Detonation????

[bohunk60]

After rebuilding my Volvo 3.0L GL/SX and getting my timing adjusted, I am getting what sounds to me like detonation knock under power. I've been told detonation can have some terrible consequences to an engine. I have four plans of action and am looking for comments on them.<br /><br />1. Adding high performance octane booster to my gas.<br /><br />2. Retarding the timing some even though the base timeing is correct. (EST ignition module.)<br /><br />3. Adding a hose from the blow-by vent to the flame arrester housing in hopes to cool the igintion.<br /><br />4. Setting the carberator to a bit more rich mix.<br /><br />Finally I've been told that I may be hearing exaust excaping from the manifold gaskets which I did not replace when I first rebuilt the enginge.<br /><br />Any help is appreciated! I really don't want to burn up this engine.

 

[Juancho]

Re: Detonation????

I have heard of only two causes for detonation, bad gas or timing too advanced. I would backoff the timing a bit.

 

[akriverrat]

Re: Detonation????

1)how old is the fuel? old gas has lower octane. leaking intake gasket can lean out mixture and cause problem too.2)do it because this condition can burn pistons but try to find cause and fix it. 3)there should be a hose from valve cover crank vent to flame arrestor unless your engine has some other provision for getting fumes to intake. 4)if carb worked befor and not gummed up from sitting it should work now. float setting, high speed jets, and power valve are likely suspects if lean condition caused by carb. idle jets do little at high rpm. manifold and carb gaskets is where i would be looking if you are sure about timing.

 

[Bondo]

Re: Detonation????

Your plan sounds solid... I'd skip #1...<br />Also your reuse of gaskets Could be a major part of the problem....