Help, possible bad GM LS7 lifter?
11-05-2007, 05:20 PM
#1
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Help, possible bad GM LS7 lifter? Finished my headswap 2 weeks ago... did a bunch of things at once:
PRC 5.3L Stage 2.5 heads
GM LS1 Headgaskets
GM LS7 Lifters
ARP Head bolts
P&P Throttlebody
ASP Underdrive pulley
RAM Powergrip HD Clutch
RAM Adjustable Master
Hypertech 160 Tstat
Anyway... have maybe 60 miles on the vehicle since the install. I started on my trip up to TSP last thursday to get a retune. About 20 miles out I had to turn around because of a tapping noise coming from the engine. It would fade in and out and also change speed with RPM...
Called TSP and John was pretty sure it wasn't a lifter because they don't have issues with these lifters... anyway he had me check the rocker arms and make sure none of them were loose and they werent. He had me check the preload and they checked just fine. Last thing they had me do was change the oil to 20w50, I did. Noise is still there =/
Any other ideas or how I can figure out if it is the lifter?? Or maybe even what side is the issue?
PRC 5.3L Stage 2.5 heads
GM LS1 Headgaskets
GM LS7 Lifters
ARP Head bolts
P&P Throttlebody
ASP Underdrive pulley
RAM Powergrip HD Clutch
RAM Adjustable Master
Hypertech 160 Tstat
Anyway... have maybe 60 miles on the vehicle since the install. I started on my trip up to TSP last thursday to get a retune. About 20 miles out I had to turn around because of a tapping noise coming from the engine. It would fade in and out and also change speed with RPM...
Called TSP and John was pretty sure it wasn't a lifter because they don't have issues with these lifters... anyway he had me check the rocker arms and make sure none of them were loose and they werent. He had me check the preload and they checked just fine. Last thing they had me do was change the oil to 20w50, I did. Noise is still there =/
Any other ideas or how I can figure out if it is the lifter?? Or maybe even what side is the issue?
11-05-2007, 05:23 PM
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Never know. it could be the lifter, anything is possible. i work gm parts at a reputable dealer. we had an 08 tahoe with like 800 miles on it and a lifter fragmented. GM warranty bought a whole new service engine for that vehicle. I dont know if that is exactly the problem, but im saying i think anything is possible.
11-05-2007, 09:12 PM
#6
my lifter plunger just went out and the car started running and shaking horribly after some hard running on the dyno... I'd say the easiest thing to do is check the pushrods, and see if any are bent... if you have a bent one and you haven't been hard on it, then there's a good chance it's a lifter... if it's not bent, and it's been running fine, then i don't know 
11-05-2007, 10:31 PM
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I'll pull the valve covers once again and check the pushrods but it's just weird it fades in and out... car pulls great without a hiccup... i haven't been hard on it but i have definately broken the tires loose with ease.
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11-12-2007, 01:07 PM
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Well maybe there's an issue with the LS7 lifters. My 6L does the same thing, has from day 1. I replaced the lifters, put in a new oil pump, and have even had the bearings replaced. It carries 40+ psi normal driving, 60+ at WOT, 30+ at idle, but every once in a while I get a lifter making noise. It comes & goes, with no regularity. I guess I need to give Scoggin Dickey a call & see if anyone else has reported this.....WEIRD!!!!
11-12-2007, 03:43 PM
#11
Man thats weird. Did you soak the lifters before installing them?? I have seen people put them in dry before or just dunk them real quick to lube them & not properly soaked them.
I have been running my LS7 lifters since my H/C swap a few months ago. Haven't had a single issue from any part of the install. I soaked my lifters overnight.
I have been running my LS7 lifters since my H/C swap a few months ago. Haven't had a single issue from any part of the install. I soaked my lifters overnight.
11-12-2007, 09:41 PM
#12
