Valvetrain noise after cam swap
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Valvetrain noise after cam swap
New to this forum. Ï recently installed a new LSXceleration cam, 206/212 .515/.522 HR112+2, and i now have valvetrain noise. I used the factory springs, which were still in spec. as they were tested by the company that refreshed the heads. Installed new LS7 lifters. Ï installed with the factory 7.385" PR and had valvetrain noise. I then checked pushrod length at 7.257 zero lash. Ï installed 7.325" pushrods and I still have the noise once it is warmed up. Any thoughts on what to try next? I have also re-torqued the exhaust manifolds after about 3 warm up cycles.
#4
When you say factory valve springs, are you talking about the original truck springs, or do you mean the LS3 springs? I think the truck springs are limited to .500" lift, while the LS3 potentially go up to .570" lift before bind (although lift rate and rpm can play a factor).
Is the noise at idle?
Is the noise at idle?
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I was assured by LSXceleration and Blackbear tuning that the factory truck springs are good up to .550 lift. Ï agree that the only viable cause of the noise could be PR length, but I checked PR length on 10 different valves and they were between 7.256" to 7.258" @ zero lash. I went with the 7.325" rods because that put me around .070" preload on lifters. With that preload, it took 1.125 turns on the rocker arm nut to reach 22 ft/lbs. The only noise at idle is heard under the truck and sounds like it is coming from the valley.
#7
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what year truck?
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#9
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I was assured by LSXceleration and Blackbear tuning that the factory truck springs are good up to .550 lift. Ï agree that the only viable cause of the noise could be PR length, but I checked PR length on 10 different valves and they were between 7.256" to 7.258" @ zero lash. I went with the 7.325" rods because that put me around .070" preload on lifters. With that preload, it took 1.125 turns on the rocker arm nut to reach 22 ft/lbs. The only noise at idle is heard under the truck and sounds like it is coming from the valley.
1 full turn is about .079 preload
Your probably closer to .100 Preload.
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Ï went back through my notes and found that my new 7.325" - 7.257= .068" should be 3/4 turn. Ï will recheck today. Either way, the 7.325" rods gave my lifters .068" preload "on paper".