so..did several WOT launches at 16.5 PSI
brought car back to garage.everything idling okay, seems fine. Vacuum 21mmHg. Nothing unusual seen.
Next day, did a bunch of stuff to install a pressure sensor on the exhaust header.
Started the car up..idles like crap. Uh oh..did I crack a piston? Vacuum still around 20 to 21mmhg..usually when I crack a piston it goes down to 18 mmhg.
Idle wanders around 1000rpm maybe +/- 100rpm..can here various pops every now and then in exhaust. Engine seems to be missing/vibrating.
Figured I must have popped a vac line off or bumped something.
Went through the usual laundry list:
-checked timing: OKAY
-checked fault codes: NONE
-checked vac lines by disconnecting and doing the ol stick-to-tounge vac test...some of them were actually leaking quite a bit and had cracks. Fixed them. Heater hose vac source line was cracked in half. Taped off. Disconnected charcoal canister system entirely and plugged TB ports.
-tested fuel reg vac line..clean as a whistle, holds vac
-pinched off PCV vac line which is clearly leaky and cracked
-checked distributor and rotor..kinda eroded but no big deal. metal vanes solidly mounted.
-put timing light on each plug wire, all seemed the same
So none of that fixed it.
Next I tried:
-taking all 4 spark plugs out..hmm #1 plug had a little puddle of I think oil in its pocket...yikes. Replaced #1 with another used plug I had laying around.
-Otherwise plugs all looked normal. None felt loose. I always torque them with a torque wrench so I have no reason to believe they would be loosen anyway.
-wiggled fuel injector plugs just in case I didnt seat them very well
Started it up..ROCK SOLID IDLE. As good as it gets basically.
VIDEO CLICK HERE
Heres a video of the fixed idle. Sorry I dont have a video of the bad idle.
So while I was typing this I forgot if the #1 plug looked weird in anyway. I went out to the garage to grab it. Hmm looks normal. I turned it over and heard a "clink"....
so how did that happen? I've never seen this before. Does that mean there was heavy detonation? Engine seems to be running great.
This is an autolite 63.