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Accurate/reliable way to detect engine ping?
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Author:  Fab64 [ Sat Dec 17, 2011 5:53 pm ]
Post subject:  Accurate/reliable way to detect engine ping?
Hi all,

This may be a stupid question, but is there a better way to detect engine ping than to try listening for it over the combination of engine & road noise, rattles and wind howling around the square corners as my A-body plows through the air? Seriously, is there an instrument that can accurately detect this? Could one possibly run a tube from under hood into the passenger compartment - sort of like a stethoscope? I do know what ping sounds like, and I'm trying to make sure I don't have any as I try various timing advance settings. It's just very difficult to hear anything from inside. As always, advice and opinions are much appreciated. Thanks.

Roger
Author:  ceej [ Sat Dec 17, 2011 9:15 pm ]
Post subject: 
This is pure conjecture, as I am not sure how to use the information:

Perhaps a knock sensor could be installed.
The cars of today run knock sensors so they can vary tuning parameters.
Application would be the trick. I'm not sure how you would get the information from the sensor to some useful interface.
Maybe some of our ASE members can come up with something.
Alternately, what happens to EGT's when detonation occurs? That may be a useful tool with easier application to our older, non-computerized cars.

2¢

CJ
Author:  Sam Powell [ Sun Dec 18, 2011 5:40 am ]
Post subject: 
I have a knock sensor and gauge from Casper (correction, Jasper) electronics. It uses the knock sensor for a Buick Grand National. This seems to work OK. I say seems, because there is still the concern that there may be knock that is not registered by the gauge, nor can be heard audibly. I have pretty good ears, being a piano tuner by trade, and it seems to my ears that the gauge is doing a good job of of reporting what actually happens.

You must drill a hole in the block down under the intake manifold, well below the cylinder skirts. If you decide to do this, I will give you exact coordinates to work from. When I did mine, I had an engine apart to check, so knew where to drill.

The EGT, or exhaust gas temperature thing is actually the way to set your af ratio. But, timing must be coordinated with this. So you are kind of back to knowing when pre-ignition happens.

Here is the ideal tune:

1.Air fuel ratio that yields EGT's 50 degrees less than the peak temp. Lean it out until EGT peaks, and then back it off 50 degrees from there.

2. Timing advanced under steady load until HP peaks. When it starts to fall off, back it off a few degrees. This requires a dyno to do correctly. However, a sensitive driver can get in the ball park. There are guys out there like Lou Madsen who seem to be able to get terrific results just by feel, and seat-of-the-pants tuning. There is much excellent info on the forum about timing curves with a distributor.

Sam
Author:  fzmax [ Sun Dec 18, 2011 6:52 am ]
Post subject: 
Can't you replace the coolant drain plug with a knock sensor?
Author:  SlantSixDan [ Sun Dec 18, 2011 11:13 am ]
Post subject: 
See thread here
Author:  Fab64 [ Sun Dec 18, 2011 12:13 pm ]
Post subject: 
Thanks for all the replies, and for the discussion link, Dan. It's always good to get feedback. As far as valve train clatter, I'm not even sure what that would sound like. With some cars I've had in the past, it was very easy to hear any pinging. Unfortunately, not so with my Barracuda. In any case, I may experiment with running a hose under the hood, and see if I can hear anything while driving.
Author:  Matt Cramer [ Mon Dec 19, 2011 8:45 am ]
Post subject: 
We use one of these for dyno tuning cars when we expect knock to be a problem:

http://www.phormula.co.uk/KnockAnalyserPro.aspx

Basically, it's an electronic version of the stethescope, with some built in filtering. It's a good quality piece.
Author:  Fab64 [ Mon Dec 19, 2011 9:14 am ]
Post subject: 
Quote:
We use one of these for dyno tuning cars when we expect knock to be a problem:

http://www.phormula.co.uk/KnockAnalyserPro.aspx

Basically, it's an electronic version of the stethescope, with some built in filtering. It's a good quality piece.
Thanks, Matt. That's kind of what I had in mind, only on a slightly less expensive scale. Cool design, and nice to know the principal works. Unfortunately, a bit out of reach for the weekend hobbyist. 270 pounds = $420 US :shock:
Author:  DadTruck [ Fri Dec 23, 2011 9:23 am ]
Post subject: 
tracked down what Sam P was speaking to

it is from Casper Electronics
here is a link from some toyota guys going through the process,,
http://oldschool.supracentral.com/htm/ks_mon.htm

Sam, any tips for the slant six crowd?


and here is an interesting internet article on engine knock
http://www.zhome.com/ZCMnL/PICS/detonat ... ation.html

thanks
DT
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