Engine Noise (with video)

**Camaro98Z/28** · 09-24-2010, 07:37 AM

ONLY when started cold my engine sounds like this

[ame]http://www.youtube.com/watch?v=nBKy9nko5nI[/ame]

This is only when it has sat over night and it isnt at 1st, you give it a little gas it makes the noise after a little bit it quiets down and is barely herd unless flooring it next to a barrier on the hwy.

Oil is fresh and clean and it has maybe 5K miles since I replaced the whole valve train and oil pump/chain/gears.

Is this what I fear and the main bearings starting to go?

Oil PSI cold is at 50, when run HARD itll be at 30, when cruising 15-20 when stopped on a hot day after driving for and hour. The only funny thing I have seen with the gauge is at times when its warmed up itll be at the 30 on the hwy i nail it, it dips down to 20 and slowly climbs, I let off the gas it flies up to 45-50 and then dips back down to 30.

**Camaro98Z/28** · 09-24-2010, 08:48 AM

or could this just be piston slap?

**Smittro** · 09-24-2010, 08:53 AM

Sounds like a lifter to me..

That sudden squeal @ .34 is puzzling tho...

**shady milkman** · 09-24-2010, 09:08 AM

it is piston slap....normal...id seafoam or mopar combustion cleaner it...and then switch to Pennzoil platinum or ultra...since running those two oils my vlavetrain has quieted and my piston slap is just about non audible.

im with you smitto on the sound..i dont quite know what to make of it ..could be a noisy air pump or something...or just a squeaky tensioner that just made a random noise

**Camaro98Z/28** · 09-24-2010, 09:15 AM

Lol the sound at 34 is my phone getting a TXT message, its a sonar ping lol

I did a full vt build less thank 5k miles ago with these

Mods:
TR224 114 LSA, LS2 Chain Gears & Trays, LS7 Lifters, Manley PRs, Texas Speed Ported/Shimmed Oil Pump, SLP SS Hood, SLP SS Grille, SLP Lid, K&N Panel, SLP Bilstein Strut Spring Package, 1LE Front Sway, PS LTs & Y, Magnaflow Cat-Back, TUNED BY JJS PERFORMANCE, Pioneer AVH-4000 HU, All Infinity Speakers.

Oil in it now is 0-30 GC with a mobil 1 filter.

**jakez28** · 09-24-2010, 03:52 PM

mine does the same, pretty sure its a cold start valve is yours is what mine sounds like, cant really tell from that video. does it whistle off after its warm? if you can hear it whistle off it could be a bad low temp sensor or a vacuum leak, or maybe just a cold start valve.

**Camaro98Z/28** · 09-24-2010, 05:38 PM

No whistle ever.
Its only when started after sitting over night.
Ive never herd of a cold start valve on an LS1, what is it and where is it?

**Cutlass** · 09-24-2010, 06:35 PM

Yes, that sounds like piston slap. And your description on how it only happens on a cold start and goes away after it warms up fits perfectly

**Camaro98Z/28** · 09-24-2010, 06:40 PM

Guys Im on cloud 9 about that, seriously. College student loans are pouring in, and I had to take up a job as an entry tech at Sears to start paying bills due to how bad the job market is right now. I really cant afford to take time off and put more money into this thing right now to rebuild the bottom end so soon after rebuilding the top.

**Z28LS1inEUR** · 09-26-2010, 02:55 AM

Hey,

I might have a no bull answer for you. This is a normal occurance that needs corrective action. It is a product of the the Ls1s weak oil pressure system. What happens to some of our LS1s over time is the the Oil pressure weakens, making it harder for enough oil to get through to the top of the engine where the rockers are at. This is why the noise weakens over time as the engine warms up and the oil breaks down- making it easier to travel.

This is how to fix it. The simple easy way to get a high volume oil pump, along with new pick up tube. Now, here is where the problem might persist. If the Valve train has seen a lot of high RPM reving, this will weaken and wear down the surface of or the Valve train. Making the taping sound a permanent problem unless you replace everything from the rockers, springs, push rods and lifters.

