Ticking comes and goes
03-03-2018, 06:18 PM
#92
Nordschleife Master
Here’s mine: https://youtu.be/EWlR2s1xbqo
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.
03-03-2018, 08:11 PM
#93
Rennlist Member
Here’s mine: https://youtu.be/EWlR2s1xbqo
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.
03-04-2018, 11:42 AM
#95
might not imply a problem
996 ticking noises can be signs of a problem or just a feature of the engine and its management system.
If it is a tiptronic and at tickover the noise goes away or reduces if you engage “D” or if you switch on the air-con and it goes away or reduces and your tail pipes are equally sooty - you probably do not have a serious problem (boroscope to check).
The model has several reasons for a tick and several cures and sometimes it cannot be cured.It is usually from the bank 2 area half way from the crank to the camshaft, back of engine cylinder 4 area.All engines speed up and slow down between each firing stroke and this causes a shake to the various chains and cams and tensioners.
When tickover was adjusted by a screw you raised it until any “ticking stopped” (hence the term tickover) but to reduce emissions the tickover speed drops as the engine warms up so older engines that a very free running and with lower oil pressure and weaker leaking tappets can lower the revs too far when hot (especially if you leave it running to listen for a tick).Revs can be increased when re-mapping – there are 8 or 10 settings at different temperatures – sometimes raising these sorts the problem.
Some temsioners plastic followers have a steel domed piece for the steel tensioner to press against – after a while the dome flattens and replacing this with a nylon 66 one can reduce noises.The tensioners are a very poor design.
No reservoirs and not even a sprung loaded ball non-return valve. Furthermore the feed is after all the other drains on oil pressure and flow from the tappets, variocam systems, camshaft bearing areas etc. The tensioner has a tiny flat plate that is supposed to seal the return stroke if the chains ******.
The bank 1 tensioner allows the plate to fall onto the sealing face so when you strip it you usually find it full of oil still. The bank 2 one is upside down and is always empty when you strip it. There is not even a seal on the piston.
We tried making ones with different springs and a ball valve which sometimes worked often didn’t and finally concluded that at tickover the tensioner piston just flaps back and forth and the oil flow form the head isn’t sufficient to keep it pressured – hence the tick.Any uneven running between cylinders makes things worse and rebuilds with better than standard compression or bigger pistons can create a slight problem.
Other reasons already previously listed by other contributors are all valid.Because the flywheel speed sensor reads the speed evert 3 power strokes any imbalance can only be adjusted by the ECU on the third stroke and as cylinder 4 is next and the bank 2 cam chain on the end of the IMS shaft feels any adjustment next, that chain receives the jerk.So unless you have other problems or signs – it is probably just a noise that many have wasted hours trying to fix and usually eventually give up after absolutely everything has been changed and the tick is still there.
Baz
If it is a tiptronic and at tickover the noise goes away or reduces if you engage “D” or if you switch on the air-con and it goes away or reduces and your tail pipes are equally sooty - you probably do not have a serious problem (boroscope to check).
The model has several reasons for a tick and several cures and sometimes it cannot be cured.It is usually from the bank 2 area half way from the crank to the camshaft, back of engine cylinder 4 area.All engines speed up and slow down between each firing stroke and this causes a shake to the various chains and cams and tensioners.
When tickover was adjusted by a screw you raised it until any “ticking stopped” (hence the term tickover) but to reduce emissions the tickover speed drops as the engine warms up so older engines that a very free running and with lower oil pressure and weaker leaking tappets can lower the revs too far when hot (especially if you leave it running to listen for a tick).Revs can be increased when re-mapping – there are 8 or 10 settings at different temperatures – sometimes raising these sorts the problem.
Some temsioners plastic followers have a steel domed piece for the steel tensioner to press against – after a while the dome flattens and replacing this with a nylon 66 one can reduce noises.The tensioners are a very poor design.
No reservoirs and not even a sprung loaded ball non-return valve. Furthermore the feed is after all the other drains on oil pressure and flow from the tappets, variocam systems, camshaft bearing areas etc. The tensioner has a tiny flat plate that is supposed to seal the return stroke if the chains ******.
The bank 1 tensioner allows the plate to fall onto the sealing face so when you strip it you usually find it full of oil still. The bank 2 one is upside down and is always empty when you strip it. There is not even a seal on the piston.
We tried making ones with different springs and a ball valve which sometimes worked often didn’t and finally concluded that at tickover the tensioner piston just flaps back and forth and the oil flow form the head isn’t sufficient to keep it pressured – hence the tick.Any uneven running between cylinders makes things worse and rebuilds with better than standard compression or bigger pistons can create a slight problem.
Other reasons already previously listed by other contributors are all valid.Because the flywheel speed sensor reads the speed evert 3 power strokes any imbalance can only be adjusted by the ECU on the third stroke and as cylinder 4 is next and the bank 2 cam chain on the end of the IMS shaft feels any adjustment next, that chain receives the jerk.So unless you have other problems or signs – it is probably just a noise that many have wasted hours trying to fix and usually eventually give up after absolutely everything has been changed and the tick is still there.
Baz
Last edited by bazhart; 03-05-2018 at 11:14 AM. Reason: spelling
03-05-2018, 10:05 PM
#97
Rennlist Member
Very interesting comments. Thanks for posting!
03-15-2018, 09:46 AM
#100
Nordschleife Master
Yes engine is almost ready to put back in the car. I got it done by a place in Quebec Canada which saves a lot of red tape, currency conversion and customs hassle of shipping and having work done in the USA.
03-15-2018, 12:02 PM
#102
Nordschleife Master
04-27-2018, 05:27 PM
#103
Instructor
Thread Starter
Update 4/27
Went for a 100 mile drive today. Everything fully warm and flowing, as they say. Got home and in the garage she ticks softly and also seems to fade in and out. Resigned to her staying annoying or Armageddon looming. Until then I'll update as needed.
05-02-2018, 12:44 PM
#104
Nordschleife Master
That is exactly how mine was when it first starting ticking. Looks like you got some time before its get worse and starts freaking out the mechanics like mine did.
05-05-2018, 12:42 AM
#105
Instructor
Thread Starter
Yeah, apparently since I do about 5k in mileage per year I have about 2 to 3 years til oh crap time. Was thinking of selling the car b4 all this but now gotta ride it til something absolute occurs. Going to enjoy the summer instead. Thx for the numerous posts