Ticking comes and goes
02-26-2018, 04:24 AM
#76
Burning Brakes
I recall reading that the crank bearing case has oil jets aimed at the piston skirts, but they aren’t activated until the oil pressure reaches 1.8 bar. I don’t know at what rpm that occurs, but could it be possible you hear the knock at the low pressure/rpm, and it goes away when the 1.8 threshold is reached?
just an idea...
just an idea...
02-27-2018, 10:17 PM
#78
Track Day
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Location: RI
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Long shot, but if you are suspecting oil pressure problem, check the swirl pots. There was a post here about these clogging up with chain pad debris.
https://rennlist.com/forums/996-foru...-solution.html
https://rennlist.com/forums/996-foru...-solution.html
02-28-2018, 01:37 AM
#79
Rennlist Member
I know Ahsai mentioned this early on, and on one video the sound was loudest right as your phone passed under the passenger side Cat. Check this again and listen (or have your Technician) directly to the passenger side Cat.
There has been more than a few miss this as the source that "sounds" like piston slap.
There has been more than a few miss this as the source that "sounds" like piston slap.
03-01-2018, 07:30 PM
#81
Nordschleife Master
Well here is the quiet engine again, after a lengthy morning of driving. It ticked at various times during the day. Getting ticked off
https://www.youtube.com/watch?v=Z6dp...ature=youtu.be
https://www.youtube.com/watch?v=Z6dp...ature=youtu.be
Found a old video of my tick at cold start
03-01-2018, 11:42 PM
#82
Rennlist Member
Mine after being warmed up won't have a tick. Only did it while cold. Then eventually it started ticking all the time but sometime rarely would stop and sound great until the next stop light.
Found a old video of my tick at cold start
https://www.youtube.com/watch?v=KMhcebPSLz4
Found a old video of my tick at cold start
https://www.youtube.com/watch?v=KMhcebPSLz4
03-02-2018, 09:39 AM
#83
Nordschleife Master
03-02-2018, 02:55 PM
#85
Nordschleife Master
4,5,6 cylinders were scored on mine. I drove it for a at 30k km ticking with it like that. The sound is piston slap
When I had it borescoped they could only tell that one of the cylinders were scored, after pulling it apart and clean up 3 were scored.
Last edited by jumper5836; 03-14-2018 at 07:10 PM.
03-02-2018, 03:38 PM
#86
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How was it running after 30km driven with the ticking? I'm curious as to how long one would be able to run with ticking before it becomes necessary to decide what course of action to take assuming the ticking is piston slap not some other source.
03-02-2018, 03:54 PM
#87
Nordschleife Master
30,0000 km. It was tracked during this time as well. Lot of blue smoke at startup when engine was below 50F and after track sessions. As I said it was a gradual noise and eventually endup up like that is in the vid all the time. The car was even put on a awd dyno and was showing up the similar hp/torque as other 996 4S's. I imagine it could still run like that until the cylinder eventually cracked but wasn't going to take the chance. I think the piston slap was worse at idle and went away under load so driving it hard didn't matter it was when it was idling that would have killed it.
03-02-2018, 04:21 PM
#88
Instructor
Thread Starter
30k is a bit of mileage to play with for me. Lots of pieces her to contemplate. As I come across more I will continue to post. Seems that several are dealing with this. Far from done for now.
03-03-2018, 11:25 AM
#90
Rennlist Member
Here’s mine:
Only happens on cold start from about 5 seconds in for about 3 minutes if I let it idle. If I drive off immediately, it goes away after maybe 5 seconds. Doesn’t happen when warming up or hot.
Never any debris in the oil filter.
Sounds like piston slap to me on many cylinders, but then sometimes downgrades to what sounds like a single knock from a single cylinder.
Only happens on cold start from about 5 seconds in for about 3 minutes if I let it idle. If I drive off immediately, it goes away after maybe 5 seconds. Doesn’t happen when warming up or hot.
Never any debris in the oil filter.
Sounds like piston slap to me on many cylinders, but then sometimes downgrades to what sounds like a single knock from a single cylinder.