Re: Ping In 359 Engine

Posted by Don Shields On 2014/5/4 21:03:09

I found the modification mentioned in the PAC thread to be somewhat ambiguous, so I sent the author of that thread an e-mail. He replied very quickly and said that he didn't do the modification himself. It was done at Ross Miller's Speedwell Garage in Parkton, MD, and the author made notes as he was told what was done to the car. I called Ross and he told me what was done.

The purpose of the modification is to slow down or limit the amount of advance available through the vacuum advance system. By limiting the advance, pre-ignition from that source would be greatly reduced if not eliminated. Since there is no tampering with the basic timing, overall engine performance wouldn't be significantly affected. By putting two flat washers inside that long hex-shaped spring housing that mounts to the diaphragm housing, both the spring and the diaphragm's movement is limited as is the advance available to the breaker plate inside the distributor. It's really very simple yet ingenious when you think about it; I'll refer to this modification as the Miller Method since it's Ross' idea. Ross also said that it's very important to set the spark timing at zero, or TDC; these engines won't tolerate an advanced setting.

The thread author is a real gentleman, sharing his experience very freely. He reported that the modification hasn't stopped the pinging entirely. In his opinion, Packard simply pushed the engine past its limits and there is no real fix for it. He said you just have to live with it and back off the accelerator when it starts to ping. In view of his experience in driving his car from New York City to San Francisco, I'd say his counsel should be heeded. If you're going to "ask the man who owns one" about this problem, he's the one to ask. So unless someone here expresses a good reason not to do this, I'm going to employ the Miller Method on my car.