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-   -   What does pinging sound like? (http://forums.pelicanparts.com/porsche-911-technical-forum/536579-what-does-pinging-sound-like.html)

coglin 04-13-2010 08:56 AM

What does pinging sound like?
 
I am trying to figure out whether my 1979 SC is actually pinging but cannot identify it among all the various noises back there. Can anyone offer advice on how I can identify a pinging sound?

Mainly: is it fairly obvious when these cars ping or can one miss it entirely?

Best I can do to describe what I hear that I suspect is possible pinging is: a medium-high pitch groan - around 3000 RPM, and sometimes below; I know, that helps a lot...:rolleyes:

Thanks for the help.

Steve@Rennsport 04-13-2010 09:28 AM

Pinging sounds like a rattle (or knock) and generally happens under load. If you hear what you think may be pinging, lift your foot off the throttle to see if it goes away as thats a sure-fire way to confirm.

Groaning?? I'd need a LOT more information such as RPM range, throttle position, engine temperature to offer a guess.

DARISC 04-13-2010 09:43 AM

Quote:

Originally Posted by Steve@Rennsport (Post 5293024)
Pinging sounds like a rattle (or knock)...

Or a ping. :D

I once had a '71 240Z with a 280Z motor running 2 carbs, water injection and a turbo (w/o intercooler)...but not for long. After several hours of fun, it began losing power and I barely made it back to my mech. Detonation burned holes in the pistons and fried the valves - never heard the slightest sound when it was happening. :(

coglin 04-13-2010 09:50 AM

I wouldn't describe what I hear as a knock or a ping, but a "rattle" comes close. I get it over a narror RPM range, 3,000 to 3,200. I get a slightly different sound below 3,000; also a rattle-type sound; but I've been told that's just the CIS injectors . . . :confused:

I generally set the timing to the low end of spec, for the record.

Thanks

coglin 04-13-2010 11:06 AM

One other thing:

How loud is pinging? Should one have to listen for it to identify it or is it loud enough to be obviously apparent?

Many thanks.

GaryR 04-13-2010 11:11 AM

Sounds like..... $$$$$$$$$$$$$$$ going down a drain.

kenikh 04-13-2010 11:34 AM

Think of the sound a stack if fine china dinner plates makes when you rattle them.

DARISC 04-13-2010 12:14 PM

Quote:

Originally Posted by coglin (Post 5293204)
One other thing:

How loud is pinging? Should one have to listen for it to identify it or is it loud enough to be obviously apparent?

Many thanks.

As I related in my post #3, pinging (which is detonation that is audible) can be totally inaudible and still destroy your motor, while you motor, merrily along - until you don't.

kenikh 04-13-2010 12:17 PM

Sometimes you can hear it, sometimes you can't - regardless, always BAD.

jtfreels 04-13-2010 12:47 PM

Would it be reasonable to assume that you would get the pinging in any gear as you go through the 3000RPM range?

I ask because at one point I had a pinging type noise , under load but only in second and not all the time.

Jay

DARISC 04-13-2010 01:04 PM

Quote:

Originally Posted by jtfreels (Post 5293411)
Would it be reasonable to assume that you would get the pinging in any gear as you go through the 3000RPM range?

Not really. What gear you're in doesn't matter; it's the load on the engine, i.e. you might be able to cruise on the level (in any gear) without pinging at 3k, but could start pinging when you have to give it more gas to maintain that rpm level when level changes to uphill (more load).

Jgordon 04-13-2010 01:38 PM

When I'm in too high a gear in either the 911 or the toyota (1985, carbed) and I put my foot down, I get a rattling sound. I've wondered if that's pinging before. When I let my foot up, it goes away. I can also reduce it or get it to go away by letting up slightly, and "matching" the depression of the gas pedal to the rpms. if that makes sense.

