Pronounced engine 'tick' at startup, then fades at op temps.

[Hobbes]

I have a 2000 996 C2 Cab with 132k miles. My engine has acquired a ticking/knocking sound on a cold startup and fades to a 'quieter', negligible tick/knock at operating temperatures.

Two videos of the sound:

and

Background

I hooked up the Durametric software due to a high idle and as I began looking at the actual values for different things, I came across a camshaft deviation bank 1 reading of -12.02 and camshaft deviation bank 2 reading of -5.21. One is out of limit and the other is close. I'm guessing the timing is off due to worn parts and just the age of the engine. As a result, I plan on dropping the engine/trans this weekend and replacing the chains, tensioners, pad brake set for the chains and some other things.

Additional Information:

The engine runs strong.

I've cleaned the MAF (replaced two years ago).

When I engage the clutch, the noise is still there.

The ticking increases with rpms.

Ticking is very faint at normal operating temperatures.

Now with this ticking sound, I'm searching for potential causes. I would like to order parts soon, but don't want to waste money either on parts that are unrelated. Can anyone provide some insight and what you did to resolve the issue? Also is there a measureable value in the durametric software to help focus on the problem?

Thanks

[JFP in PA]

I have a 2000 996 C2 Cab with 132k miles. My engine has acquired a ticking/knocking sound on a cold startup and fades to a 'quieter', negligible tick/knock at operating temperatures.

Two videos of the sound:

and

Background

I hooked up the Durametric software due to a high idle and as I began looking at the actual values for different things, I came across a camshaft deviation bank 1 reading of -12.02 and camshaft deviation bank 2 reading of -5.21. One is out of limit and the other is close. I'm guessing the timing is off due to worn parts and just the age of the engine. As a result, I plan on dropping the engine/trans this weekend and replacing the chains, tensioners, pad brake set for the chains and some other things.

Additional Information:

The engine runs strong.

I've cleaned the MAF (replaced two years ago).

When I engage the clutch, the noise is still there.

The ticking increases with rpms.

Ticking is very faint at normal operating temperatures.

Now with this ticking sound, I'm searching for potential causes. I would like to order parts soon, but don't want to waste money either on parts that are unrelated. Can anyone provide some insight and what you did to resolve the issue? Also is there a measureable value in the durametric software to help focus on the problem?

Thanks

Judging by the extreme cam deviation values, and the year of the car, you have a five chain motor that is suffering from wear on the cam tensioning pads located between the two cams on either one or both heads. In your case, bank one seems to be the worst offender. This is a common problem on the five chain cars and can be fixed by replacing the worn parts:

There was just a similar thread about this problem: http://www.renntech.org/forums/topic/46101-camshaft-position-1-deviation-of-897/?hl=%2Bworn+%2Btensioner+%2Bpads#entry252738

[Hobbes]

Thanks JFP. I am following the other post you mentioned. I didn't know if the ticking and the camshaft deviation were related issues. It does make sense the tensioner pads get old and worn causing the chains to 'flap/knock' around a little. It sounds like I ordered the right parts for the job. I am going to drop the oil pan cover to make sure there aren't any foreign objects in there. Xmac recommended this and won't be much additional effort to check it with the engine out.

[JFP in PA]

Thanks JFP. I am following the other post you mentioned. I didn't know if the ticking and the camshaft deviation were related issues. It does make sense the tensioner pads get old and worn causing the chains to 'flap/knock' around a little. It sounds like I ordered the right parts for the job. I am going to drop the oil pan cover to make sure there aren't any foreign objects in there. Xmac recommended this and won't be much additional effort to check it with the engine out.

The cam deviation is due to slackness on one or more timing chains, which is also where the noise comes from. Sometimes it is just the hydraulic tensioners causing the issue, but more often on the five chains it is the small shoes between the cams.

[RD996]

I have a very similar sound coming from the passenger side of my motor - 99 C2 with 90K miles. Very loud upon cold start up after a week, not so loud starting up cold after a day. After about 15 seconds it mutes quite a bit and once the motor is warm I can barely hear it at idle. It goes away when I rev the motor as well. An Indy told me he thought it was a lifter but I got the impression he didn't put too much thought into it.

