I pushed the car too much yesterday coming back from a car show. There's a good stretch of highway 7 miles from home and I usually clean the plugs and carbon deposits in general by pushing the motor a bit. Nothing serious, just accelerating from 70 to 100 with the O/D on and revs not going above 4,200. Done it plenty of times in the 11 years I'vehad the car. Now 72K miles on the odo..
As I got to the stop light, I noticed it idled a bit rough and when I took-off I felt as if there were only 5 cylinders pulling the car. I limped it home and waited until it cooled-off a bit.
Checked if there was spark at every cyl by pulling the wires one a time while at idle and #4 didn't make a difference. I checked for compression and when I pulled #4 plug it looked like the pictures I included. All the others were ash in color and looking good. When I checked for compression, the others were at 120 lbs, but #4 was at zero,zilch, nada!
Took the valve cover off and checked the valve clearance on 7 & 8, good at 0.010".
Last night I ordered an endoscope camera for the iPhone which should arrive tomorrow PM. I'm hoping it's just a stuck valve. Maybe looking inside will confirm my theory. I will also adapt the compressor hose to push some air in through the plug opening and check for air flow while the valves are closed.
Any other ideas on how to inspect the damage before I decide to pull the head? The debris found on the plug is not metal. I scraped it off after taking the pics and tried to pick it up with a magnet and nothing stuck to it. The plug also smells of gas heavily. The car never smoked on the way home, I never heard any noise coming from the engine while at speed, it holds idle, although the valve train sounds a bit louder than normal.
Any thoughts, suggestions, reprimands for going too fast on a 41 yr old car with no airbags are all welcome. B)
Many thanks,
Robert
As I got to the stop light, I noticed it idled a bit rough and when I took-off I felt as if there were only 5 cylinders pulling the car. I limped it home and waited until it cooled-off a bit.
Checked if there was spark at every cyl by pulling the wires one a time while at idle and #4 didn't make a difference. I checked for compression and when I pulled #4 plug it looked like the pictures I included. All the others were ash in color and looking good. When I checked for compression, the others were at 120 lbs, but #4 was at zero,zilch, nada!
Took the valve cover off and checked the valve clearance on 7 & 8, good at 0.010".
Last night I ordered an endoscope camera for the iPhone which should arrive tomorrow PM. I'm hoping it's just a stuck valve. Maybe looking inside will confirm my theory. I will also adapt the compressor hose to push some air in through the plug opening and check for air flow while the valves are closed.
Any other ideas on how to inspect the damage before I decide to pull the head? The debris found on the plug is not metal. I scraped it off after taking the pics and tried to pick it up with a magnet and nothing stuck to it. The plug also smells of gas heavily. The car never smoked on the way home, I never heard any noise coming from the engine while at speed, it holds idle, although the valve train sounds a bit louder than normal.
Any thoughts, suggestions, reprimands for going too fast on a 41 yr old car with no airbags are all welcome. B)
Many thanks,
Robert
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