Name that noise!! Engine tick
10-22-2015, 02:12 PM
#16
Drifting
Dissect filter,inspect bottom of sump plate.Hope you don't find 'gold'. Worst case, you eliminate bearing issues,find early warning of chainramp deterioration. Cheap and easy PM.The armchair diagnostics is of little help in my experience.
10-22-2015, 02:34 PM
#17
10-22-2015, 05:09 PM
#19
I do, but in all the years I was into auto mechanics and rebuilding engines, noises repeating at half crank speed was a clear hint it was valve train noise, and if the noise happened at crank speed it was a hint at bottom-end, including piston slap. Are these flat sixes different? Because all the indie Porsche mechanics I've spoken with said lifters tick at half rate and pistons slap at full. If they don't know what they're talking about then it's pretty scary.
10-22-2015, 05:56 PM
#20
If you check out the video in post #9, that's a confirmed cylinder scoring (you can PM "Van" to confirm). Now count how many ticks/sec. I counted 6~7 ticks/sec, which is about half the idle crank speed (~700 rpm). You will hear again and again this rhythm on all the other similar confirmed cases.
If what the mechanics said were right, all these video you should be 11~12 ticks per second. You be the judge
I can post more videos if ppl are interested.
If what the mechanics said were right, all these video you should be 11~12 ticks per second. You be the judge
I can post more videos if ppl are interested.
10-22-2015, 06:14 PM
#22
Three Wheelin'
Hmm, my car would make similar sound on the passenger side only when cold though. It was fainter, but you could definitely hear it. After it would warm up it was never present. Interesting.
10-22-2015, 06:26 PM
#23
Not sure if it's universal in all cases but this video shows the worn piston skirt makes the piston top hit the head hence the knocking sound
You can see how shinny that area is (part of the piston top). Also note the length of the scored area in the cylinder. Definitely something you will be able to see with a boroscope from the spark plug holes.
You can see how shinny that area is (part of the piston top). Also note the length of the scored area in the cylinder. Definitely something you will be able to see with a boroscope from the spark plug holes.
10-22-2015, 06:26 PM
#24
Rennlist Member
If you check out the video in post #9, that's a confirmed cylinder scoring (you can PM "Van" to confirm). Now count how many ticks/sec. I counted 6~7 ticks/sec, which is about half the idle crank speed (~700 rpm). You will hear again and again this rhythm on all the other similar confirmed cases.
If what the mechanics said were right, all these video you should be 11~12 ticks per second. You be the judge
I can post more videos if ppl are interested.
If what the mechanics said were right, all these video you should be 11~12 ticks per second. You be the judge
I can post more videos if ppl are interested.
10-22-2015, 06:31 PM
#25
10-22-2015, 06:39 PM
#26
Well if cylinder scoring and lifter noise both sound alike and both occur at half the crank speed then the tapping noise is not specific to either one, and therefore unless there are other concurrent symptoms (such as smoking, one oil-sooted tailpipe, or excessive oil consumption), the tick could just as well be a lifter, and bore-scoring is an incidental finding because the owner or a mechanic scopes it.
Not a bad idea though, because even if a $6k lifter job would stop the tapping, nobody would want to spend that on an engine with cylinders in the process of failing.
Personally as I said before, if hypothetically the only symptom my engine with 60K+ was exhibiting was a mild tapping for a minute or two during warmup, I wouldn't be in any hurry to throw thousands of dollars at it.
Not a bad idea though, because even if a $6k lifter job would stop the tapping, nobody would want to spend that on an engine with cylinders in the process of failing.
Personally as I said before, if hypothetically the only symptom my engine with 60K+ was exhibiting was a mild tapping for a minute or two during warmup, I wouldn't be in any hurry to throw thousands of dollars at it.
10-22-2015, 06:42 PM
#27
How long and many miles was the noise present, and did you ever look for and find the exact cause? (Diagnostics of all kinds fascinate me)
Last edited by Ben Z; 10-22-2015 at 08:20 PM.
10-22-2015, 06:48 PM
#29
Well if cylinder scoring and lifter noise both sound alike and both occur at half the crank speed then the tapping noise is not specific to either one, and therefore unless there are other concurrent symptoms (such as smoking, one oil-sooted tailpipe, or excessive oil consumption), the tick could just as well be a lifter, and bore-scoring is an incidental finding because the owner or a mechanic scopes it.
Not a bad idea though, because even if a $6k lifter job would stop the tapping, nobody would want to spend that on an engine with cylinders in the process of failing.
Personally as I said before, if hypothetically the only symptom my engine with 60K+ was exhibiting was a mild tapping for a minute or two during warmup, I wouldn't be in any hurry to throw thousands of dollars at it.
Not a bad idea though, because even if a $6k lifter job would stop the tapping, nobody would want to spend that on an engine with cylinders in the process of failing.
Personally as I said before, if hypothetically the only symptom my engine with 60K+ was exhibiting was a mild tapping for a minute or two during warmup, I wouldn't be in any hurry to throw thousands of dollars at it.
