I thought I would be making some performance improvements to this '82, 720, Z22 acquired last June by changing plugs and checking timing. MISTAKE.
It was running OK; little noisy and complete with noticeable exhaust and fuel vapors. So, I thought, let's get dirty.....tune-er-up....
Yes the old plugs looked a bit burned and oily. One insulator was loose. One had a significantly decreased gap.
Pulled them; put new NGKs BPR 5es & 6es in then discover NO notch on the main crank pulley for timing purposes. (I think this is NOT the original engine) Proceeded to find TDC@compression via the dowel -in -#1 cylinder 'method' hand cranking with a socket on the crankshaft pulley bolt and watching the distributor rotor, too. (Access very difficult, I might add) But, I was having a "Return to those Manly Younger Mechanic Days"
Long story - longer: Timing was not really out. It fired up and sounded better than before. After a few minutes I see white smoke billowing out of the tailpipe. WHAT? Must be some oil leaked from the plug sockets or something. I drove around the hood for about ten minutes, leaving a trail of white smoke in my wake. Except for the smoke, performance seemed fine...This was last night.
This morning, I started it up from cold noticing it went into high idle quicker than before and as it warmed dropped rpms and started billowing white smoke again.
In the light of the morning, I could see that this was mostly water vapor and liquid drops, i.e., coolant. NOT OVERHEATING, at least for the 20 minutes idling. Shut down. Later, colder, opened radiator cap to see horrors of horrors; verification of a coolant level drop though not much.
Why would changing out plugs result in an apparent head gasket failure? OR, an intake gasket failure? OR BOTH!
Would a compression test rule out/confirm a head gasket failure? Any advice? Thanks