A question for the old school engineers

[Cleveland302]

I've just had a new electronic distributor fitted to the F100's old 302C to replace an older type of e/d which had failed. The engine is in good condition and uses very little oil, <500mls between oil changes. The problem I now have is that the motor now knocks, big-time, at anything more than 1/3 throttle. I know the timing is right because I watched the mechanic do it. He also adjusted the carburettor, a 600cfm Rochester. My suspicion is that he may have made the mixture to lean. Could this be my problem? I use premium ulp with an octane booster as the motor has not been modified to use ulp.The motor was rebuilt, so I'm told, with a modified cam (for towing). Given this scenario should the carburettor be adjusted to run on a "richer" setting?

 

[HDi fun]

If the timing is correct then lean running will cause this problem. You need to sort it out ASAP otherwise you're likely to burn piston crowns and valves.

It might be a case that the carb needs re-jetting rather than simply richening the mixture across the whole operating range.

 

[Cleveland302]

Thank you for the advise. I will be calling the mechanic tomorrow morning. Cheers, Cleveland.