mdj21

does anybody know where i can find the components to build this knock sensor that Twin_Turbo describes here:

http://forums.corvetteforum.com/show...t=knock+sensor

i was leaning towards the first one because it sounds like it would be easier to do.

i checked NAPA for sensors for 82 corvette and came up blank.

is there some other name that these parts go by other than "knock"?

thanks,

Mike.

mdj21

stupid eyes.....

picked chevette in stead of corvette.....

wow, $100 for a detonation sensor. maybe i should get one from the junk yards. is a detonation sensor something that is likely to be bad on a junker vette?

what about the ESC module? still can't find one of those.

comp

Hmmmmmm

Twin_Turbo

ESC module: yours for only 7.99$!!!!
http://cgi.ebay.com/ebaymotors/85-92...QQcmdZViewItem

These are the nicest ones to use as you can just use the female plug and cut the wires you don't need or just use some amp connectors, the earlier ones have edge card connectors requiring the use of the edge card connector or soldering.



these are also from a roller motor which means they have an ignore circuit for those kinds of noises, stick a roller or a gear drive in an engine equipped w/ the early ESC and it may go berserk.

Twin_Turbo

oh, the knock sensor..100$ wow!
Get the one w/ this type of connector, not the earlier w/ a little metal pin/tube that sticks out and uses a rubber block connector w/ metal retainer clip.

http://cgi.ebay.com/ebaymotors/TBI-T...QQcmdZViewItem



and use this type of sensor:

http://cgi.ebay.com/ebaymotors/85-89...QQcmdZViewItem

mdj21

aahhhhhh.... ebay.... i should have thought of that.....

so it's also called a spark module?

is that the detonation sensor mounted low on the block between the 2nd and 3rd main bearings?

is that typically where they are mounted?

is getting this sensor from a junk yard a good idea? not too thrilled with paying NAPA $100 for one. or is ebay a better choice than junk yard...

Twin_Turbo

yea it's the same but be aware that the module in the hei distributor is not the same deal

Yea the sensor is usually mounted in one of the block drain holes, they don't go bad very often so one you get from the junkyard should be fine

JoeRags

interesting....

stickboy

I bought a sensor/harness from Accel. Looks like I overpaid and on top of that I had to cut of the plug that was supposed to connect to Accel's DFI harness because they had two different style connectors

mdj21

Thanks, Twin Turbo.

i've got side pipes and the glass packs are pretty shot so she is plenty loud

i want to set up my timing as Lars describes in his paper, but got nervious about being able to hear the detonation over my pipes when i read that other thread about being able to hear it or not.

is that firebird ESC module going to have the same pin-out you described previously or am i going to have to hunt down that information elsewhere?

this is starting to look more like a project i can afford. call it cheap insurance.

thanks again,

Mike.

mdj21

last question....

are any of these sensors going to work or should i just try to pull one from an early 80's vette?

http://cgi.ebay.com/ebaymotors/85-89...56238002QQrdZ1

http://cgi.ebay.com/ebaymotors/96-Co...56455623QQrdZ1

http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWA%3AIT

thanks,

Mike.

Twin_Turbo

The difference is the sensing frequency, much like a tuning fork. They have a little piëzo-electric crystal that produces a tiny voltage (<1 V) when in "tune" with the sensing frequency. It's nothing more than a microphone. So, get a sensor from an engine that is as close to what you're using as possible. The detonation may travel through a V6 casting in a different frequency than in a V8, so an L98 or LT1 should work. I wouldn't use the V6 one.

mdj21

thanks again....

69427

The plastic housing (Half Function ESC) modules like pictured above are the way to go if you want to do some spark curve/knock intensity monitoring. Please be advised that they come in many calibrations and center frequencies. I don't know the calibration details of the module above, but if you're on your own in a junk yard try to find one off an early to mid 80's SBC, as they are more likely to be calibrated (filter/freq response) for an engine similar to yours. You also ought to be able to find a sensor off a junk vehicle if you look around. The lower frequency sensors had a light blue (anodizing?) color around the connector plastic end. Also measure the resistance from the connector to the threads. It should be around 100kOhms. Later sensors generally have a 4kOhm resistor inside it. You don't really want to have to use those sensors with the older modules. The lower resistance will kill most of the signal, and you'll possibly need some reasonably heavy knock to trigger the filtering in the module.
Good luck, and keep asking questions if you run into problems.