I could really appreciate some help, insight, further thoughts and guidance on my LQ4 project before I commit to tearing it down again fully for an inspection… Here is a detailed run down of what I have done and my history with this project thus far.

Winter of 2012/2014:
- Purchased a 2005 Chevy 2500 with 155,000 kms on the clock, whats that like 200 miles?
- Removed Engine (LQ4), ECM, Full wiring Harness, and 4L80E Transmission.
- Installed said combo into my "Rock Buggy" .. Reworked the factory harness, everything was running GREAT! No codes, no issues, no problems!

Winter of 2013/2014
I decided I wanted to make some mods to this engine, and figured no better way to teach myself more about the LS series engines in the meantime (no previous engine experience)...this is where it all went wrong hah!

- Mods as follows -
•TBSS Intake
•BBK 92mm drive by cable Throttle Body (kept factory IAC, and TPS)
•243 Heads with "yellow" springs (these were already complete, I simply had them "cleaned up" or re-decked locally)
•New lifters and lifter trays (Summit# SUM-HTLSKIT)
•Comp Cams 7.400" Pushrods
•Fresh Head Gaskets, and Head Bolts, (the gaskets used came from this kit, Summit# HS26190PT
•New Oil Pump (Summit# NAL-17801830)
•New Timing Set (Summit# SUM-G6602-B) .. Did not advance/retard/degree the cam, timing would be "0"
•Comp Cam .558 Intake Lift and .563 Exhaust Lift .. Not overly crazy, instead more torque orientated.
•LS3 Injectors (#42, with the required conversion/adapter clips for LQ4 injector wiring)
•After the above, I had the ECM retuned to account for Injectors changes, for my increase in Compression (10:1 I figure with head swap) etc etc

As you can see, I basically did a bunch of what I would consider fairly low-level or easier to install modifications .. However, immediately upon start-up (ignore the fact that I am holding higher revs in the video, didn’t know that wasn’t required on a full hydraulic roller set-up) I had some pretty good noise coming from the valve cover areas! A few other things possible noise related things I should mention here, I am running factory Vette Manifolds, I have NO inner fender wells, no acoustic engine cover etc.


After days and days of searching and reading about "lifter ticks", "sewing machines" etc etc .. I identified TWO area that could be causing me problems,

1. A pinched O-Ring, or
2. Improper pushrod length

I decided to start with pushrods since I never actually measured, a mistake I know but hey, I'm learning right! Being way too impatient, I ordered and installed some 7.425's based on what I have "read online" ... My rational for going to a LONGER pushrod was the thought that this ticking or chatter was a result of the pushrod rattling against the rocker and not having enough preload …

So, for this second set/attempt, I installed the same brand Comp Cams pushrods, this time in a 7.425" length. While I want to think the noise had changed somewhat (hard to recall, few months ago now) … it was still very much existent.

In this video I am holding approx. 2200 rpm as that seems to be when the sound resonates the worst,


Now being totally exasperated and frustrated, I decided I would instead rather lay in a pile of oil and inspect my potential O-ring problems before attempting to mess around with my pushrods again!!… Imagine my surprise when I dropped the pan, and removed the oil pick-up tube. First of all, it was GREEN and I have since read that the LQ4 requires the ORANGE/RED O-ring?? Also I notice that my green o-ring had been pinched and was half torn! See attached picture .. I was so excited that I had found the "problem" here that I rushed down to my local dealer, got a new ORANGE o-ring, carefully installed it and buttoned everything back up. Re-filled the engine, held my breath and fired it up! … Still clicking/clacking/ticking etc .. Major disappointment!

After my o-ring swap, I was back thinking about the various things that could end up causing some excessive noise … I think it should be noted here that the vehicle runs quite well, and seems quite strong. I feel like if I had "major" issues such as a valve sticking opening, or a waaayyy too long or too short of pushrod that the engine itself wouldn't run as well as it does. This in turn leads me back to pushrods YET again, in my mind this noise is being caused by a small issue and isn't anything catastrophic but again, I am new to this.