This is how I finally fixed my problem.

**Camaro98Z/28** · 09-26-2010, 05:49 AM

It has a Texas Speed Ported/Shimmed Oil Pump LS6 pump but yea I didnt remove the engine to swap the pick up tube. Also as I stated minus rockers it does have a brand new valvetrain.

**Z28LS1inEUR** · 09-26-2010, 08:03 AM

Well, once you replaced the valve train what did you replace it with? If you increased lift, try this.

Remove your valve covers and keep your coils on. Lay some trash bags out and use some cardboard as a splash guard on the cylindr head. Run the motor and listen for the nose. If you dont hear it you need more clearance with your valve covers. If you still hear it, here is my next question.

Did the noise exist prior to the valve swap or after? THere is a wear in phase of like... 1500 to 2000 miles on the valve train before everything seats on to their new sorroundings.

finally, do you have access to a lift? If so i would raise her up so you can isolate the noise with a stethascope. I read a thread on an LS1 Corvete that had the same issues but it wound up being a lose seating someplace on the fuel system that made something tap again the motor plastic components.

**Camaro98Z/28** · 09-26-2010, 03:35 PM

As of on the way home from work today, zero oil pressure, bad rap on the drivers side. Def not piston slap now...

**cpop98ws6** · 09-26-2010, 04:41 PM

Sounds like a spun bearing to me. Ask me how i know!! Time for a new bottom end.

**Camaro98Z/28** · 09-26-2010, 05:18 PM

Funny part is I listend to a few videos but no screaming or squeeling noise just knocking, it isnt leaking so I assume it didnt throw a rod through the block.

**shady milkman** · 09-27-2010, 09:47 AM

Originally Posted by Z28LS1inEUR

Hey,

I might have a no bull answer for you. This is a normal occurance that needs corrective action. It is a product of the the Ls1s weak oil pressure system. What happens to some of our LS1s over time is the the Oil pressure weakens, making it harder for enough oil to get through to the top of the engine where the rockers are at. This is why the noise weakens over time as the engine warms up and the oil breaks down- making it easier to travel.

This is how to fix it. The simple easy way to get a high volume oil pump, along with new pick up tube. Now, here is where the problem might persist. If the Valve train has seen a lot of high RPM reving, this will weaken and wear down the surface of or the Valve train. Making the taping sound a permanent problem unless you replace everything from the rockers, springs, push rods and lifters.

This is how I finally fixed my problem.

are you talking about piston slap ? if so it isnt a oil issue at all.

**shady milkman** · 09-27-2010, 09:48 AM

Originally Posted by Camaro98Z/28

As of on the way home from work today, zero oil pressure, bad rap on the drivers side. Def not piston slap now...

ouch sorry

**Rob00Taws6** · 09-28-2010, 05:56 PM

my 2000 firebird sounds just as bad, at a cold start. the noise eventually diminishes to a audible tick after operating temp. is reached. I always let may car warm up but it worries me not to mention i hate the noise it just does not sound right. Im to the point that im fed up with the knock and want to get a short block. how are the texas speed short blocks the seem affordable? any one ever have problems for a assembly or piston sets or will they all eventually knock? And, is GM doing anything with engines that slap as horrifically as mine and the one in the video?

**SSwt00SS** · 09-28-2010, 06:09 PM

first thing that comes to my mind, after reading about your oil pressure all over, and then again in your post #13, it's a spun bearing. as stated, you need to address the bottom end of the engine.

good luck

**Cutlass** · 09-28-2010, 07:01 PM

Originally Posted by Rob00Taws6

any one ever have problems for a assembly or piston sets or will they all eventually knock? And, is GM doing anything with engines that slap as horrifically as mine and the one in the video?

Its essentially part of the design. Short piston skits. There are alot of engines out there that piston slap, not just GM. It won't cause any durability problems. There are updated pistons out there with a coating on the piston skits that cushions and takes up the clearance on cold starts to prevent the slap noise.