[steve25]

I wonder if what your hearing wrist pin slap?

At low rpm you will hear a double slap, once when the piston reaches TDC and then again when the cylinder fires, and the sound tends to get so fast with increased rpm that it seams to go away.

To prove this out If you pull the plugs one at a time at idle this noise will go away by 50%, and that’s enough to nail it down to a wrist pin issue.

[TRADERMIKE 2012]

Originally Posted by steve25

I wonder if what your hearing wrist pin slap?

At low rpm you will hear a double slap, once when the piston reaches TDC and then again when the cylinder fires, and the sound tends to get so fast with increased rpm that it seems to go away.

To prove this out If you pull the plugs one at a time at idle this noise will go away by 50%, and that’s enough to nail it down to a wrist pin issue.

This latest noise is from 1000-2000 RPM, when I am stopped and I rev. it up, I can hear it, then it disappears above that and returns as the RPM falls back to idle, I don't hear it at idle, which in park is 650-700 RPM. Then when I take off, I hear it from 1000-2000 RPM and under load it disapears as I accelerate.

I can't discount the recent Head job that these 670 "D"-port Heads have just received. What kind of a problem could the Head Mechanic have caused to manifest my current noise? Rattling Valve stems, for lack of using Valve Guides, down the Valve stem hole? Just a thought for the people who think that I answer my own queries.

By the way I can try your test once I get it running.

It looks like this weekend the Oil pan is coming off and the bottom end gets an inspection.