Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Knock ?
Author Message
joe38socalif Offline
Member
***

Posts: 55
Joined: Nov 2008
Reputation: 0
Post: #1
Knock ?
What is the cause of Knock?

CALL YOU CONGRESS MEN AND OR LOCAL LEGISLATOR AND TELL THEM TO REMOVE ETHANOL FROM ARE FUEL. TELL THEM FOOD ON THE TABLES OF AMERICANS IS MORE IMPORTANT AND KILL THE ETHANOL FROM CORN DEAL. ETHANOL FROM CORN CAUSES EVERYONE TO PAY MORE FOR FOOD.
12-01-2008 01:39 PM
Find all posts by this user Quote this message in a reply
ptours99 Offline
Member
***

Posts: 162
Joined: Apr 2008
Reputation: 0
Post: #2
RE: Knock ?
it's a rod knock,usually the rod or main bearings on the crankshaft become deteriorated and break apart or the bearing spins out of its permanant location,will cause a loss in oil pressure also as an added feature.

selling an enclosure for the rear of cab semi truck 28''X20''X6'' CUSTOM MADE ALUMINUM TO HOUSE HHO GENERATORS AND INCLUDING A RESERVOIR BUBBLER AND REGULAR BUBBLR ptoures@sbcglobal.net usa only
12-01-2008 02:45 PM
Find all posts by this user Quote this message in a reply
benny Offline
Member
***

Posts: 332
Joined: Sep 2008
Reputation: 5
Post: #3
RE: Knock ?
ptours99 Wrote:it's a rod knock,usually the rod or main bearings on the crankshaft become deteriorated and break apart or the bearing spins out of its permanant location,will cause a loss in oil pressure also as an added feature.

Methinks that is a different type of 'knock' than that which knock detectors are looking for.
That type of knock is the effect caused by ignition timing being slightly too far advanced, or, in the case of injection systems, the fuel is injected too early. Fuel ignites too early, ie before the piston is at the optimum position for ignition. The expanding ignited fuel initially acts against the piston movement and produces 'knock' or vibration.. Similar effect to diesel engine knock.
Knock detector tells the ECU to retard fuel injection/ignition timing to correct/remove this effect if found.
Also now used in later model diesel engined vehicles for same reason.
(This post was last modified: 12-01-2008 03:20 PM by benny.)
12-01-2008 03:14 PM
Find all posts by this user Quote this message in a reply
colchiro Offline
Moderator
*****

Posts: 3,265
Joined: Feb 2008
Reputation: 11
Post: #4
RE: Knock ?
The short list: low octane gas, old gas, timing too far advanced, carbon deposits in the cylinder (which increases the compression).

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
(This post was last modified: 12-02-2008 04:37 AM by colchiro.)
12-01-2008 04:21 PM
Find all posts by this user Quote this message in a reply
Delray Dude Offline
Member
***

Posts: 105
Joined: Aug 2008
Reputation: 0
Post: #5
RE: Knock ?
joe38socalif Wrote:What is the cause of Knock?



Depends upon what type of knock you are asking. If it's a consistent knocking as the engine is running, it could be an engine failing as mentioned - a spun bearing will produce a rod knock. Also, over -revving a motor can get a wrist pin knock - equally not good.

If it's a sporadic knock (usually on accelerating) - that is fuel related - as in too much compression / wrong timing / too low octane, etc.

1993 Mustang LX
2.3 Liter engine
5 speed manual
8.8 GT axle with 2.71 gears
Smack Design Booster
EFIE currently set at .25
Without HHO was getting 24-25 MPG
Best result with HHO : 29.5 MPG
12-02-2008 04:23 AM
Find all posts by this user Quote this message in a reply
saltmine Offline
Member
***

Posts: 89
Joined: Aug 2008
Reputation: 0
Post: #6
RE: Knock ?
Knock, or detonation is caused by two opposing flame fronts colliding in the combustion chamber. Usually it starts when something in the chamber(s) reaches a temperature high enough to ignite the fuel. This condition is also called pre-ignition, or incipient spark knock.
Carbon build-up, high compression, poor quality fuel, and incorrect timing are all suspect in causing spark knock. It can be cured, most of the time, by changing fuel, de-carboning combustion chambers, adding octane booster, or resetting the timing. Most modern cars and trucks have "knock sensors" which allow the computer to reset the timing before spark knock becomes a problem. A knock sensor is actually a pizeoelectric microphone tuned to a selected frequency, the sound of spark knock, which can be read by the computer.
Detonation is not a good condition. Continued spark knock can damage pistons, valve faces, and eventually bearings. In a computer equipped car, the ECM will pull the timing back to address the spark knock, but remember, each degree of timing that gets retarded from optimal will cost you approximately one mile per gallon.

The good news is; HHO does have an octane boosting function. It also has a cleaning effect on the combustion chambers and through catalytic converters. Ethanol also boosts octane, but, due to it's low BTU value, requires almost twice as much to produce the same power as gasoline.
12-02-2008 07:43 AM
Find all posts by this user Quote this message in a reply
joe38socalif Offline
Member
***

Posts: 55
Joined: Nov 2008
Reputation: 0
Post: #7
RE: Knock ?
saltmine Wrote:Knock, or detonation is caused by two opposing flame fronts colliding in the combustion chamber. Usually it starts when something in the chamber(s) reaches a temperature high enough to ignite the fuel. This condition is also called pre-ignition, or incipient spark knock.
Carbon build-up, high compression, poor quality fuel, and incorrect timing are all suspect in causing spark knock. It can be cured, most of the time, by changing fuel, de-carboning combustion chambers, adding octane booster, or resetting the timing. Most modern cars and trucks have "knock sensors" which allow the computer to reset the timing before spark knock becomes a problem. A knock sensor is actually a pizeoelectric microphone tuned to a selected frequency, the sound of spark knock, which can be read by the computer.
Detonation is not a good condition. Continued spark knock can damage pistons, valve faces, and eventually bearings. In a computer equipped car, the ECM will pull the timing back to address the spark knock, but remember, each degree of timing that gets retarded from optimal will cost you approximately one mile per gallon.

The good news is; HHO does have an octane boosting function. It also has a cleaning effect on the combustion chambers and through catalytic converters. Ethanol also boosts octane, but, due to it's low BTU value, requires almost twice as much to produce the same power as gasoline.


saltmine
Thank you very much that was some good information. just what i was looking for.
Have a great Night.

CALL YOU CONGRESS MEN AND OR LOCAL LEGISLATOR AND TELL THEM TO REMOVE ETHANOL FROM ARE FUEL. TELL THEM FOOD ON THE TABLES OF AMERICANS IS MORE IMPORTANT AND KILL THE ETHANOL FROM CORN DEAL. ETHANOL FROM CORN CAUSES EVERYONE TO PAY MORE FOR FOOD.
12-02-2008 06:28 PM
Find all posts by this user Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)