Cold Start-Up

[jz28]

Does any ones Ls 1 knock on cold start ups? mine does alittle and then after warm up it quiets down. i use castrol 5w30. does that make a difference? i was told to use synthetic and i wont have that problem. is there maybe an oil additive that will help out?

[konigandy6]

mileage?

[Mr. Hyde]

My old (original) LS1 used to do it with 70K miles on it. The new LS6 doesn't do it (yet) but it only has 3500 miles on it. I am running Mobil 1 in this motor and did run Castrol GT 5W-30W in the LS1 if that matters.

[jz28]

it has 165,000

[Joe00SS]

Mine has 50K and has knocked since the day I bought it in Oct 02, I run Mobil 1 5w30 and just let it warm up a little before I take off. I've heard that it's piston slap but a dealer tech told me it was carbon build up that a good fuel additive would take care of...I've tried many and I'm not convinced any have really helped.

[T-TOPS]

For you guys with this knocking problem try substituting a quart of oil with lucas oil's heavy duty oil stabilizer or if you opt to they also have a sythetic version of it as well. For really worn down engines, you can use 2 bottles of the lucas oil. change your oil every 2500-3000 miles as always. It may take up to 2 oil changes to notice any big improvements but if your engine is in good condition, you should notice a smoother quieter running engine pretty quick. Also use the injector cleaner. One of the little bottles every tank. This will help in the longevity of your engine and fuel system not to mention it will stabilize poor quality fuel. Anyone feel free to chime in, this is only my personal opinion. I use valvoline in my engines. My opinion is based on observation of improvements from several of my own cars and some customers cars. varying from an aray of cars and trucks of many makes and models. I would like to hear other opinions about these products.

cody

[jz28]

Thanks Guys.

[Mr. Hyde]

After I posted, it jarred the old gray matter, and I remembered that there was quite a bit of noise about this a while ago on the web. Not sure if I can still dig those old things up but more than a few people were upset with this problem. It was described as piston slap, and GM got their lawyers involved, there were lawsuits, etc...
It seems that GM DID admit to the problem in a round about [Lawer speak] way, but also quickly pointed out that it was well within the "normal" range of operational tolerances, and that there was nothing to worry about folks.
I recall this because this was about the time that I went out at 2am as always to take my, at the time DD Camaro to work, when all of a sudden, the rod let go and I have never heard a more horrific sound in my life! At a cold start! Nope, wasn't racing anyone, take great care of the car...bla bla bla, and the rod let go and I had a drive thru block!
So naturally as a human, the first thing I want to do is blame someone. Of course the piston slap had nothing to do with it..
or did it......

[twozs]

gm makes some of the nosiest motors out there . i had a 4 cylinder called the tech 4 in a 87 century that was so noisy i thought it would throw a rod any minute. replaced the motor and the brand new motor was just as noisy. what a waste of time and money . the new motor ran 60,000 miles before i junked the car noise and all

[Mr. Hyde]

Ha! I've heard those motors! They make your average Briggs and Straton lawn mower sound like a Lexus. Also reminds me of my old Vega, that thing was a noise maker too. Shoulda dropped a V8 in it.

[1bad69maro]

Try using some BGMOA its known to coat the piston walls and quiet down that know you hear from what GM calls normal piston slap (let me know how it works for you)

[Insert]

Alright, i work at a auto machine shop. I had this knocking problem when cold as well. So i rebuilt my engine. problem was solved, it was piston slap. but my car had 40,000 miles... and well, piston slap is not very common in cars with only that much mileage.

for those that dont know, piston slap is basically pistons are worn out or undersized. As they move through the cylinders htey have a little bit of clearance on the sides, and they knock the sides of hte cylinders. hence the name, piston slap.

BTW, does anybody find that they have noisy lifters on their LS1? because mine has always been like this and even after rebuild and new lifters, lifters are still noisy.

[Mr. Hyde]

You couldn't help yourself could you? You fix one problem, and open a can of worms! lol j/k

[t-rock]

all of my ls1's have had piston slap or knock at cold start.

[Insert]

You couldn't help yourself could you? You fix one problem, and open a can of worms! lol j/k

its part of the problem of working in a shop. you have the tools and the knowledge to do anything.... and so you want to. unfortunately this takes lots of time.... and ends up with me spending lots of time after-hours in shop.

but yea, i wouldn't worry about the knocking... or clicking... just a pet peeve of mine. The general consensus is that the LS1 is a bit of a noisy engine. And if anyone ever mocks the sound of the engine... just show them how it burns rubber.

[Sweet Chops]

Note 50,000 on the motor. I have always used Mobil 1 5w-30. This summer I decided to try Mobil 1 10w-30 just to see if it would quiet down the slap. I did a little but it is still there.

Ryan

[knappbunch]

have 02ss with sts turbo did not notice knock at 5lbs of boost when i bought the car with39,000 on it but now with 8.5 lbs and 41000 it kncks on cold start if I warm it up no noise. very annoying plus I run mobil one 5/30 tried royal purple synthetic made noise worse.

[random-strike]

i seriously doubt its pistol slap, ls1 use HE pistons correct? they have very little expansion and should have very tight clearences.

my valves seem to tick slightly with 10w30 synthetic

[00maroz28]

59 k 2000 z28... she knocks when shes cold... never effected anyhting though

[67CamaroRSSS]

I thought piston slap when cold and noisy lifters was part of the design???






Note: NOT piston slap but it was as close as I could find