<VV> Mechanical oil pressure gage failure

[Ewell Mills]

I have two cars that I have added mechanical oil pressure gages to and both have failed.  Since I had trouble on one car with the plastic 1/8" tubing breaking, I redid both cars using a one piece 1/8"/8" copper line that I was able to buy in 25' rolls.  I am now having trouble with both cars failing.  One started out by being really slow to come up to the correct pressure before completely failing.  The other car just failed suddenly. (By failure, I mean a reading of zero).  It appears that the 1/8" copper tubing is stopping up, since temporally adding both another gage, and the one up front with a short piece of tubing at the place I connect them (under the O.P. sending unit),  they work just fine.  The oil pressure pops up to what it is supposed to be immediately. The copper tubing seems to be about the same size internally as the plastic, and the outside of both definitely is.  I am thinking of using 1/4" tubing with reducers (since the Flaps that I use does not stock 3/16")  to replace it, but this seems to be extreme overkill.  Has anyone had this problem with Corvairs or otherwise.  Any ideas appreciated, on or off line.

Cecil Mills
Cocoa, Fl.