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rennbob

Locking Cams Really Necessary on an IMS Replacement?

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So just skip the bearing compound?  Do you ever use it for the IMS at your shop? 

 

Reading the LN instructions and a post by Raby, they say "consider" using bearing compound if there are signs of movement / ovality in the s_haft.   It likely moved a little up/down as there are a few smaller marks 180 degrees from the ones shown.   But then it's gone 100k miles and doesn't look like it has spun in the sha_ft.  I'd prefer not to use compound as it could make installation and removal more difficult.     

 

The bearing is full of oil, no grease.  The inside of the IMS looks OK, no marks.  

 

In the meantime, look what fell out:     :)  

attachicon.gifphoto (5).JPG

 

We have never needed to use bearing compound.

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Cool.   Then in it will go tomorrow AM.  Hoping to get a lot of re-assembly done tomorrow.   

 

Just to confirm, no threadlocker on flywheel, pressure plate, transmission case, CV bolts, right?   There is some "green" on many of the bolts but that might just be corrosion...

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Cool.   Then in it will go tomorrow AM.  Hoping to get a lot of re-assembly done tomorrow.   

 

Just to confirm, no threadlocker on flywheel, pressure plate, transmission case, CV bolts, right?   There is some "green" on many of the bolts but that might just be corrosion...

 

New flywheel and pressure plate bolts should come with thread locker on them; if they don't, I would not hesitate to use Loctite.  Trans case bolts do not need thread locker, but the CV bolts definitely need it.

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I don't see any coating on the new flywheel and PP bolts     I think the parts guy told me he hasn't seen micro-encapsulation of the flywheel bolts in years, and they usually go in dry. 

 

I wish Porsche had a definitive recommendation for this.    I couldn't find anything in my copy of the workshop manuals, but mine is not necessarily up to date.

 

 

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I don't see any coating on the new flywheel and PP bolts     I think the parts guy told me he hasn't seen micro-encapsulation of the flywheel bolts in years, and they usually go in dry. 

 

I wish Porsche had a definitive recommendation for this.    I couldn't find anything in my copy of the workshop manuals, but mine is not necessarily up to date.

 

Strange, we still get them with the coating, but then we buy them in bulk.  In any case, the rule of thumb is simple:  Anything that rotates, vibrates, is time consuming to get at, or can come flying out if the bolts come loose will benefit from Loctite.  As I noted earlier, we Loctite flywheel and pressure plate bolts on every make of car, you really do not want these to come loose.  The axle flange bolts are an excellent example, we find loose ones all the time.  Loctite is cheap, repairing a car that has had a pressure plate or flywheel come loose is not.

  • Like 1

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The new flywheel bolts I recently purchased from Pelican, sold as genuine Porsche, had just a trace of blue stuff down the threads.  I presume this was a light micro-encapsulation.

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The new flywheel bolts I recently purchased from Pelican, sold as genuine Porsche, had just a trace of blue stuff down the threads.  I presume this was a light micro-encapsulation.

 

Correct.

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Here's a pic of my bolts still in the bag.   I don't see any [colored] coating at all.

 

I received these bolts only recently; I had been expecting micro-encapsulated bolts, and to install dry at 19 lbft + 120 deg.   If there is no coating, then adding threadlocker would seem like a good idea.  OTOH, the threadlocker may act as lubricant and render the base torque measurement inaccurate (if Porsche truly meant these to be installed dry).   

 

I will have to call the dealers tomorrow and figure out what's going on.   If the answer is to add threadlocker, I assume I should use blue (med), not red? 

post-48910-0-99732900-1411317985_thumb.j

 

For fun here are the flywheel and PP bolts that came out of the car.   Looks like a green coating on the flywheel bolts, nothing on PP.  

post-48910-0-79692300-1411318309_thumb.j

Edited by rennbob

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Here's a pic of my bolts still in the bag.   I don't see any [colored] coating at all.

 

I receive these bolts only recently; I had been expecting micro-encapsulated bolts, and to install dry at 19 lbft + 120 deg.   If there is no coating, then adding threadlocker would seem like a good idea.  OTOH, the threadlocker may act as lubricant and render the base torque measurement inaccurate (if Porsche truly meant these to be installed dry).   

