Engine tapping noises some causes discussed
Discussion
Sunnysidebb said:
Is there any chance this thread could be stored in a better place once it dies a death. It has to be one of those posts you will want to look back on and find easy.
Any chance it could be made a sticky ( Mods ????) For all us paranoid owners this post offers some good information.
How a bout it?????
Frank
Frank - just click on 'bookmarks' above.Any chance it could be made a sticky ( Mods ????) For all us paranoid owners this post offers some good information.
How a bout it?????
Frank
monthefish said:
Sunnysidebb said:
Is there any chance this thread could be stored in a better place once it dies a death. It has to be one of those posts you will want to look back on and find easy.
Any chance it could be made a sticky ( Mods ????) For all us paranoid owners this post offers some good information.
How a bout it?????
Frank
Frank - just click on 'bookmarks' above.Any chance it could be made a sticky ( Mods ????) For all us paranoid owners this post offers some good information.
How a bout it?????
Frank
It would be nice for other members to find easier as well????
Do we have a technical section dedicated to Porsche's on PH. Things like DIY stuff and info???? Would be nice to have a section like that
Frank
Sunnysidebb said:
Cheers's just done it.
It would be nice for other members to find easier as well????
Do we have a technical section dedicated to Porsche's on PH. Things like DIY stuff and info???? Would be nice to have a section like that
Frank
I've made it a wiki - see under "This Forum" menu, then Shows Wikis.It would be nice for other members to find easier as well????
Do we have a technical section dedicated to Porsche's on PH. Things like DIY stuff and info???? Would be nice to have a section like that
Frank
monthefish said:
Just out of curiosity, what causes a piston/bore to become scored?
There are at least a couple of causes.Dirt gets in the cylinder/between the piston during assembly or the parts were not cleaned properly and upon start up (or just turning the engine over) this dirt (not dirt dirt but metal swarf, metal shavings, abrasive grit, etc.) gouges a groove until the object breaks up. In some cases the object can break a ring.
When I rebuilt engines I was taught cleanliness was next to godliness and really worked hard to ensure the engines and all their parts were clean clean clean. Engine factories are probably clean but stuff happens.
Or if during assembly a ring breaks. Failure arising from an assembly error. Or the ring breaks after assembly. Mechanical failure. Rings are just like other engine parts. They can fail at any time and if one does in doing so can score the cylinder.
Another possible cause is the engine is new and being new it sheds debris. All cast/machined surfaces do this.
A new engine has lot of friction. During break in this friction diminishes. And a new engine with some miles on its oil will have contaminated the oil with unburned gas and water -- normal combustion by-products. This reduces the oil's ability to fight metal to metal contact.
Then the engine is run hard. Hard enough the heat generated from the harder running and the increased heat from the higher piston speeds breaks down the oil and metal to metal contact takes place. Either at the ring to cylinder interface or at the piston to cylinder wall interface.
Metal to metal contact can generate so much heat that the two pieces temporarily weld themselves together. But of course the weld breaks/fractures as soon as it forms. But in doing so the fracture almost never happens evenly. This results in say if the majority of the weld metal stays with the piston as the piston travels down and then up the bore this metal will score/gouge a groove. In some cases the metal welds again to the cylinder and further damage can occur.
There are other causes: Lean running, detonation, or overly rich running that washes oil from the cylinder walls, and so on. But they all boil down to metal making severe contact with metal under high heat and high pressure conditions.
Sincerely,
Rockster.
helmutlaang said:
I have the exact same car as you and mine also has that tapping noise,particually when hot
Interestingly,I think my DMF is very slightly worn as there is a slight clunk when switching off.My 53 plate mondeo does exactly the same and has done for thousands of miles without getting worse.
Just to follow up on this,I am having the clutch/flywheel changed next week.Release bearing also noisy.Interestingly,I think my DMF is very slightly worn as there is a slight clunk when switching off.My 53 plate mondeo does exactly the same and has done for thousands of miles without getting worse.
Regarding the ticking noise:It is still there and I have noticed that under load it sounds like the exhaust is blowing as it gets a lot louder but when revved in Netural the ticking goes and sounds fine.After reading Baz's original post again It may be the manifold issue as the bolts are fairly badly corroded.I will nivestigate further when the cars on the ramp.
helmutlaang said:
Just to follow up on this,I am having the clutch/flywheel changed next week.Release bearing also noisy.
Regarding the ticking noise:It is still there and I have noticed that under load it sounds like the exhaust is blowing as it gets a lot louder but when revved in Netural the ticking goes and sounds fine.After reading Baz's original post again It may be the manifold issue as the bolts are fairly badly corroded.I will nivestigate further when the cars on the ramp.