In any event, after spending $250 on random pushrods, I spent the $20 on a pushrod checker (it's funny to see how many other people online took this same approach heh). I read a number of methods that people use to check for proper pushrod length and settled on the following approach:

- Find TDC on Cyc #1
- Remove Rocker Arms (Intake and Exhaust)
- Set pushrod length checker to a random length, lets say 7.40, then tighten down to ZERO lash .. This is defined as when the rocker is seated on it's pedestal
- If you saw the valve spring compress before reaching zero lash, shorten the pushrod length checker and re-attempt the test
- Re-attempt the process with a slightly shorter length, say 7.35 and if there is NO movement of the value spring, increase your pushrod length and re-check.
- The idea here was to find ZERO lash, then once torqued to spec, this would put the required pre-load onto the lifters themselves.
- Preload is another area we can debate, I have seen numbers vary from 0.020 to 0.090.

So, following the above process, I remeasured and came up with a figure of 7.350" required in order to achieve 0.025" preload … This is what I currently have installed, and the noise still exists! The reason I went for the lower end of the lifter preload spectrum is that I had to have been VERY much near the 0.090" area or higher with my 7.40's or 7.425's installed earlier!!

Here is a current video at idle, the odd background "squeak" you hear is a belt, or pulley or some dirt/debris .. remember, its a 4x4 buggy.

Another thought I had, especially after my above measuring process suggested a 7.350" pushrod was that perhaps I had way too long of pushrod installed earlier and had turned my set-up into a solid system?!? This sent me on a "lifter research" campaign, as you will see above I bought a LS2 lifter equivalent. From what I've found, LS7 lifters have 0.126" travel and LS1 lifters have 0.160" travel … So I think it's safe to say I didn’t bind up the system (and all my previous pushrods etc are in good shape).

At this point, I feel like my only option is to pull heads and give everything a real close inspection … but of course, I wanted to run it past the experts before I commit to another 10-12 hours and the added expense of head gaskets and head bolts .. Knowing my luck, I'll end up with some random head gaskets which will in turn change my head/deck height and will result in me buying a bunch more pushrods

I realize this is a lot of info to wade through, and I've tried to be as precise as I can put please let me know if you have any questions, perhaps about how I installed certain things etc.

Thank you ALL so much for your help, as you can see I am at my wits end here!

Joey

 

How much oil pressure do you have warmed up and after you run it and the oil is warmed up how much air bubbles are on the oil dip stick?

 

Try removing the acc belts to make sure thats not where the noise is coming from. I have heard a ps pump make a noise similar to that.

 

Sorry for the delay getting back to you guys,

I neglected to mention my oil pressure, it is 40 PSI cold at idle, 37-38 PSI warm at idle and climbs to 60 or even 80 easily when getting on it.

There are no bubbles to speak of ... which is I good sign I suppose,

Here is an updated video WITH the belts removed .. I don't run an AC compressor for what its worth. Seems like with the belt off you can really hear the engine a lot better, especially when it's come back down to idle after being revved up!


Speaking of, I did probe around quite a bit using the screwdriver to the ear trick and while I could hear injectors pulsing, and rockers moving etc the noise I am chasing seems to not really be "16 ticks per sec" for example but more like 1-2 ticks. You can hear in the video it seems to be more front end, or even front lower end specific??

I am starting to wonder if maybe there is something wrong with that general area instead of lifters/pushrods etc? Screwdriver to the valve cover does sound decently quiet I think ...

Any ideas? Timing gears (newly installed)? Timing cover? Chain related? Crank Pulley bolt (which I replaced during build)? Crank pulley itself, bent (was pulled off and pulled back on)?

Help!!

 

Does the noise get louder when you give it gas?

 

Pull the cam.

 

Thanks for chiming in guys!

As far as I can tell, the noise doesnt really get louder, it just speeds up .. You can REALLY hear the noise as it comes back to idle after a burp of throttle.

NAFLASH, I have no issues pulling the cam and checking it out, I just wonder if you guys think there could be a different issue I should explore before a full tear-down (it might take me 6-8 hrs to pull the cam I think).

Out of curioisity, what makes you say cam? Just because of the general location of the sound? ...

My eyes and mind might be playing tricks on my now, but my crank pulley bolt appears to have a small wobble to it ..

Thanks everyone!

 

Id say it kinda sounds like a lifter problem but you said you fixed that right?

 

It sounds like valve,lifter, or cam issue. It has to come apart. Have you removed the valve covers and turned the engine over to verify all the rockers are moving and aren't loose?

