Truck2007

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.

FFDP

iTrader: (2)

Got a video?

Some new lifters are pretty noisy.

Truck2007

Ï can try to get one tomorrow. Ï recently heard that aftermarket lifters and cams can make some noise but it is just a mild cam.

68Formula

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?

madmann26

iTrader: (7)

If it's sewing machine noise, it's because of PR length.

Truck2007

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.

Jonblarc7

what year truck?

Truck2007

2007 classic ccsb 5.3 L59

1FastBrick

iTrader: (17)

Your math is wrong. Myself, I run them between 3/4 and 1 full turn.
1 full turn is about .079 preload
Your probably closer to .100 Preload.

Truck2007

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".