I suspect that mine might be an exhaust issue too. My car is really 'barky' when cold (actually, it sounds great, like a racing engine), but everything gets much quieter when things warm up.Regarding the ticking noise:It is still there and I have noticed that under load it sounds like the exhaust is blowing as it gets a lot louder but when revved in Netural the ticking goes and sounds fine.After reading Baz's original post again It may be the manifold issue as the bolts are fairly badly corroded.I will nivestigate further when the cars on the ramp.
I assume that various parts of the exhaust are expanding and 'plugging holes'. The ticking only comes when the engine is warm, so maybe it's an acoustic byproduct of the exhaust being warmer.
Still, I'm not going to worry about it!
One of our customer cars (996tt with 90k mileage) was in for a 700 kit upgrade and during the pre inspection it was noticeable that noise was coming from the crank. Using a stethoscope the noise was pinpointed to the oil pump. The upgrade was refused. However after further discussion and a quick drive in an 800 kit, the customer decided to go for the 800 kit with engine build. And a good job too!
After stripping down the engine the oil pump itself was on its last legs, but what was surprising was the state of 4 of the tappets. The shaft in the middle of the tappets (that actually lifts) just fell out on it's own. Now whilst these can be considered to be a "wear and tear" item, in comparison to other engines we have stripped, none of the others had this level of lifter failure.
It was also noticeable the state of the oil in the crank - looked like the oil had not been frequently changed.
Anyway for the customer it is a result - suspect that his engine was not for much longer.
What I would say is that other engines we have stripped that had the same mileage, where the oil pump was not making any noise, did not show this level of wear and tear - some, but not to this level.
After stripping down the engine the oil pump itself was on its last legs, but what was surprising was the state of 4 of the tappets. The shaft in the middle of the tappets (that actually lifts) just fell out on it's own. Now whilst these can be considered to be a "wear and tear" item, in comparison to other engines we have stripped, none of the others had this level of lifter failure.
It was also noticeable the state of the oil in the crank - looked like the oil had not been frequently changed.
Anyway for the customer it is a result - suspect that his engine was not for much longer.
What I would say is that other engines we have stripped that had the same mileage, where the oil pump was not making any noise, did not show this level of wear and tear - some, but not to this level.
Scavenge pump noise is common on a 996 turbo. The cam followers "falling apart" when removed isn't uncommon either. To be fair they are held together by the cam, so they can't go anywhere. We chased a misfire down on our 996 turbo and in the course of doing that changed all the cam followers to eliminate them from our enquiries.
The thing to watch out for on 996 turbos is recent rev range 2 activity (within the last 100 hours or so. We saw a car recently which had been there within the past 25 hours or so and unfortunately had a slight noise from the timing dept which didn't go away as you increased revs. So not one for us but you could have easily missed it.
We've corrected a couple of 996 turbos now to save them from a bigger bill when everything ends up on the tarmac !
Henry
The thing to watch out for on 996 turbos is recent rev range 2 activity (within the last 100 hours or so. We saw a car recently which had been there within the past 25 hours or so and unfortunately had a slight noise from the timing dept which didn't go away as you increased revs. So not one for us but you could have easily missed it.
We've corrected a couple of 996 turbos now to save them from a bigger bill when everything ends up on the tarmac !
Henry
Rockster said:
There are at least a couple of causes.
Dirt gets in the cylinder/between the piston during assembly or the parts were not cleaned properly and upon start up (or just turning the engine over) this dirt (not dirt dirt but metal swarf, metal shavings, abrasive grit, etc.) gouges a groove until the object breaks up. In some cases the object can break a ring.
When I rebuilt engines I was taught cleanliness was next to godliness and really worked hard to ensure the engines and all their parts were clean clean clean. Engine factories are probably clean but stuff happens.
Or if during assembly a ring breaks. Failure arising from an assembly error. Or the ring breaks after assembly. Mechanical failure. Rings are just like other engine parts. They can fail at any time and if one does in doing so can score the cylinder.
Another possible cause is the engine is new and being new it sheds debris. All cast/machined surfaces do this.
A new engine has lot of friction. During break in this friction diminishes. And a new engine with some miles on its oil will have contaminated the oil with unburned gas and water -- normal combustion by-products. This reduces the oil's ability to fight metal to metal contact.
Then the engine is run hard. Hard enough the heat generated from the harder running and the increased heat from the higher piston speeds breaks down the oil and metal to metal contact takes place. Either at the ring to cylinder interface or at the piston to cylinder wall interface.
Metal to metal contact can generate so much heat that the two pieces temporarily weld themselves together. But of course the weld breaks/fractures as soon as it forms. But in doing so the fracture almost never happens evenly. This results in say if the majority of the weld metal stays with the piston as the piston travels down and then up the bore this metal will score/gouge a groove. In some cases the metal welds again to the cylinder and further damage can occur.