 

Hey MAC, I have no "fixed" any lifters? .. They were replaced along with the trays when I did the initial build, but I haven't touched the lifters since... They were pre-soaked before install too.

NAFLASH, I'll recheck my torque on all of the rockers and will let you know ...

Sounds like either way I am heading towards a full tear-down eh?

 

When you remove the valve covers unplug the ignition or disable it some way and turn the engine over with the starter. Verify that all the rockers are traveling the same distance up and down. It is a loud knock so if there is any kind of issue it will most likely be obvious. If you find nothing pull the heads.

 

Just seen something very Like your problem a few months back, was a bad lifter (brand New)

Pull covers and check for play on your rockers.

 

Well, I've started the tear down ... So far nothing looking out of place, have pulley the crank pulley/timing cover, and just re-measured the pushrods before I remove them, and pull the oil pump/com for inspection.

I followed the IO/EC method which seemed really straightforward, simply dropped in a known length rod, I chose 7.40" and followed the procedure.

Zero lash was defined as when the rocker stopped clicking which was basically right as the bolt got snug by hand. I ended up with the following numbers:

Cyl 1 Intake 1-7/8 turn, Exhaust 2 1/4 turn,
Cyl 2 Intake 1 5/8 turn, Exhaust 1 5/8 turn,

Perhaps I messed up with the 2 1/4 turn but none the less it reminded me that I previously broke a head bolt and had to replace the head gasket on the side of Cyl #2 ... Ideally I had the same thickness of gasket but looking at the above I am not sure hah!

Either way, I think I'll continue with the tear down and have a closer look at things,

 

I finished the top end tear down this morning and am somewhat happy to report I found nothing out of the ordinary .. kind of wish I would have found a chewed up cam or something.

In any event, I found the timing chain, timing gears, oil pump, timing cover to be in perfect condition, everything was torqued to spec.

The heads, pushrods, rockers, springs all looked perfect, nothing strange ...

The cam itself still looks brand news, and the lifters all were positioned in their trays, they all rolled freely....One item to note, I decided to push on the lifters once removed with an old pushrod and found 5 of the 16 moved/plunged while the remaining were "solid" .. Maybe that's normal, maybe in the morning all the oil will have drained and they will all move, either way I wanted to mention it.

Given I've found nothing strange, I am not sure what to do next .. I continued to poke around and checked the pistons and cylinders for any odd signs, no valve to piston issues, all the cylinder walls look great .. HOWEVER, check out the movement on the pistons within the cylinders, video below .. What are your thoughts? .... This engine has 155,000 kms .. So call it 100,000 miles.

 

Ive never tried, seen, heard of that. How ever ima guess and say too small of a piston? Again idk

 

you have a lifter issue, guessing from here I would say there is dirt in some of the lifters. Noway after all the run time yuou have should you be able to PUSH the plungers in by hand. Those are lifters making the noise you hear, the pull one of them apart and look carefully for dirt. Something is holding the check valves open.

 

Its interesting to note too that the one "weird" preload measurement I had (2 - 1/4 turns) corresponds to one of my "weak/soft? lifters ..

Either way, looks like I need a new set of lifters but can anyone comment on my piston video?

 

have you tried the stock length pushrods !

 

If by stock length you mean 7.380-7.400" (depending on who your asking) .. then yes, I have tried 7.400", 7.425" and 7.350" .. All of which produced the same audible ticking sound.

I supposed with 5 "failed/collapsed/stuck" lifters than any length of pushrod wouldn't have solved the problem.

I am anxiously waiting on new lifters to arrive in the mail and then I hope like hell this engine is silent once and for all!!

The piston movement has me concerned but I think at this point I am going to pretend I didn't see anything .. I wasn't burning oil and didnt have any blow by so am hoping I am OK!

Thanks for your help and insight!

I think RockinWS6 has the right idea with "dirt/grit" in my lifters, it would just be too coincidental to have FIVE lifters all fail in unison without some sort of contaminent type thing, in fact I should take apart and inspect the 5 lifters that have let me down and see if I can find anything

 

Dude, that much piston movement is an issue. Especially near TDC. Sorry to **** in your cheerios. Did you get a warranty on the used engine or hear it run before you tore it down?