Help! Loud tick / pop only when #1 cylinder fires...
10-09-2010, 05:10 PM
#1
Help! Loud tick / pop only when #1 cylinder fires... I've had a loud tick, really more of a "pop" develop after a trip to the track. I don't think that it is metal on metal, sounds almost electrical. I have isolated it to the #1 cylinder, and what is interesting, it is completely ON or OFF depending on whether the cylinder is firing... i.e. when plug wire is on, POP POP POP, when plug wire is off... no noise... or at least not enough to detect. Also, noise fades/disappears with rpms... is the most present at idle. I don't think its a header needing tightening because the noise doesn't get louder with rpms.
What I have done so far...
change plug on #1 cylinder
ensure plug is fully and properly threaded
swap plug wires
swap coil packs
swap injectors
None of the above made a difference. Still ON / OFF if cylinder was firing or not.
Then I checked the header bolts to ensure they were tight, no issues there, headers on tight.
Then I held my breath and pulled the valve cover - fortunately didn't see any metal or evidence of damage and there was no play in the rockers, push rods, etc.
Engine is an L92 bored/stroked to 427, TFS 235 heads, cammed, kooks headers, FAST 92 intake.
Help... anyone? What should I check next? If it is valvetrain or bottom end damage wouldn't it still be loud with the cylinder not firing?
What I have done so far...
change plug on #1 cylinder
ensure plug is fully and properly threaded
swap plug wires
swap coil packs
swap injectors
None of the above made a difference. Still ON / OFF if cylinder was firing or not.
Then I checked the header bolts to ensure they were tight, no issues there, headers on tight.
Then I held my breath and pulled the valve cover - fortunately didn't see any metal or evidence of damage and there was no play in the rockers, push rods, etc.
Engine is an L92 bored/stroked to 427, TFS 235 heads, cammed, kooks headers, FAST 92 intake.
Help... anyone? What should I check next? If it is valvetrain or bottom end damage wouldn't it still be loud with the cylinder not firing?
10-09-2010, 07:43 PM
#2
On The Tree
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Make sure the exhaust valve is being opened by the cam, but sounds like a bad / burnt valve........................
Bird
Bird
Last edited by Bird; 10-09-2010 at 07:50 PM.
10-10-2010, 10:13 AM
#5
Did that, forgot to mention... compression on #1 was around 170, #2 was around 160. Didn't check all cylinders as the problem has been isolated to #1.
So assuming compression is good what does that rule out? Burned valve, rings (although I didn't suspect that)...?
So assuming compression is good what does that rule out? Burned valve, rings (although I didn't suspect that)...?
