Best ways to attack knock?

[alexiskai]

I'd like to solicit suggestions for good ways to combat knocking in high-mileage engines, in my car as well as general principles. We have a '90 Mazda Protege with 180,000 miles. It had very little maintenance until just recently; frankly I'm surprised it works as well as it does. It knocks, and it knocks more when accelerating. It knocks a lot with 87 (the original requirement), some with 89, and little/none with 93. We know it leaks oil and the knock may be caused by oil leaking into the cylinder, but there's no white smoke, so I'm not sure. I am on the first phase of a double-whammy Auto-RX leak treatment.

I'm open to anything that doesn't require taking the engine apart.

 

[wulimaster]

I had the same problems with my toy 4x4 truck. I put in a cleaning dose of Amsoil PI and the knocking (pinging, detonation) went away by the end of a tankful of gas.

 

[Patman]

There are a few things you can do, cleaning out the combustion chamber is the biggest one though. Many guys swear by Seafoam, it cleans it out fast. Although Schaeffer's Neutra or Amsoil's PI in your gas tank for a few tankfuls would probably clean just as well.

You're also on the right track by using Auto-rx, because if you can keep the excess oil out of the combustion chamber then the knocking will go down.

A colder spark plug will also help, but be warned that it will foul easier too.

 

[JohnBrowning]

If you are sure that the knock is det. related I would de-carbon the pistons. I would remove the heads and do this. If that is not an option for you try this.

I would squirt 3-4 onces of LC into each cylinder. Then I would run a good fuel cleaning additive like Fuel Power, Nuetr 131, Redline, Amsoil Quick shot...... I would run 3-4 bottle through it over the course of a month!

I have to admitt that I have not seen a fuel injected vechile have carbon related knocking as sever as your application. This tpe of carbon problem is normaly associated with older carberated engines.