There are other causes: Lean running, detonation, or overly rich running that washes oil from the cylinder walls, and so on. But they all boil down to metal making severe contact with metal under high heat and high pressure conditions.
Sincerely,
Rockster.
manufacturing metal matrix casting errors may have occurred in the 2004-2008 these issues may lead to the scored boring Dirt gets in the cylinder/between the piston during assembly or the parts were not cleaned properly and upon start up (or just turning the engine over) this dirt (not dirt dirt but metal swarf, metal shavings, abrasive grit, etc.) gouges a groove until the object breaks up. In some cases the object can break a ring.
When I rebuilt engines I was taught cleanliness was next to godliness and really worked hard to ensure the engines and all their parts were clean clean clean. Engine factories are probably clean but stuff happens.
Or if during assembly a ring breaks. Failure arising from an assembly error. Or the ring breaks after assembly. Mechanical failure. Rings are just like other engine parts. They can fail at any time and if one does in doing so can score the cylinder.
Another possible cause is the engine is new and being new it sheds debris. All cast/machined surfaces do this.
A new engine has lot of friction. During break in this friction diminishes. And a new engine with some miles on its oil will have contaminated the oil with unburned gas and water -- normal combustion by-products. This reduces the oil's ability to fight metal to metal contact.
Then the engine is run hard. Hard enough the heat generated from the harder running and the increased heat from the higher piston speeds breaks down the oil and metal to metal contact takes place. Either at the ring to cylinder interface or at the piston to cylinder wall interface.
Metal to metal contact can generate so much heat that the two pieces temporarily weld themselves together. But of course the weld breaks/fractures as soon as it forms. But in doing so the fracture almost never happens evenly. This results in say if the majority of the weld metal stays with the piston as the piston travels down and then up the bore this metal will score/gouge a groove. In some cases the metal welds again to the cylinder and further damage can occur.
There are other causes: Lean running, detonation, or overly rich running that washes oil from the cylinder walls, and so on. But they all boil down to metal making severe contact with metal under high heat and high pressure conditions.
Sincerely,
Rockster.
baz knows all about that and could probably explain the process better
its still an interesting subject as nobody has ever really got to the bottom of who is to blame regarding all of the low mileage engine failures
one thing is for sure and that is its not just down to the owners and there usage as the failures are very similar,some well known engineers say 0-40 oil doesnt help the issue either but the subject needs as much input as these engines may reach a point where the first question from a prospective buyer will be.... has it had the liners done and has it had the IMS bearing done ?
It splits up into two main points
who is to blame?
How do we fix it?
hiding behind 3k of servicing and warranty as the cars get older wont do
You could think of it like this.
All engines have very small internal variations resulting from manufacturing tolerance ranges and selection and some have internal stress relieving of critical parts as the engine gets used that varies as well.
Despite this - imagine a perfectly reliable engine type that can stand all those variations and still perform acceptably. Introduce some new technology 9Like Lokasil bores) change the IMS bearing system - but only build a small capacity engine that still proves reasonably reliable (Boxster 2.5).
Now - as each year of production goes by, slightly increase the piston face load (by increasing torque, power output or capacity) and at the same time slightly reduce the coolant balance inside the engine so some parts run hotter than they did before. Then sell them to the same owners (with a variety of different ways of driving them and looking after them - change owners - introduce another way of driving and looking after them - change the servicing business as well) and gradually some of those previously reliable engines will start to fail.
Then ignore the feedback and continue with the very same regime (2.7, 3.2, 3.4, 3.6, 3.8 etc) - but do nothing to compensate for the increased loads and outputs and do nothing to improve the cooling and gradually the numbers failing will increase and come to public scrutiny and the questions above will start to be asked.
So why were steps not taken to gradually adjust these known weak areas during this gradual process? The only people who can answer the question are the manufacturers - it is their product and they stand to benefit or suffer as a result of their decisions. Are they suffering? who was right? what do you think?
Baz
All engines have very small internal variations resulting from manufacturing tolerance ranges and selection and some have internal stress relieving of critical parts as the engine gets used that varies as well.
Despite this - imagine a perfectly reliable engine type that can stand all those variations and still perform acceptably. Introduce some new technology 9Like Lokasil bores) change the IMS bearing system - but only build a small capacity engine that still proves reasonably reliable (Boxster 2.5).
Now - as each year of production goes by, slightly increase the piston face load (by increasing torque, power output or capacity) and at the same time slightly reduce the coolant balance inside the engine so some parts run hotter than they did before. Then sell them to the same owners (with a variety of different ways of driving them and looking after them - change owners - introduce another way of driving and looking after them - change the servicing business as well) and gradually some of those previously reliable engines will start to fail.
