .700 lift springs. Should be good for awhile.