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Engine Knock sensor

M

mgms_1968

Guest
Hi all


Does anyone know of an engine knock snesor that I can get to work on my 1968 vette.

Ideally I would like to have one that will allow me to automatically reduce my ignition timing when engine knock is sensed.

Has anyone used an aftermarket knock sensor?

Thanks
 
Joined
Jan 1, 2002
Messages
7,246
Location
Washington, Michigan
Corvette
'67 Marina Blue Convertible
Never heard of an aftermarket knock sensor - the '68 block has no boss to mount it in anyway.
 
M

mgms_1968

Guest
The block is not the original block. The engine is a GM 350 create motor. So I think there is one on the block. Does anyone know how to tell if the block has a provision for a knock sensor?

The reason I am asking this is that my engine has a supercharger and I am concerned about engine knock (ie preignition).

Thanks
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
Mgms,

There is a problem with most knock systems. On a modified car with headers, roller rocker arms, higher lift cams, etc. etc. etc. you tend to get noise in the engine that is not common to a standard stock unit. This background noise will cause the knock sensor to send false signals. It is almost impossible to get one to be sensative enough to pick up spark knock, but dull enough to ignore all the other back ground noise.

My 90 vette has a hard time telling the difference between spark knock and noise from the ZF trans, sometimes causing a loss in power during take off, etc.


In my opinion from my experience, this is why the majority, if not all of aftermarket ignition control devices don't use a knock sensor, but tend to use a reference signal from the boost, or drop in vacuum to automatically retard based upon your program input.


Might be something fun to play with. You have me wondering now, it a late model HEI could be installed with a ECM from say a 1990 chevy truck, and a knock sensor. Then all other inputs just snipped out of the harness. The question is, could that HEI with ESC run as a stand alone?
 

Stingray6974

Well-known member
Joined
Oct 12, 2000
Messages
494
Location
Garland,Texas
Chris,
Chevrolet already tried that. On the 81-84 1/2 ton pickups. The system only controlled timing and used just a knock sensor. Only problem was the ECM couldn't tell the difference between engine ping and fuel pump noise. All chevy V8 knock sensors are screwed into the block coolant drain on the right side of the engine. Chevrolet's cure: Bypass and disable the ESC system.
Mike
 

Evolution1980

Well-known member
Administrator
Joined
Feb 25, 2002
Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
MGMS_1968,

If you want to be able to manually control your timing while you drive, look at Jacob's Ignition Systems. They have a fully digital ignition system that allows you to control things, such as timing, right from your dash in real time.

http://www.jacobselectronics.com/products/timingcontrols/timing.htm

I have the base Jacobs Ignition system in my car and absolutely love it. One of the best investments I've made (second only to my engine)!
 

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