Sup guys I have a gen3 lsx 5.3 out of a Tahoe with Fbody accessories in my 99 mustang gt, and the problem started a few months back when driving my car. Warmed up. At highway speeds and low rpms (m6 car) 5th gear I started to get a tick from the lifters. It was so bad it felt really sluggish and like it was down on a couple cylinders. Well I changed the lifters out with some new(guy said they had 200 miles on them) ls7 lifters and trays and threw it all back together. Everything was good till last night. Got back on the highway. Running 60-65 mph low rpms 5th gear and I heard it again. Sounded like it dropped a cylinder and there was the tick again but this time it stopped after a few minutes (before it would just tick and not stop) this morning I went and got an aftermarket oil pressure gauge and it reads 28-30psi at idle and cruising its about 38-40 or so. It'll spike up to about 40-43 when accelerating and level back off around 35ish

My buddy said I might have a bad oil pump. I'm thinking it to but I just confirmed I have normal oil pressure at temp at idle. Do you think I have some blockage caused by crap from when thebguybi bought the motor from leaving it outside? Oil pick up issues? No low end nock just a tick from the lifters. It's fairly loud I can hear it when I'm driving and at idle/stop lights.
What about installation of the lifters? I looked it up before installing them and itbsaidnthey can go either way? I installed them (from left to right) left two lifter oil holes facing right and the right set of lifters facing left. So one cyl lifters (int/exh) holes are -> -> | <- <- (sorry for that if I confused everybody. Doing this from my phone)

Here's my setup
Gen3 lsx 5.3 iron block
Fbody oil pan and windage tray.
Fbody accessories.
F body crank pulley
F body wiring harness and Ecu
Aftermarket oil press sensor/gauge
Ls7 lifters and trays
Iron 6.0l heads
Stock gaskets.
Stock pushrods

 

Just re-torqued the rockers and started up. Oil pressure was slow coming up but had 28-30psi.
Was talking with a guy and he said change out the o ring on the pickup? Good idea? Change oil pump while I'm in there?

 

I put an ls6 ported oil pump in mine...not running yet but would be something to look into

 

Sounds like oil aeration, happen to me on my LQ4 rebuild, oil pressure was slow to come up but once up, it would stay, even had great pressure @60+, but it would get the tricking bad at cruse and idling, would even come and go at times, what happens is there is a slight leakage at the O-ring which causes air to mix with the oil and since as we know air compresses, it causes your lifters not to work correctly. Now for some bad news, which is for your bearings, over time it causes pitting, you should be able to tell if it has harmed your bearings, if your oil has no glitter you should be fine, get it fix ASAP. I dropped the pan changed the O-ring and bam problem solved and again if you have no glitter in your oil your bearings should be fine happy fixes, peace

 

Oh ok. Nah I just changed the oil and I didn't see any glitter in it ( when draining get some on my finger and check for that) nothing. But I heard this from now 2 ppl about the o ring. Gonna do that ASAP

 

I readjusted the torque on the rockers. Still ticks when its warmed up.(only ticks when warmed up) Have yet to drop the pan to change the o ring on the pickup. But a guy told me I need sorter pushrods now? 7.350 is what he suggested. Should I even attempt to buy shorter pushrods or should I try out the o ring first? Then if that still does it. Order pushrods?

 

I second the o-ring fix especially since the noise is not there all the time. It definetly wont hurt anything to do that

 

Measure pushrod length.

 

I plan to if the weather Is good this weekend I might do it then but here in Texas we have been having some random *** storms and ****. Lol

Is there different lengths from different years? I can measure one and let y'all know.

 

I couldn't tell you that, but you should always measure push-rod length, because every car is different.