Valve Knock - 2000 5.3

Smitty00Z71 · November 14, 2001

Ouestion, I have a 2000 Z71 and it has a very slight valve knock sometimes. I was wondering if I should have the dealer look at this since my warranty will be expired in a few months. Since this isn't a big problem I'm arraid they would screw it up more then it is by tearing the engine apart. However, I don't want this to become a bigger problem in the long run. P.S - I run 87 fuel.

chevy4x4trucks · November 14, 2001

Welcome to the club, just about everyone's engines knock. The dealer doesn't do anything about it, they say that it's supposed to sound like that. I have heard that some will clean out the fuel injectors and that helps, but it doesn't eliminate the problem.

Smitty00Z71 · November 14, 2001

Yea, maybe I shouldn't mess with it. I just don't want it to get worse later down the road when the truck is out of warranty.

chevy4x4trucks · November 14, 2001

Another post a month or two back one of the guys was going to change his spark plugs to copper plated ones since they would disapate heat faster, or something like that. I would like to know if that fixes the problem, but i don't remember seeing a follow up to it.

jst4f · November 14, 2001

From my scan of this BB, it seems a lot of people are having ping or knocking with their 5.3L engine. The 5.3L Vortex (Silver) engine has a compression ratio of 9.5:1 and GM recommends using 87 octane gas while the 5.7L Vortex (red) engine with a compression ratio of 10.1:1 and must use 91 octane fuel. That is a very small difference in compression ratios with a big difference in octane. Maybe GM called it too close and the 5.3L engines should be run with 89 or 91 octant gas. Maybe a new clean engine can run fine with 87 octane but as is ages, the higher octane is needed. This whole theory falls apart if no one with a 4.8L Vortex engine is having pinging problems because it also has a compression ratio of 9.5:1.

As a side note: I was at a performance shop last night on the web, Jet Performance. They sell after market chips etc to boost engine performance and they require 91 octane fuel for the 5.3L engine. (www.jetchip.com)

jst4f

Smitty00Z71 · November 14, 2001

Makes sense, If I run 89 octain I don't get any knocking.

CapnDean · November 14, 2001

Smitty: I am the resident amatuer/expert on engine ping (Just kidding). I do feel qualified to offer a suggestion for you because I fought Daimler Chrysler for over a year and wound up suing to have my 1999 Ram (with 318 V-8) repurchased as a lemon. I succeeded and despite having the Chrysler biased arbitration boar rule against me twice....I won the suit.

That being said, I am infinitely familiar with PING and what NOT to do about it.

If it is just a little bit when you accelerate uphill or have a heavy load & 87 octane gas (and your mileage is what it should be)....ignore it. Unless you pop and ping really bad all the time...you are likely to screw yourself trying to fix it.

Why? The only 'real' fix...is to retard your timing. When you retard your timing you do so risking loss of performance.

My case against Chrysler:::: My truck pinged so bad that despite premium gas, very retarded timing (piss poor acceleration and 8mpg) my truck STILL pinged and even burned a valve before it had 9K miles on it. Totally Unsat.

Dodge warned AGAINST using premium fuel because of it's high "Driveability Index" and the affect it would have on carbon build-up. So in a small way - - The cure for ping (91 Octane) can increase carbon build-up which can effectively raise your compression ratio which can in turn cause your engine to pre-ignite.

I can essay for hours on it because I had to learn it to fight Chrysler. If your ping isn't TERRIBLE...don't worry about it.

BTW: Optimum performance is achieved in an engine that it operating right on the threshold of ping. That's why drag strip cars don't use knock sensors....a knock sensor briefly retards timing when it senses a knock which can hurt your 1/8 or 1/4 mile time.

