CC 978 springs overkill?
03-18-2004, 08:33 PM
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CC 978 springs overkill? Just ordered some 5.3 L heads that come with dual springs. I'm opting for the CC978 instead of the 977 since I will only have a TR 224 cam. My installer says I only should get the 918's, that duals are over kill. I'm gonna set my rev limiter at 96-9700 RPM. Am I too paranoid about broken springs and valve float?
03-18-2004, 09:57 PM
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Why are you setting your rev limiter at 9700 rpm? I think the stock lifter will collapse well before those rpms or the bottom end will let go etc. If you really want to turn near 9000 rpm you need a solid roller cam not a TR-224 and well built bottom end.
03-19-2004, 02:49 AM
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Originally Posted by bigdsz
Just ordered some 5.3 L heads that come with dual springs. I'm opting for the CC978 instead of the 977 since I will only have a TR 224 cam. My installer says I only should get the 918's, that duals are over kill. I'm gonna set my rev limiter at 96-9700 RPM. Am I too paranoid about broken springs and valve float?
They are great springs
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03-19-2004, 10:02 AM
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I meant 66-6700 on the rev limiter. Currently I have 915's with a 216 220 - .225 .232 Comp Cam and my dyno guy claims I am getting a little valve float at around 6,000 with the rev limiter set at 6,400. That's why I thought it might not be a bad idea to get the dual springs especially since eventually I might go to bigger than 224. Also a 383 stroker could be a possibility.
03-19-2004, 10:24 PM
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I believe overkill is an EXCELLENT thing when it comes to valve springs and breakage issues, etc. unless they cause you some other problems but i don't see what that would be. This one is easy-GET THE MOST DURABLE HARD CORE DURABLE SPINGS THAT YOU CAN AFFORD FOR YOUR APPLICATION AND ENJOY THE PEACE OF MIND AND NEW FOUND POWER!
03-19-2004, 11:09 PM
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Too much spring pressure puts A LOT of stress on the valvetrain- so I'd watch that but doubles with the correct pressure is a good idea. But the spring pressure is just part of what you have to worry about. Spring metallurgy is a HUGE issue. Most race springs are affected a lot by temperature and lose rate quickly with time. Is this bad? Not at all, that's how it was designed- but it's something to be aware of.
I'm not sure if they make them in diameters that will fit into our heads...but check out some offshore powerboat racing engine builders. They have some NEAT engine parts and some incredibly durable springs.
I'm not sure if they make them in diameters that will fit into our heads...but check out some offshore powerboat racing engine builders. They have some NEAT engine parts and some incredibly durable springs.
03-20-2004, 07:35 AM
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I think it's best to keep the car under 2000 rpms until the water temp is at normal and the oil pressure has dropped back to normal. This will allow the springs to fully warm up before beating on the car.
I like doubles a little more safety margin IMO over a single. My car has 987's with a 224 XE-R cam. I have 9,000 miles on the springs and no signs of valve float in the upper rpm. I seldom wind the car past 6,300 because the power peak for my set up is at 5,900 rpms. I think the this will help the 987's last long too compared to lot's of 6,800 rpm.
I like doubles a little more safety margin IMO over a single. My car has 987's with a 224 XE-R cam. I have 9,000 miles on the springs and no signs of valve float in the upper rpm. I seldom wind the car past 6,300 because the power peak for my set up is at 5,900 rpms. I think the this will help the 987's last long too compared to lot's of 6,800 rpm.
