CSpringer

Wanted to give a update on the project. Put the head back on and made the adjustment to the solid tappets. Still had the light knocking and lower oil pressure, little to none at idle. Decided to remove the pan and found one of the oil plugs (from the crank) laying in the bottom of the pan (inch and 7/8 plug). Given the oil circulation path I am trying to decide if I rebuild the motor again (rebuilt by the previous owner 5 years ago) or if I inspect the connecting rod bearings (reinstall the crank plug, however that is done) and put it back together. At least the problem has been found.

So, I adjusted all the solid lifters and applied a significant amount of penetrating oil to assure the lifters were operating smooth. I re-assembled the motor and the knocking was gone for about 50 miles, now I am back with the same knock on the drivers side third cylinder back (same as the original location). I plan to remove the head this weekend to see if the head gasket is torn or if I have a broken valve. I did notice (what appeared to be) back pressure from he intake manifold ports on that cylinder, any ideas on what could cause that issue?

Larry, You are correct. A few more facts, while few miles were put on the engine after rebuild (around 5k) the rebuild occurred in 2014. Notes indicate the cam was sent to the cam doctor, I can only assume the doctor was licensed to grind a cam. My understanding is the cam was milled to be similar to the earlier v-12 cams. I have noticed a bit of a visual gap, the lifter drops a bit further than anticipated after the engine stops rotation (and you can hear a bit of a pop) it was recommended I go with a .010 gap all around to reduce drop and noise. I am going to give it a shot. Short

Thanks for the information Ken, and nice car!

Just purchased a 1940 Lincoln Zephyr. I noticed a distinct light knocking in the engine. I contacted the machine shop that performed a 6.6K rebuild for the previous owner, only 4K miles ago. I discovered the hydrolic lifters were converted to solid adjustable, he did not have very much additional information on the rebuild. This weekend I pulled the Edmunds Custom intake and took a look, nothing broken, one of the solid lifter adjusters was very loose and far too easy to adjust, I plan to use green locktite to resolve, recommendation from other post. I adjusted the lifters to intake .010-