Knocking...

[Vrotate]

My friend has a V6 Camaro that is pinging badly. The manual calls for 87 octane. I told him to put 93 in the tank, it fixed the problem.

But my question is, what causes a car to start pinging over time? Is it the timing, plug gap, knock sensor, or a combination of all?

Obviously he doesn't want to continue to put 93 in the tank... I told him to get a real car!

Thanks

Everyday Vette

 

[Ken]

Any number of things may contribute to engine knock, the most obvious being poor gasoline quality or grade.

• Engine Knock:
  When the engine is operating, an audible noise may be heard when the fuel in the cylinders is ignited too early and/or spontaneously, resulting in colliding flame fronts and shock waves which cause high thermal and mechanical stress, and can severely damage the engine.

A few things that may cause...

1. Knock:
2. A general term used to describe various noises occurring in an engine; may be used to describe noises made by loose or worn mechanical parts.
3. Preignition, or detonation.

• Preignition:
  The fuel charge being ignited before the proper time. Sometimes causes pinging or detonation. This is the combustion of the fuel-air mixture that is not a result of the spark plug's firing, but by high pressure, a flame, or a hot surface.
  
  also known as...
• Detonation:
  The action of the fuel charge firing or burning too violently, almost exploding. It sometimes results in a noise called "pinging." Detonation is caused by autoignition of the "end gas" i.e., that part of the charge not yet consumed in the normal flame-front reaction. Detonation occurs because piston motion and compression of the end gas raise its temperature and pressure to the point where the end gas autoignites. The pinging or knocking noise is the result of intense pressure waves in the charge which cause the cylinder walls to vibrate. Also called "fuel knock."
  
• Carbon Knock:
  When there is a build-up of carbon in the combustion chamber, uncontrolled ignition will take place causing a knocking noise.

Hope this helps you.

_ken

 

[Vrotate]

Knocking

Thanks Ken,

So what does he need to do? He can't keep putting 93 in it. I heard gas treatments wern't worth buying...

Vrotate

 

[Steve92LT1]

He can try and retard the timing a little bit.. it should help him out no matter what.

Also some kind of engine cleaner crap to get some of that carbon out (I've never used the stuff, but I believe carbon is his main problem)

 

[jet4rs]

So what do we do about this pinging Ken?

I've got the same problem in my Dodge Dakota V6.

Bob

 

[Jack]

Believe it or not ... they'll ping MORE when weather turns cold. I gotta stock alum head 10:1 CR V8 Lincoln that does it in cold weather but only for a minute or two after cold start. If yer pal's V6 is old ... maybe there's a buildup of carbon (Ken's carbon knock) on the piston/valve faces/combustion chambers ... this'll also cause pinging ... in any motor.
JACK:gap

 

[chevyaddict]

This is excellent information. However, what do you in the case of the newer vehicles that have their timing controlled by the computer, thus not allowing you to adjust the timing?

I have heard a trick to break loose the carbon deposits is to drop small droplets of water down the intake. Is this an old wives tale or does this work? Is this safe or harsh on the engine? If large chunks come off it would seem that could do some considerable damage. Our 84 vette likes to ping in the summer but not in the winter. Granted we only use 87 octane gas but that is mainly because we live quite a distance away from town and simply can't afford to put the good gas in it. Now, however, it is running well with no pinging at all. I doubt carbon build-up is in our motor - we (or I should say I) rag on it quite a bit. We keep all our cars overly tuned up (I am somewhat anal about that). I keep spreadsheets on all our cars so I can keep track!

 

[Steve92LT1]

There is a product called Seafoam... it is designed to clean all that carbon and crap out. I haven't used it but I heard it works good as long as you follow the directions properly.

I've heard of the water trick too... but I don't know if I would try it though. I've heard about back in the day pouring a little tranny fuild down the carb will help, but it WILL smoke like a factory until it all burns out.

On the older (pre LT1 cars) the timing is adjustable... LT1 and LS1 can't be adjusted.

 

[tkrphxr]

Knocking

You can use the water method but have to be very carful because water will not compress like air. The best way is to use a spray bottle and mist the water in a little at a time with the rpm at about 2000. Good luck Charlie

 

[Vrotate]

Knocking

His car has computer controlled timing. I guess I'll tell him to try the sea foam, and maybe 89....


Thanks for all the help

Vrotate

 

[vigman]

I use the water trick

Works ok... but has to be a FINE mist.... otherwise OH OH Bye bye motor!

I made an adaptor from the garden hose to a little drip mist sprinkler head for gardening.. works PERFECT!

I also stick a little wood wedge in the throttle linkage to keep things around 2500 rpm.


Vig!

 

[Steve92LT1]

Just curious.... but what year V6 camaro is it?

 

[elkabong]

The water trick does work. I used when I was a tune-up mechanic many years ago for a chain called Tune-Up Masters. But as mentioned in earlier posts you gotta be careful to not add too much water. I know Tune-up Masters is still around in some states. Have your buddy spend the $49 for a tune-up and let them take the liability. Just a thought.

 

[BlackNBlue95]

I've heard the water trick I think it may work.. but what we do at my shop is use a MotorVac thats the brand name.. it's pretty cool..

What it does is hook up to the fuel lines.. and on systems like our GM's that are Fuel injected they have return lines it hooks up to the pressure and return lines and you run a combo of gas and solvent through the fuel rail.. whith the car off that cleans the injectors..

Then while it's running for 15-20 minutes on that we clean the intake with a very potent solvent.. we prop the throttle plates open.. run a small tube down the intake and spray it down.. then we spray a little ont he plates and on a rag and clean the plates down so there nice and clean..

Then we start the car and run it on the motorvac (we loop the pressure line back to the return so the fuel pump, pumps back into the tank.. The motor vac has a built in pump and filter.. and we run it with the fuel/solvent mix for 1/2 hour to 45 minutes or so.. that cleans an engine up really well on older cars or with more miles you can usually notice a differance..

and how much does this cost.. my shop somewhere around 150$
hour labor plus the solvent isn't cheap..
just my two cents..
-Rick