 

I will have to call the dealers tomorrow and figure out what's going on.   If the answer is to add threadlocker, I assume I should use blue (med), not red? 

attachicon.gifphoto (7).JPG

 

For fun here are the flywheel and PP bolts that came out of the car.   Looks like a green coating on the flywheel bolts, nothing on PP.  

attachicon.gifphoto (8).JPG

 

Blue Loctite would be fine, and I would not worry about the thread locker acting as a lubricant during assembly.

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Hi Rennrob,

 

Don't drive yourself crazy. JFP is giving you sound advise he has done hundreds of these if not a thousand over the years he has been in the business. By calling the dealer you are going to get miss information as you are asking a parts guy that has never worked on a car in his life and if he did he would be a tech. Just my 2 cents.     

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Got pulled away from the project for a little bit.   Now almost everything is back together.  

 

Can anyone confirm the latest torque specs for the 6 M10 nuts that hold the two piece transmission carrier (at the front of the transmission, 4+2 vertical studs into the body) and then the two long bolts that go crosswise-through the transmission carrier and transmission?

 

My copy of the WSM says 48 lb ft for all, but there's a post from Loren that said the through bolts are 33 lb ft?

  

 

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To answer my own question... follow the manual at 48 lb ft for all.   This project is all done and she seems to be running well.   [A little paranoid about the coolant temp, but that can be the subject of a new post].

 

Thanks everyone for all the help! :thumbup:

 

 

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I am doing the LN Engineering IMS retrofit installation now, but after reading half a dozen different tutorials and installation guides, I am still not clear on which of the cams I need to lock on my 2004 C4S. Most of the guides just say 'lock the cams at TDC for cylinder 1'. They don't say if I need to lock just the 2 cams for cyl 1-3 at the rear of the engine near the water pump, or the 2 for cyl 4-6 on the forward starboard side of the engine by the flywheel. or both. The LN tool kit only came with 1 cam lock tool, but I have another cam lock already.

 

I am also reading contradictory information about whether I need to remove just 2 tensioners or also the 3rd one on the top of the engine near the AC.

 

Can anyone confirm or clarify these points?

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I am doing the LN Engineering IMS retrofit installation now, but after reading half a dozen different tutorials and installation guides, I am still not clear on which of the cams I need to lock on my 2004 C4S. Most of the guides just say 'lock the cams at TDC for cylinder 1'. They don't say if I need to lock just the 2 cams for cyl 1-3 at the rear of the engine near the water pump, or the 2 for cyl 4-6 on the forward starboard side of the engine by the flywheel. or both. The LN tool kit only came with 1 cam lock tool, but I have another cam lock already.

 

I am also reading contradictory information about whether I need to remove just 2 tensioners or also the 3rd one on the top of the engine near the AC.

 

Can anyone confirm or clarify these points?

 

 

The first thing you need to do is stop reading anything but the LN IMS retrofit procedure.  A lot of other "shortcut" methods have been posted, but most tend only to lead people into dangerous places with expensive results.  If you do not have the LN procedure, you can find it here : http://lnengineering.com/files/IMSR-Instruction-Warranty.pdf   This is the only procedure I know of that works first time, every time.  Do not vary from it, and you will not have any problems.

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The first thing you need to do is stop reading anything but the LN IMS retrofit procedure.  A lot of other "shortcut" methods have been posted, but most tend only to lead people into dangerous places with expensive results.  If you do not have the LN procedure, you can find it here : http://lnengineering.com/files/IMSR-Instruction-Warranty.pdf   This is the only procedure I know of that works first time, every time.  Do not vary from it, and you will not have any problems.

 

 

Thanks for the fast response JFP - the LN Engineering instructions are the first ones I read but they are too high level and do not say which cams I need to lock and where - see the extract from their instructions below.

I also do not understand the part about "Lock camshaft in head with tensioner accessed from underside of the engine".

I need a more detailed set of instructions (pref with pics) that show exactly which cams to lock and where, and preferably that also show pics of the IMS to crank tensioner and examples of what a worn one would look like. EPS did a very good set of instructions for the Eternal IMS fix, but it is not for the LN bearing.