JFP: Is replacing all this cam chain stuff pretty labor/parts cost intensive to the point of tearing down the whole motor? I'm thinking about having a more thorugh inspection done to pin point the cause and determine the overall health of the motor with regards to cylinder wear etc. Do worn out timing chains and guides/tensioners etc cause catastrophic failures?

I did pull the original sump recently to replace with a deep sump and there was no plastic debris I could see.

Thanks

Rich

Edited April 21, 2014 by RD996

[Hobbes]

Rich,

There is a pretty good step-by-step on Pelican Parts website I intend to use.

http://www.pelicanparts.com/techarticles/996_tech.htm The last two articles under the 'Engine' section. I can't speak to the labor portion as I have not yet done it yet, but the parts are pretty reasonable.

Ken

[JFP in PA]

I have a very similar sound coming from the passenger side of my motor - 99 C2 with 90K miles. Very loud upon cold start up after a week, not so loud starting up cold after a day. After about 15 seconds it mutes quite a bit and once the motor is warm I can barely hear it at idle. It goes away when I rev the motor as well. An Indy told me he thought it was a lifter but I got the impression he didn't put too much thought into it.

JFP: Is replacing all this cam chain stuff pretty labor/parts cost intensive to the point of tearing down the whole motor? I'm thinking about having a more thorugh inspection done to pin point the cause and determine the overall health of the motor with regards to cylinder wear etc. Do worn out timing chains and guides/tensioners etc cause catastrophic failures?

I did pull the original sump recently to replace with a deep sump and there was no plastic debris I could see.

Thanks

Rich

You do not have to tear down the entire engine, but you do need to remove the cam shafts from the cylinder heads, and it does require some special tooling. I've never heard of a worn tensioner or paddle wear pad causing any type of failure, but the engine's do begin to run poorly and will start to throw codes related to the cam timing.

[Hobbes]

Thanks for the insight. I received my new pads today, gaskets, bolts, tensionsers. I was able to get bank 2 back together this evening. The pads were well worn. Judging by the picture, it was a good choice and most likely cause of the ticking noise. I anticipate having it back together this weekend. There were other parts that were well aged that I'm replacing as well, namely, coolant hoses, clutch, flywheel, fuel filter, vacuum lines. The car should purr like a kitten once it's all back together.

Ken

[JFP in PA]

Thanks for the insight. I received my new pads today, gaskets, bolts, tensionsers. I was able to get bank 2 back together this evening. The pads were well worn. Judging by the picture, it was a good choice and most likely cause of the ticking noise. I anticipate having it back together this weekend. There were other parts that were well aged that I'm replacing as well, namely, coolant hoses, clutch, flywheel, fuel filter, vacuum lines. The car should purr like a kitten once it's all back together.

Ken

If you are doing the clutch and flywheel, replace the IMS and RMS, and update your AOS as it is out in the open with the trans out.

[White987S]

Jeff, does oil selection and oil change interval contribute to this wear pattern?

[Hobbes]

Thanks for the insight. I received my new pads today, gaskets, bolts, tensionsers. I was able to get bank 2 back together this evening. The pads were well worn. Judging by the picture, it was a good choice and most likely cause of the ticking noise. I anticipate having it back together this weekend. There were other parts that were well aged that I'm replacing as well, namely, coolant hoses, clutch, flywheel, fuel filter, vacuum lines. The car should purr like a kitten once it's all back together.

Ken

If you are doing the clutch and flywheel, replace the IMS and RMS, and update your AOS as it is out in the open with the trans out.

I appreciate the looking out. I replaced the RMS about 4 years ago and did the AOS a couple ago. When I separated the transmission, I didn't see any oil on either the RMS or IMS, but I know both are prone to failure (RMS did fail). A friend of mine has a 2003 Boxster S and her IMS decided to fail recently. That being my catalyst, I'm looking at doing the IMS on this go around.

[Y2K911]

Just curious! When you replace the IMS on your 2000, please confirm to this 2000 brother that you have a double row. Appreciated!

[JFP in PA]

Jeff, does oil selection and oil change interval contribute to this wear pattern?