Any thoughts? Just sounds like gravel rattling around.

tcar 04-13-2010 01:50 PM

Quote:

Originally Posted by Jgordon (Post 5293494)
When I'm in too high a gear in either the 911 or the toyota (1985, carbed) and I put my foot down, I get a rattling sound.

That is classic pinging.


The Brits say "pinking" which I think describes the sound better.

It can be fairly loud, almost inaudible or totally inaudible - all can damage things.

Don't ever lug the engine (even a Toyota), keep your revs up.

Use proper octane fuel.

Hot operating temps can make it worse.

Doing it deliberately is a very bad idea - it can and does break things inside the motor.

Steve@Rennsport 04-13-2010 02:56 PM

Quote:

Originally Posted by coglin (Post 5293204)
One other thing:

How loud is pinging? Should one have to listen for it to identify it or is it loud enough to be obviously apparent?

Many thanks.

If you can hear it over the normal cacophany of the air-cooled engine, its NOT good at all. I tell my clients to NEVER use their ears as the defacto knock-sensors, otherwise they may be spending a great deal of money to fix things.

Back off the ignition timing several degrees to ensure its not detonation. I'd also recommend finding an experienced 911 professional to help diagnose this.

ClickClickBoom 04-13-2010 03:13 PM

Sounds like a shovel full of gravel poured onto a galvanized metal roof.
eric

Jim2 04-13-2010 03:56 PM

"What does pinging sound like?"

click click BOOM!

Well, maybe with a few more clicks in there.

JFairman 04-13-2010 05:02 PM

Describing the sound of trace pinging or all out steady knocking detonation is so subjective the descriptions will be all over the place and possibly confuse you more.

I'd describe trace ping or pinking as random occasional very short duration high pitched tink or tick like sounds as the engine passes through it's torque curve at or near full throttle.

To describe how loud it is depends on if the engine area sound pad is in place and if the interior sound pad under the the rear deck vinyl is still there. Some people remove those to reduce weight. The one above the motor removes itself after 20 years.

And you have to have the windows up and sunroof closed to reduce wind noise and still have a muffler on the car to hear it.
Still it is subjective...

If you don't know what it sounds like have someone ride in the car or drive it that does know the sound.

Sometimes with the crappy low octane low detergent gas we get today you can even get some pinging at medium speed low power small throttle openings if you have alot of ignition advance and carbon buildup in the combustion chambers.

Trace pinging or pinking at low power small throttle openings and rpms like that is harmless.

If you have some of that going on you need to take out and run it fast for a while and blow some of the carbon buildup out of the combustian chambers, back side of the intake valves and both valve seats, and exhaust ports.

Only high power continuos detonation will cause damage and it's sometimes way overrated on these forums. The piston rings are not made of glass like some may lead you to think but it's good to be on the safe side.

Some people will not agree with this and thats fine with me.
Being a car guy and self taught musician that learned totally by ear is very good ear training...

steely 04-13-2010 06:37 PM

in my best Sean Connery voice:

"Shend one ping, one ping only Vasili"

sorry, I couldn't resist.

To get serious, I thought pinging was the same as knocking/dieseling?

Gene Smith 04-13-2010 07:42 PM

Too bad about the Z car...
 
Welcome to the Dark Side.

My Z car used to eat 911s for breakfast- Until rust ate her.

A $69.95 "Thunderbird Header" and 2.5 exhaust was what we used to call the "Sex Change"!

7 main bearings and no rev limiter= bullet-proof FUN!

I still remember chasing those six universal joints until I just changed them ALL.

http://forums.pelicanparts.com/uploa...1271216517.jpg

DARISC 04-13-2010 08:30 PM

Quote:

Originally Posted by Gene Smith (Post 5294190)
My Z car used to eat 911s for breakfast- Until rust ate her.
http://forums.pelicanparts.com/uploa...1271216517.jpg

Beauty! I've owned three. 2355 lb of beautifully styled automotive art. I miss 'em all! :D


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