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I need some help, I have a dead cylinder on my mach1. I have replaced the plugs,wires,cap,rotor and valve springs nothing has helped. checked the compression at 150psi. Checked to see if it possibly bent a pushrod both straight valves open normally so now I'm lost.... I did hear something make a metallic "pop" noise just a few days before it started missing. Any thoughts??
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Sounds like you have covered the bases - I don't know. I'll have to mull that one over for a bit.
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Sounds like you have gone through the troubleshooting very well. I know you replaced the wires, plugs, etc, but just curious, did you verify that you are getting spark to the cylinder. An easy way to check the plug wire is to hook a timing light up to that specific wire and see if you get the timing light to function. A cracked spark plug insulator could also be a problem, but you have new plugs! Double check your firing order too. Anyway good luck and I hope it turns out to be something simple!
Posts: 98
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I did use a timing light to check that cylinder and it was firing, I pulled the plug wire while it was running it did not change the way it runs so I pulled no. 6 it stumbles pull no. 8 it stumbles but no change on no.7. My concern is that metallic "pop" noise I heard, that confusses me because it does not smoke, there is no coolant in the oil, nor oil in the coolant. With that said: that rules out a broken rings or piston and only leaves the valves or valves seats. Is it possible that it cracked a valve seat?
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Valve seat shouldn't be a problem, since you say you have 150psi of compression. You have to have 3 things to make an engine run. Fuel/ air, compression, spark, Is a spark plug cracked as someone else mentioned, has something blocked the intake port. bad plug could have trouble firing under compression. Keep looking. JTS 71 Mach1
Posts: 98
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It turns out that the 2bbl carb was not working right so I rebuilt the edelbrock and put it back on......no more problem,who'd a thought?
Posts: 3,119
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Yeah that seems a little crazy, that a dirty carb was causing a dead cyl? Obviously it was starving that cylinder. Glad to hear you got it fixed. JTS 71 Mach1
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