91 240

iTrader: (6)

I know there are tons of threads on this, but nothing I can fully put my finger on. I know LS motors are noisy, but this seems a little excessive to me.

My first thought was lifters, but I don’t know. I hear SO many conflicting recommendations on preload - .080-.100 down to .020-.040

Here’s a little bit of background on my original build, my changes and my processes:

01 LQ4 block bored to 4.030” with Wiseco K444x3 pistons
Compstar H Beam Rods
ARP head and main studs
Brutespeed Blower cam (232/240, .595/.608, 114 CL, and 115 LSA)
317 heads, Patriot Gold Dual Springs, stock valves with 3* valve job
LS7 lifters (12499225)
7.350” hardened pushrods
Melling 10296 oil pump
76mm turbo setup that made 608/526 at 8psi

I’ve recently changed from 317 to 823 heads with the following work done.
823 heads with stock valves with 3* valve job
PRC EHT .675” dual spring kit
stock rockers with BTR trunion upgrade
new LS7 lifters (12499225) – soaked in mineral spirits overnight, blown out completely with compressed air, soaked in oil before installation
various 7.275”, 7.300” and 7.325” Tick Performance pushrods due to valve seat differences
This set lifter preload to .062”-.075” across the board
GM LS9 MLS headgaskets
Valvoline VR1 10w30 oil

Below are a couple of videos that hopefully capture the noise good enough:
1. cold start-up (45-50psi oil press) also showing oil pumping up to rockers, so I feel good the lifters are pumping up correctly.

2. Engine up to temp after 20 minutes and noise is still pronounced. Increases with engine speed too. Idle oil pressure is still the same 45ish and increases to 50psi at 2000rpms


I’ve thought about shortening the PR length to get closer to .038”-.050” preload to see how that would work.

I also thought I might have a collapsed lifter or lifters, but every single one was very firm and no slack in the rockers. When measuring PR length, I could definitely feel the plunger working, not anymore after getting oil pressure.

Stock lifters and dual springs not working well together?

Stiff springs slamming the valves closed?

I went ahead and drained the oil and will have an oil analysis done just to be sure nothing is wearing prematurely. oil looked super clean. i've only driven 30 miles since it’s been back together, as I thought it needed a little more time to pump up the lifters.

Would anyone happen to have any thoughts? Maybe something I’m missing?

Thanks

Forcefed86

iTrader: (4)

Get a push rod length checker. Noise us usually from a push rod that is too short without enough preload.

91 240

iTrader: (6)

forgot to mention that part. pushrod length checker was used on every single one, multiple times. spent hours doing this. measured each one to an 1/8th of a turn at zero lash. that's how I got different pushrod lengths.

91 240

iTrader: (6)

bringing this back up to see if any one else had any other thoughts.