I would like to know more about the symptoms of cavitation that might occur when driving. The previous thread showed this action as collapsing air bubbles- would this sudden explosion of a bubble produce an audible knock, or "crack" from the engine?

I'm still obviously worried about the cracking / pinging noises (similar to spark knock) I'm getting when running near straight Diesel. When I add more WVO, the noises go away when engine heats up, but is very severe when cold- also lots of bluish white smoke at cold idle. With straight Diesel, it's the opposite- no abnormal noises when cold, and less cold smoke, but the cracking noises become very severe when warmed up and the car is at speed. This started well before I started using WVO, but has definately gotten worse.

A Diesel-Purge cured the problem for about a day. I now add "Gunk Diesel Fuel Conditioner" to fuel as directed on the bottle- about a pint per tank full. It seems to work better than the Purge did, but still doesn't eliminate the cracking noise completely.

I am going to leave my car with a good indie in Halifax sometime in the next three weeks- I want him to check the following

-bench test the injectors, replace with rebuilts if necessary
-while injectors are out- compression test and examine pre-chambers
-check fuel vacuum with some WVO in the mix- cold and hot
-adjust valves
-check IP timing and timing chain - adjust and replace if needed.

I have no other symptoms- milage is still 25 MPG or better- no power loss, etc

Dave M.
Sackville NB Canada
1976 300D