tfbrown
04-03-2001, 06:42 PM
First of all I'm not sure this is the right forum for this, but I'll give it a try....I have been getting the DIGEST version of the daily Z chat and enjoying it a lot...I tried a few posts at the bulletine board but find that it takes forever to get a reply....
I have a 73Z with an L24, all stock except for the 72 round tops, I bought it last summer and have bills to show the engine was REBUILT about 10 years and 10000 miles ago, bills say it was OVERSIZED, doesn't specify whether this refers to bearings or cylinder bored out a few thou though. Anyway it runs like a PoS, lumpy idle and lumpy non linear response to throttle (feels like 1 or 2 aren't firing, though I know they are). I have rebuilt the carbs (with ZTHERAPY'S help), put in a new cap/rotor/points (20 thou), set the timing, new plugs/wires etc....when I set the valve lash I found all exhaust valves set to 10 thou (cold) and all intakes at 00 thou (cold(yup...no lash)), I don't know what the previous owner was thinking but...... I was wondering if this is the cause of my rough running.
Noteworthy is the fact that #3 and #4 spark plugs are oily, not fouled but definately too wayyyyy too oily. I took an old spark plug, knocked out the center and added an air nipple to check for leaks past the rings or valves, THE PROBLEM; when I pressurize the cylinder with 100 psi I find it nearly impossible to hold the cam (whole engine really) in place at/near TDC for the cylinder I'm checking as it wants to drive it downwards. ALSO with the help of a extension bar on my 1/2" socket I am able to hold against the pressure (19mm socket on cam nut at front of engine) but can HEAR AIR RUSHING OUT OF THE CYLINDER. I don't know where its going but I can hear it (a steady medium hissssssssss).......WHAT NOW....HELP PLEASE.
TIA
Tim
I have a 73Z with an L24, all stock except for the 72 round tops, I bought it last summer and have bills to show the engine was REBUILT about 10 years and 10000 miles ago, bills say it was OVERSIZED, doesn't specify whether this refers to bearings or cylinder bored out a few thou though. Anyway it runs like a PoS, lumpy idle and lumpy non linear response to throttle (feels like 1 or 2 aren't firing, though I know they are). I have rebuilt the carbs (with ZTHERAPY'S help), put in a new cap/rotor/points (20 thou), set the timing, new plugs/wires etc....when I set the valve lash I found all exhaust valves set to 10 thou (cold) and all intakes at 00 thou (cold(yup...no lash)), I don't know what the previous owner was thinking but...... I was wondering if this is the cause of my rough running.
Noteworthy is the fact that #3 and #4 spark plugs are oily, not fouled but definately too wayyyyy too oily. I took an old spark plug, knocked out the center and added an air nipple to check for leaks past the rings or valves, THE PROBLEM; when I pressurize the cylinder with 100 psi I find it nearly impossible to hold the cam (whole engine really) in place at/near TDC for the cylinder I'm checking as it wants to drive it downwards. ALSO with the help of a extension bar on my 1/2" socket I am able to hold against the pressure (19mm socket on cam nut at front of engine) but can HEAR AIR RUSHING OUT OF THE CYLINDER. I don't know where its going but I can hear it (a steady medium hissssssssss).......WHAT NOW....HELP PLEASE.
TIA
Tim