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Old 11-23-2014, 08:52 AM   #1
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Chain rattle at 3K - Do they all do it?

Let me start by saying that I have absolutely no chain rattle at start-up. I know that is a common problem, and there are many past posts on that issue.

My 986S with a 2006 OEM engine (3 chain) has a lot of chain rattle right at 3000 RPM, that only occurs in a narrow window from about 2800 - 3200 RPM. I believe this is where the cam timing advance kicks in.

This is nothing new on my engine. It has been doing this for the 4 years that I have owned it, and quite a few track days. Many oil changes during that time have all been very clean, with only an occasional small plastic spec (chain guides I presume). I am now running without the heavy carpet mat over the engine cover, which makes the noise a bit more prevalent.

Do they all do it? Is there a fix to improve the chain tensioners?

Thanks for any info.
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Old 11-23-2014, 09:01 AM   #2
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I am doing an engine rebuild now -so perhaps a little paranoid or wise.
One thing I learned is do not down-play 'noises' .Thoroughly diagnose them with a competent Indie early. It isn't just the cost of a timing chain mechanism failure -it is the widespread collateral damage that will break your wallet.The noise you hear may be chains flailing because of inadequate tension.Metal-to-metal contact inside the case could be either bad or disastrous.
I think the seals on the variocam tensioner solenoids were upgraded but that was way earlier than your build. Let us know what you find?
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Old 11-23-2014, 09:26 AM   #3
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What year car? What version DME?
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Old 11-23-2014, 02:38 PM   #4
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This car is a 2002 with an OEM engine replacement by Porsche dealer in 2006 by the previous owner. So the DME is a 2002 version. The engine is confirmed to be the large single bearing unit, which I believe means that it is a 3 chain.

Thanks.
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Old 11-23-2014, 04:32 PM   #5
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Sounds like you have a stretched main chain, or maybe two. These drive the cams from the IMS and are known to stretch.
We have master linked chains and can change these chains without full engine disassembly.
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Old 11-24-2014, 11:44 AM   #6
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Quote:
Originally Posted by LAP1DOUG View Post
This car is a 2002 with an OEM engine replacement by Porsche dealer in 2006 by the previous owner. So the DME is a 2002 version. The engine is confirmed to be the large single bearing unit, which I believe means that it is a 3 chain.

Thanks.
If the engine is properly controlled by the cars original DME then the engine would have to be a 5-chain version.
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Old 11-24-2014, 06:43 PM   #7
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Rattle

Listen to what Jake is saying there are few as knowledgeable !!!!
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Old 11-24-2014, 10:10 PM   #8
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Quote:
Originally Posted by Jake Raby View Post
Sounds like you have a stretched main chain, or maybe two. These drive the cams from the IMS and are known to stretch.
We have master linked chains and can change these chains without full engine disassembly.
If the main chain(s) are stretched, wouldn't this show up when you checked the camshaft deviation?

Lap1doug - have you any idea what your camshaft deviations are?
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Old 11-24-2014, 11:20 PM   #9
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If the main chain(s) are stretched, wouldn't this show up when you checked the camshaft deviation?

Lap1doug - have you any idea what your camshaft deviations are?
No, to date I haven't seen an engine with stretched chains show up in cam deviations.
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Old 11-26-2014, 10:29 AM   #10
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Thanks for the info. guys. Jake I didn't know you did anything other than complete engine rebuilds at your shop. I will contact you to see if I can bring my car up to Cleveland sometime after the holidays.

Thanks again, and Happy Thanksgiving all.
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Old 11-26-2014, 10:40 AM   #11
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Originally Posted by LAP1DOUG View Post
Thanks for the info. guys. Jake I didn't know you did anything other than complete engine rebuilds at your shop. I will contact you to see if I can bring my car up to Cleveland sometime after the holidays.

Thanks again, and Happy Thanksgiving all.
We have three divisions here, one side of the house does engine reconstructions, the other does deep internal repairs, and the other develops and evaluates components and engine designs.

The repair side is slammed through the winter, we are scheduling early spring repairs now, so make sure you email jud@rabyenginedevelopment.com to set up an appointment.

If you are close, and if this is what I believe it is we MIGHT be able to work it in early, just because we get held up around the holidays with some projects, because people in the supply chain want time off! ( Bah Humbugg!)
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Old 12-03-2014, 11:23 AM   #12
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So are you suppling SSF with your master linked chains yet?
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