Oil selection and shorter intervals will help, but these wear pads should be considered maintenance items, not unlike the brake pads or clutch disc. Eventually, they will need changing.

[JFP in PA]

Just curious! When you replace the IMS on your 2000, please confirm to this 2000 brother that you have a double row. Appreciated!

Won't do you much good as 2000 and 2001 M96 engine's can go either way, some were single row, others dual row. Unfortunately, there is no known way to tell which is in the engine without taking it apart and looking.

[Hobbes]

I agree Jeff. The only way to know is to remove it and look to see which one it is. Unfortunately, I need to pull mine to find out which one it is so I know which IMS bearing to buy. Most likely, I will do the LN Eng upgrade. Unfortunately, their upgrade depends on knowing which one it is first.

[JFP in PA]

I agree Jeff. The only way to know is to remove it and look to see which one it is. Unfortunately, I need to pull mine to find out which one it is so I know which IMS bearing to buy. Most likely, I will do the LN Eng upgrade. Unfortunately, their upgrade depends on knowing which one it is first.

LN is the way to go, there are a lot of newcomers pushing alternatives these days, but the LN product is the only proven unit.

[bcrdukes]

Jeff, does oil selection and oil change interval contribute to this wear pattern?

Oil selection and shorter intervals will help, but these wear pads should be considered maintenance items, not unlike the brake pads or clutch disc. Eventually, they will need changing.

Does this apply to the later 996 models with the 3.6L engine?

[JFP in PA]

Jeff, does oil selection and oil change interval contribute to this wear pattern?

Oil selection and shorter intervals will help, but these wear pads should be considered maintenance items, not unlike the brake pads or clutch disc. Eventually, they will need changing.

Does this apply to the later 996 models with the 3.6L engine?

Good oil and more frequent changes applies to all Porsches, but if you are refering to the five chain cam wear pads, that depends upon the year as not all had them.

[bcrdukes]

Sorry, I should have been more specific. Yes, I was referring to the cam wear pads. My 996 is a 2004 model year with a December 2013 build date.

[JFP in PA]

Sorry, I should have been more specific. Yes, I was referring to the cam wear pads. My 996 is a 2004 model year with a December 2013 build date.

Yours is a three chain motor and will not have these pads.

[Y2K911]

Just curious! When you replace the IMS on your 2000, please confirm to this 2000 brother that you have a double row. Appreciated!

Won't do you much good as 2000 and 2001 M96 engine's can go either way, some were single row, others dual row. Unfortunately, there is no known way to tell which is in the engine without taking it apart and looking.

A bit late getting back to you J-F on your response (merci!) but my car is an early production (Aug 99) 2000, so I feel quite comfortable it is a dual-row. If not, I would be extremely surprised.

At any rate, excellent tip on these wear pads, something else to me mindfull of in the not-so-far term. Salut!

[JFP in PA]

Just curious! When you replace the IMS on your 2000, please confirm to this 2000 brother that you have a double row. Appreciated!

Won't do you much good as 2000 and 2001 M96 engine's can go either way, some were single row, others dual row. Unfortunately, there is no known way to tell which is in the engine without taking it apart and looking.

A bit late getting back to you J-F on your response (merci!) but my car is an early production (Aug 99) 2000, so I feel quite comfortable it is a dual-row. If not, I would be extremely surprised.

At any rate, excellent tip on these wear pads, something else to me mindfull of in the not-so-far term. Salut!

From experience, we have that build date does not seem to come into play on which type of bearing is in the car. We have seen early 2000 cars with single rows in them, and late 2001 cars with dual rows. That is why you need to look before buying parts.

[Y2K911]

Wow! That amazes me greatly (très surprenant, en effet!) and not necesserily good news.

Bon dimanche!

[rbrindley1]

JFP is there any correlation between the VIN's that are covered in the USA IMS Class Action and single-row? This is to say, if one's VIN is in the class the vehicle has a single-row.

[JFP in PA]

JFP is there any correlation between the VIN's that are covered in the USA IMS Class Action and single-row? This is to say, if one's VIN is in the class the vehicle has a single-row.

There has been some supposition that may be the case, but I have not seen any definitive proof of that one way or the other.