I have a question about detonation….how does a weekend mechanic like myself absolutely know when an engine is detonating? Is it the same as what others call “pinging”?? I know on my original L69 CCC system, I had a “knock sensor” that told the computer to back off the timing (I assume) , but I no longer run the CCC system.

I’m almost ready to install my engine with an Edelbrock E-force blower on it, so I need to get this straight in my head. I’ve read that detonation will kill an engine pretty quickly if not corrected, esp. with a blower. I also purchased the recommended universal MSD boost retard box that I hope to hook up with this Accell street billet distributor I have. But that’ll be useless unless I know it’s detonating…..how do you blower guys tell?
Any help appreciated. Thanks in advance.

 

Sounds like marbles clinging around in your cylinder. Short of a sensor, you cant really tell.

 

Detonation is pretty easy to hear.

It's like when you are returning your empty pop bottles to the recycler, and you've got $10 worth of bottles/cans in your trunk, and you drive over some bad roads. It sounds EXACTLY like that! Or like somebody threw marbles in your gas tank (if you can imagine that...). Rattle-rattle-rattle.

Mild detonation is harder to hear.

If your engine detonates when under severe load, your exhuast might drown it out, and then it's catastrophic. But mild detonation (like running 87 octane in a high compression engine, heavy load, up a hill, top gear, hot day) that'll just be a good warning sign... It won't leave a crater in the ground.

You can buy a knock sensor though. I'm not sure if you can use it "stand-alone", ie wire it up to an LED or something, then just watch it and see if it lights up? Seems like something someone would have invented and posted a wiring diagram for on the internet somewhere...
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Yes, google "stand alone knock sensor wiring". I just looked at the first three links there. "knock link" is one brand of gizmo. Or you can just read what DIY'ers have done...

 

OK - sounds like "pinging" then to me...I know what that sounds like already then. But I have only noticed it on cars with a relatively quiet exhaust...I think it'll be difficult to pick it out over a car with headers - unless it's severe.

Thanks again guys, and Sonix, you've been a great help!! I'll "google" around then and see what's out there.

 

Confused1, another way to tell and IMO the best way to tell is plug reading. I've learned how to really be able to read more into the performance of my engine with that. 2 Great articles I found here by another member are:

http://www.4secondsflat.com/Spark_plug_reading.html

http://www.dragstuff.com/techarticle...ead-plugs.html

I'm in the boat of a 383 with hooker LT's and a blower. There is almost no way I'm going to hear audible pinging over my setup. SO, I can either rely on my laptop while datalogging or plug read. You might not be going the custom tune route so therefore wouldn't have a laptop while you're driving. Relying on and learning how to plug read isn't a bad idea.

 

Hey thx AC!..... Great links! I've always heard plug reading is a great way to see how an engine is really running. Bookmarked both of them!

...Nice ride you have too!

 

Knock sensors are cheap, and I got an LED gauge for around 30 bucks off ebay. Easy to wire up, and its realtime. If you use a BTM, you can run on the edge for max power. All from the seat, without lugging a laptop around.

 

Thx for the info Batass but again, my car is no more complicated than a '62 Impala....I have the original CCC computer,sensors,and CCC harness hanging on my garage wall and it'll stay there since I can't adapt it to work with my setup. So a laptop computer would be useless anyway.

So how would the wiring route? Is the LED and the sensor directly wired or not? I'll need to look into it...

EDIT...I took a quick look at my cheap Haynes manual, and it looks like the sensor gets connected to a ESC module, then to a spark retard connection on the factory CCC computer. So it seems like I'll need some type of ESC module (or a transducer of some kind) that will convert the signal from the sensor to a voltage that will light up, say - an LED display right?

 

The one I have is just basically three wires. Power, signal from knock sensor and ground. I dont have it hooked up yet, so I'm not sure how well it works.

There are also grand national? gauges that use a dial. They are around 80 bucks I think.

 

Which one do you have? I searched Ebay, and only seen one from this guy in Vilnius, Lithuania for a cost of 49.98 plus shipping, but it seems shady to me....just his description kinda scares me:
-And every one I could find for Buick Grand nationals at that price are for the sensor only.

 

Yep thats the one I have, little black box with a couple lights. It used to be less. I havent hooked it up yet, but his reviews were good I think. Its a very simple system to detect knock.

Msd also has one, but its pricey as you could expect.

 

I just checked, and you're right - good reviews. It doesn't show the actual sensor that goes on the engine end, just the dash box. Do you just run a stock knock sensor (I have one), or does it come with one already - and what type? I'm thinking about gettin one.

 

It doesnt come with the sensor. As far as I know, you should be able to run the stock one. It has an adjustment for sensitivity so you can "tune out" false noisy frequencies.