the car is a 2004 LS1 GTO and i recently installed a 228/232 .598 .598 113 cam with PRC double springs
(.650 max) and all the goodies.

kept the stock rockers, though.

the last dyno pull finally kicked one of the LS1 lifters that was going bad, so i replaced all the lifters with LS7 lifters.

the noise is unbelievable and even though ive been told its normal, im ver nervous about getting on it.

everything ive ever learned about mechanical anything is screaming in my head, "SOMETHINGS WRONG!"

i know, the controversy runs deep with that topic, but here is the pudding...

check this video out, all rockers are torqued to ~22 is it just me or is this WAY too much play for contact points?

thanks!!

 

i know that being that they are hydraulic there is some play as you see and will make a bunch of noise when you first crank it up when you put the new ones in. What you may be noticing is the lifters are not filled with oil and you are just pushing against the spring inside them. Most hyd. lifters should be soaked in oil to help fill them with oil faster. they usually make a loud clatter if not filled with oil. If it runs for a while and still does this than you may have a oiling problem with the lifters or bad lifters. when you bolt each rocker down spin the push rod with your fingersand see if the drag on the push rods increase when you tighten them down. the big thing to think about is that if it didnt make the noise when you put the cam in it and started when you replaced the lifters and the lifters are the same size when its a issue with the lifters or oiling. Hope this helps

 

Kinda hard to tell by that but as said above once you start the engine the lifters will pump up and take the slack out. They will chatter like hell for a while but will quiet down. I just put togethor an LT1 and it did the same thing just because the lifters were not pumped up. Fire it up and let it run. After it has all pumped up make a video so we can hear the noise. What length pushrods did you use?

 

those are LS7 lifters and theyve been in the car for about 300 miles now.

i got the cam, blew a LS1 lifter and replaced them all with the LS7s. and yes, we soaked the new lifters in oil overnight before we installed them.

it cold starts quietly, sounds great up until she gets into normal operating temperatures.

once she's up in the 190 range, i hear a tick start to come in... hard to tell if its an exhaust leak or if its a lifter... i might just be paranoid because of my previous bad lifter, but it doesnt sound nearly that loud.

after a few minutes of normal driving (2200 rpm range for cruising) or if i get on it for a shift or two (max 6200 rpm) then i hear all the lifters making the well known 'sewing machine' noise.

its loud, but not unbearable.

whats making me nervous is the single ticking i hear before and sometimes above the lifter tick.

i will make a video today and post it up, maybe you guys can help me ID the tick.

thanks for all the advice!!

 

I would say the pushrods are too short. Most every performance can has a smaller base circle on the cam to allow higher lift. Doing this takes away from lifter preload, that is why a longer pushrod is needed to get the correct preload. Mine was doing this same noise when I ran the 7.4 pushrods. I bought a pushrod checker and found out that I had .040 less preload than it was factory. So since they make pushrods in 7.400, 7.425 and 7.450 I went with the 7.425 because I didn't want to go over the factory specs on preload. It helped a huge amout on the ticking sewing machine sound.

 

awesome.

i need to purchase and figure out how to use a pushrod length checker, LOL

dude, your TA sounds absolutely sick.