Start Up Rattle - Part Upgrade to Eliminate

[Seadweller]

Greetings!

My '98 base w/ Tip is going into the shop in a couple of weeks for some maintenance items, and while it's there, I was going to have an update I've read about installed that seems to eliminate the start up rattle issue.

I believe the part is updated from the original by the addition of some sort of spring that holds pressure on the tensioners. For some reason, I haven't been able to find it via search.

Could someone please let me know what parts I need for this upgrade, and is it truly compatible with my '98?

Has anyone done the upgrade and arrived at an acceptable outcome?

Thanks!

[JFP in PA]

Depends upon how deep you want to dive on this one. Startup clatter can be caused by your lifters, hydraulic chain tensioners, chain pad wear, cold start piston slap, bore scoring, or even stretched timing chains.

You need to isolate the source before even thinking about fixing it, as you can throw a lot of part and labor $ at it, and still have the issue if you guess wrong.

[Stl-986]

Never heard of an "update to eliminate rattle" Are you talking the engine, front of car, exhaust, what?

[Dion986S]

I have the exact same thing happen on my 2002S. I had my Wife start the car while I was laying under it. It's not the exhaust, and it only lasts for about 2 seconds. I also assumed it was probably the tensioners because it reminded me of the same sounds when my oil fed tensioners on my aircooled 3.2 would deflate and make the same chain sound at startup. I was going to start there as well.

[Oldcarguy]

Originally Posted by Seadweller

Greetings!

My '98 base w/ Tip is going into the shop in a couple of weeks for some maintenance items, and while it's there, I was going to have an update I've read about installed that seems to eliminate the start up rattle issue.

I believe the part is updated from the original by the addition of some sort of spring that holds pressure on the tensioners. For some reason, I haven't been able to find it via search.

Could someone please let me know what parts I need for this upgrade, and is it truly compatible with my '98?

Has anyone done the upgrade and arrived at an acceptable outcome?

Thanks!

I think you’re talking about the oil pressure relief valve with the updated bevel and spring. There is no additional spring that holds pressure on the tensioners. No guarantee that this will cure the startup valve train chain rattle. Just Google ‘986 oil pressure relief valve’ for more info.

[911monty]

He is talking about the Intermediate shaft to crank chain tensioner with the external spring that Porsche upgraded in 01-02, helps prevent tensioner relaxing/collapsing while sitting. My 98 has one installed should work fine in yours.

Edit This part https://www.pelicanparts.com/More_Info/99610518058.htm?pn=996-105-180-58-M100&SVSVSI=1049&DID=13597

[lkchris]

Originally Posted by Oldcarguy

I think you’re talking about the oil pressure relief valve with the updated bevel and spring. There is no additional spring that holds pressure on the tensioners. No guarantee that this will cure the startup valve train chain rattle. Just Google ‘986 oil pressure relief valve’ for more info.

He could be.

Many don't know that at your Porsche dealer you can purchase either just a filter element or a complete assembly consisting of the plastic container with (obviously) a new relief valve plus of course the filter element. Not a bad thing to do periodically.

[ike84]

Originally Posted by lkchris

He could be.



Many don't know that at your Porsche dealer you can purchase either just a filter element or a complete assembly consisting of the plastic container with (obviously) a new relief valve plus of course the filter element. Not a bad thing to do periodically.

Chris, the oil pressure relief valve is different from the filter bypass spring in the filter housing which you're talking about. Look at a diagram of the oil flow for 986 and you will see the relief valve at the level of the pump. It's a cap over spring assembly that Porsche updated, and the newer part helps improve oil flow during cold startups with high oil pressure (that's my understanding of it at least). Ttgator did a good video of the swap with part numbers (adds 5 min to your next oil change)

Sent from my POCOPHONE F1 using Tapatalk

[ike84]

Originally Posted by 911monty

He is talking about the Intermediate shaft to crank chain tensioner with the external spring that Porsche upgraded in 01-02, helps prevent tensioner relaxing/collapsing while sitting. My 98 has one installed should work fine in yours.

Edit This part https://www.pelicanparts.com/More_Info/99610518058.htm?pn=996-105-180-58-M100&SVSVSI=1049&DID=13597

Hey Monty - do you have any info on that part or a diy for installation? This is the first I've ever heard of it.

Sent from my POCOPHONE F1 using Tapatalk

[911monty]

Originally Posted by ike84

Hey Monty - do you have any info on that part or a diy for installation? This is the first I've ever heard of it.

Sent from my POCOPHONE F1 using Tapatalk

This link should get you started. I think the TSB is in here.

Chain ramp replacement...gaining access?

As far as changing the tensioner, some have reported no issues just locking the crank on the 5 chain engine. I do not see any reason that would not be sufficient. However I do not like taking chances and I have the IMSB tools so I also locked the bank 1 cams which JFP recommends.