[email protected] email me if you'd like a couple of cheap fixes to try before you start hammering the dealer!

chevy4x4trucks · November 14, 2001

Quote from jst4f, posted on Nov. 14 2001,09:46

From my scan of this BB, it seems a lot of people are having ping or knocking with their 5.3L engine. The 5.3L Vortex (Silver) engine has a compression ratio of 9.5:1 and GM recommends using 87 octane gas while the 5.7L Vortex (red) engine with a compression ratio of 10.1:1 and must use 91 octane fuel. That is a very small difference in compression ratios with a big difference in octane. Maybe GM called it too close and the 5.3L engines should be run with 89 or 91 octant gas. Maybe a new clean engine can run fine with 87 octane but as is ages, the higher octane is needed. This whole theory falls apart if no one with a 4.8L Vortex engine is having pinging problems because it also has a compression ratio of 9.5:1.

As a side note: I was at a performance shop last night on the web, Jet Performance. They sell after market chips etc to boost engine performance and they require 91 octane fuel for the 5.3L engine. (www.jetchip.com)

jst4f

I've got the 4.8 and it pings wheter I use regular or premium. Although that's all thrown out when you throw in the fact that I'm running reformulated gas.

Smitty00Z71 · November 14, 2001

Thanks for the advice. The ping is just how you describe it, very sight sometimes going uphill with the A/C on generally on a warm day. I have also heard other people say a slight ping or knock is normal, I think I'm not going to worry about it. I have decided to buy an exteneded warranty (5yr, 75K) because my factory warranty is almost up. If the ping ever becomes a problem I will have this warranty to fall back on. Thanks again for the advice.

GreenRado · November 14, 2001

chevy4x4trucks

I wonder if your "pinging" is the dreaded "bearing knock" that seems to plague some of the '99 and newer Vortec models? At least that's what I understood last time I heard about this. I have never had any classic pre-ignition with my '99 5.3, even when I mistakenly put in 85 octane in Colorado :angry: (I later found out this is OK @ higher elevations). I do have the light, and intermittent bearing knock, but it is not loud. We have to use that *(%^@@#* reformulated gas also!

Smitty

Changing thread subject some, but which model B-stones do you have? I have the H/Ls and find them to be *much* better tires for rain, traction, wear, and ride that the Firestones. I had a hard time deciding on these or the A/Ts, and even BFGs. I mostly do city/highway, and some rutted 2-track here in MI.

Thanks

Daryl

chevy4x4trucks · November 15, 2001

Mine is a ticking type sound that you can hear at idle. If I pull up next to something such as a building for sound to reflect, I can hear it w/ the window down. Same thing on the freeway when they had the cement barricades up, I could hear it when accelerating. The dealer is deaf to it, they claim they can't hear it.

GreenRado · November 15, 2001

Yeah, that's exactly what mine does, but not all the time - wierd.

Thought I read somewhere that GM officially reported they "tightened" the bearing clearances for the '01 model year on the 4.8, 5.3, and 6.0, and they think this is selling point!?

I guess mine is not really loud enough to get upset about, so I'll deal w/ it for now.

Thanks

alsz71 · November 17, 2001

Mine does this too but I tend to descibe it not as a ping or a knock its more like the sound of a valve tick or a sound very similar to the noise you get when your running headers and one is leaking. I'm going to take it to the dealer today and see what they tell me.

sonjaab · November 17, 2001

Guys, The lifter tick you hear is not valve adjustment.

It is the fuel running thru the injector lines. I took

mine in for cold start knock and what i thought

was lifter tap. Mechanic came out with a stethoscope

let me hear myself. As far as the cold start knock

you all get the same story as I have........Geo

02Blue · November 17, 2001

I don't have this problem with the 4.8L, now at about 2K miles, but was just wondering...

Did you guys have the problem with a completely stock engine?

I was just wondering how much it really messes with the computer when the intake and exhaust flow is modified. Or, how much it messes with the oil flow when a non-stock filter and/or oil (synthetic) is used. Even if an aftermarket chip was added to compensate for the mods, I wonder if their parameters are compatable with all sensor inputs and are their chips as well engineered as the original. I even wonder if you tried putting it all back to stock, could you expect to have a good baseline or is there some posibble permanent damage done over time?

I agree that running a higher than recommended octane fuel will cause quicker carbon buildup in a stock engine.