Then ignore the feedback and continue with the very same regime (2.7, 3.2, 3.4, 3.6, 3.8 etc) - but do nothing to compensate for the increased loads and outputs and do nothing to improve the cooling and gradually the numbers failing will increase and come to public scrutiny and the questions above will start to be asked.
So why were steps not taken to gradually adjust these known weak areas during this gradual process? The only people who can answer the question are the manufacturers - it is their product and they stand to benefit or suffer as a result of their decisions. Are they suffering? who was right? what do you think?
Baz
carcar said:
manufacturing metal matrix casting errors may have occurred in the 2004-2008 these issues may lead to the scored boring
baz knows all about that and could probably explain the process better
its still an interesting subject as nobody has ever really got to the bottom of who is to blame regarding all of the low mileage engine failures
one thing is for sure and that is its not just down to the owners and there usage as the failures are very similar,some well known engineers say 0-40 oil doesnt help the issue either but the subject needs as much input as these engines may reach a point where the first question from a prospective buyer will be.... has it had the liners done and has it had the IMS bearing done ?
It splits up into two main points
who is to blame?
How do we fix it?
hiding behind 3k of servicing and warranty as the cars get older wont do
Who is to blame? Porsche. Porsche's name is on the car. Ultimately, Porsche bears full responsisibility for any failures that occur.baz knows all about that and could probably explain the process better
its still an interesting subject as nobody has ever really got to the bottom of who is to blame regarding all of the low mileage engine failures
one thing is for sure and that is its not just down to the owners and there usage as the failures are very similar,some well known engineers say 0-40 oil doesnt help the issue either but the subject needs as much input as these engines may reach a point where the first question from a prospective buyer will be.... has it had the liners done and has it had the IMS bearing done ?
It splits up into two main points
who is to blame?
How do we fix it?
hiding behind 3k of servicing and warranty as the cars get older wont do
But failures will occur. That is why new cars come with a new car warranty. The Porsche warranty is better than most, at least in the USA, with a 4 year, 50K mile warranty.
The problem is that many cars do not get used much and it takes usage to bring out any inherent problems. I would think though in cases where the car didn't get used much, and the warranty expired on time, that as long as the car had the proper servicing, was not abused or misused or modified, that Porsche would goodwill engine failures. If it wanted to do it 'secretly' I would have no problem with that either.
Sincerely,
Rockster.
Ok so I have a ticking/tapping sound from the top end of my 997. It is intermittent and goes after about 5 minutes, after the ticking stops I get ims and error reads camshaft position sensor alignment.
It sounds like noisy lifters but the tapping occurs after I hit the 4k rpm could it be a variocam issue?
Any and all help appreciated
It sounds like noisy lifters but the tapping occurs after I hit the 4k rpm could it be a variocam issue?
Any and all help appreciated
Great info here. I am looking at a Boxster 986 2.5 with only 49000 miles. Full service history from Porsche. When cold the engine starts first turn and there are no noises (tapping). After a short run and warmed up (5miles) it start to tap, light tapping in time with the engine revs from Rickover to higher revs, doesn't get loader but frequency increases with revs. I would say in time with revs compared to a bearing which has no direct link to engine rotation.
The noise sounds like a hydronic tappet but I would expect this to be there at start up from cold when oil pressure is lowest and quiet down after warm up/ oil pressure increase. This seems the opposite no noise at cold but a distinct tapping when warm.
I have no idea if the ims bearing has ever been changed as the service book stamps are there but there is no documentation to see what other repairs were carried out.
Any idea please?
The noise sounds like a hydronic tappet but I would expect this to be there at start up from cold when oil pressure is lowest and quiet down after warm up/ oil pressure increase. This seems the opposite no noise at cold but a distinct tapping when warm.
I have no idea if the ims bearing has ever been changed as the service book stamps are there but there is no documentation to see what other repairs were carried out.
Any idea please?
Hi Baz, thanks for the writeup.
I have a 56000 mile 997 c2s engine coming to you, and symptoms were, tappett noise bank 2, noise would increase in volume with revs, upto 2000rpm and then 90% of the noise would go, it did sound like a sticking tappett.
As the noise was on the loud side, I carried out a borescope on bank 2, and was shocked to see the extent of the damage,
especially cylinder 6,and noise was obvious the piston rocking in the bore,will try and attach image.
Chris in Cardiff
I have a 56000 mile 997 c2s engine coming to you, and symptoms were, tappett noise bank 2, noise would increase in volume with revs, upto 2000rpm and then 90% of the noise would go, it did sound like a sticking tappett.
As the noise was on the loud side, I carried out a borescope on bank 2, and was shocked to see the extent of the damage,
especially cylinder 6,and noise was obvious the piston rocking in the bore,will try and attach image.
Chris in Cardiff
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