[Seadweller]

Originally Posted by JFP in PA

Depends upon how deep you want to dive on this one. Startup clatter can be caused by your lifters, hydraulic chain tensioners, chain pad wear, cold start piston slap, bore scoring, or even stretched timing chains.

You need to isolate the source before even thinking about fixing it, as you can throw a lot of part and labor $ at it, and still have the issue if you guess wrong.

Thanks JFP, the car has 37K miles on it, so would that rule out some of what you have listed as possible causes?

[Seadweller]

Originally Posted by 911monty

He is talking about the Intermediate shaft to crank chain tensioner with the external spring that Porsche upgraded in 01-02, helps prevent tensioner relaxing/collapsing while sitting. My 98 has one installed should work fine in yours.

Edit This part https://www.pelicanparts.com/More_Info/99610518058.htm?pn=996-105-180-58-M100&SVSVSI=1049&DID=13597

I understand there's 3 tensioners, but can just this one part be replaced/updated, and did it cure the rattle?

[Seadweller]

Originally Posted by ike84

Ttgator did a good video of the swap with part numbers (adds 5 min to your next oil change)

Sent from my POCOPHONE F1 using Tapatalk

I can't locate this video, so would you be kind enough to provide a link?

[Radman]

Originally Posted by Seadweller

I understand there's 3 tensioners, but can just this one part be replaced/updated, and did it cure the rattle?

Fair warning that the part says it is only applicable to 2001 and newer.

[JFP in PA]

Originally Posted by Seadweller

Thanks JFP, the car has 37K miles on it, so would that rule out some of what you have listed as possible causes?

A lot of simple diagnostics: Pull the sump cover and look for evidence of the plastic from the chain pads, bore scope the cylinders looking for signs of scoring, run cam deviation values, etc., etc.

[ike84]

Originally Posted by Seadweller

I can't locate this video, so would you be kind enough to provide a link?

I can't seem to find it either but here are the part numbers. Ignore the TB housing.

Sent from my POCOPHONE F1 using Tapatalk

[ike84]

Originally Posted by Radman

Fair warning that the part says it is only applicable to 2001 and newer.

Rad is right. I read that tsb, it actually specifically says that the parts are not to be intermixed. There are certainly a few people who have done that swap though and it seems like no one killed their motor in doing my so.

I'm all for updating parts, but with the available evidence this seems a bit sketchy to do.

This may be a silly thing to say, but who cares about startup chain rattle? If the ramps are good, your cam deviations are good, and the oil pressures are fine I personally think this is a non-issue.

Sent from my POCOPHONE F1 using Tapatalk

[Seadweller]

Originally Posted by ike84

This may be a silly thing to say, but who cares about startup chain rattle? If the ramps are good, your cam deviations are good, and the oil pressures are fine I personally think this is a non-issue.

Sent from my POCOPHONE F1 using Tapatalk

I would tend to agree, and perhaps I'd feel more comfortable if I knew exactly what was causing the rattle. Is it isolated to the chains themselves, or is it the chains slapping against the ramps? I would think over time, if the chains are slapping the ramps, it would cause excessive/premature wear, and possibly even failure.

[JFP in PA]

Originally Posted by ike84

Rad is right. I read that tsb, it actually specifically says that the parts are not to be intermixed. There are certainly a few people who have done that swap though and it seems like no one killed their motor in doing my so.

I'm all for updating parts, but with the available evidence this seems a bit sketchy to do.

This may be a silly thing to say, but who cares about startup chain rattle? If the ramps are good, your cam deviations are good, and the oil pressures are fine I personally think this is a non-issue.

Sent from my POCOPHONE F1 using Tapatalk

This oil pump spring and valve upgrade was implemented to address low oil pressure problems at idle when fully warmed up and using their "recommended" piss thin oils. It was never designed to address any cold start up noise issues.

[911monty]

Originally Posted by ike84

Rad is right. I read that tsb, it actually specifically says that the parts are not to be intermixed. There are certainly a few people who have done that swap though and it seems like no one killed their motor in doing my so.

I'm all for updating parts, but with the available evidence this seems a bit sketchy to do.

This may be a silly thing to say, but who cares about startup chain rattle? If the ramps are good, your cam deviations are good, and the oil pressures are fine I personally think this is a non-issue.

Sent from my POCOPHONE F1 using Tapatalk

Just how silly? Who cares? Apparently Porsche engineers did. In fact per the following technical bulletin the change was made to specifically address noise.

5 chain.pdf

As far as sketchy goes, The changes per the technical bulletin was moving from a roller to a tooth type chain requiring a change to the crank and IMS drive sprockets, these obviously are not interchangeable and the TSB makes sure to address this. The change to the Tensioner was to add an external spring to help during startup. Even though not mentioned in the Technical bulletin there were improvements to the chain paddle. However the point the chain tensioner contacts on the backside of the paddle that has no interaction with the tooth type chain remained the same black plastic pad in the same location.

Personally I see this as an mechanical improvement unlike a 1200 cfm square bore .