 

Extract from LN instructions:

 

"6. Use appropriate long cam lock tool for 3-chain or short cam lock tool for 5-chain engine to lock cams prior to removing

chain tensioners. Lock camshaft in head with tensioner accessed from underside of the engine, closest to flywheel.

7. Remove the IMS to crankshaft chain tensioner as well as well the chain tensioner on the cylinder head for which you

have locked the cam. If tensioners are worn or were noisy at startup, replace. NOTE: If the flange does not come off easily, the

bearing is not centered, or you cannot reinstall the flange, then loosen and/or remove the third chain tensioner and verify or

correct camshaft timing."

 

Edited by SpawnyWhippet

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In a 996, "head with tensioner accessed from underside of engine" = bank 1 (left of car)

In other words, lock the crank and lock the bank 1 cams. Remove the cam plugs on bank 1 at the left rear of the head (water pump side). Then it's safe to remove the bank 1 cam tensioner and the IMS tensioner.

Worn tensioner you will see scoring on the movable rod.

Edited by Ahsai
  • Upvote 1

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well, I've been trying for over an hour to lock the cams by the water pump with no success. Cannot get the cam lock tool into both cams at the same time. The lower cam lock fits when the engine is at TDC mark, but the top one only goes in when it is a degree or 2 past TDC

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What are your Durametric cam deviation readings on both banks? Sounds like the bank 1 intake cam is retarded too much...

Edited by Ahsai

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Too late to check now, but I did it a month ago when deciding to install the IMS bearing and they were very close (a lot less than 1 deg off). Assuming it is retarded, how straightforward is it to get them timed now, without pulling the engine?

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The first thing you need to do is stop reading anything but the LN IMS retrofit procedure.  A lot of other "shortcut" methods have been posted, but most tend only to lead people into dangerous places with expensive results.  If you do not have the LN procedure, you can find it here : http://lnengineering.com/files/IMSR-Instruction-Warranty.pdf   This is the only procedure I know of that works first time, every time.  Do not vary from it, and you will not have any problems.

 

 

Thanks for the fast response JFP - the LN Engineering instructions are the first ones I read but they are too high level and do not say which cams I need to lock and where - see the extract from their instructions below.

I also do not understand the part about "Lock camshaft in head with tensioner accessed from underside of the engine".

I need a more detailed set of instructions (pref with pics) that show exactly which cams to lock and where, and preferably that also show pics of the IMS to crank tensioner and examples of what a worn one would look like. EPS did a very good set of instructions for the Eternal IMS fix, but it is not for the LN bearing.

 

Extract from LN instructions:

 

"6. Use appropriate long cam lock tool for 3-chain or short cam lock tool for 5-chain engine to lock cams prior to removing

chain tensioners. Lock camshaft in head with tensioner accessed from underside of the engine, closest to flywheel.

7. Remove the IMS to crankshaft chain tensioner as well as well the chain tensioner on the cylinder head for which you

have locked the cam. If tensioners are worn or were noisy at startup, replace. NOTE: If the flange does not come off easily, the

bearing is not centered, or you cannot reinstall the flange, then loosen and/or remove the third chain tensioner and verify or

correct camshaft timing."

 

 

 

 

IMS_and_bank_1_chain_tensioners.jpg

 

It is sounding like your cam timing is already off if you cannot get the cam locking tool in place.  Try rotating the engine 360 degrees (clockwise only) by hand and see if the cams line up better.  If they do not, you may be facing a cam allocation procedure.

  • Upvote 1

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Came at it with a fresh head after a night of sleep and got the cam tool into place after just 15 mins.

I removed the coolant hoses that run in front of the cam plugs so I could see what I was doing, then jiggled the crank around the TDC point until the cam slots aligned and finally got the tool in place. Turns out that they align when the TDC crank mark is about 2 degrees past the mark on the engine case.

 

I could not tighten the allen head bolt that came with the LN kit, so I cut down and used a 13mm bolt and a cordless ratchet to bolt the tool to the engine case.

 

Onto the tensioners... let battle commence.

Edited by SpawnyWhippet

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