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LN Engineering Retrofit Kit Instructions - Rev 18 Jan 14. state the following:


Step 6. Lock camshaft in head with tensioner accessed from underside of the engine, closest to flywheel.


Which head? Challenge is that there exists two tensioners that can (kind of) match to above description.


When looking towards the flywheel, about 10 inches left from the IMS flange, under the engine, you will find a horizontally aligned tensioner. This should be the IMS chain tensioner and this one is closest to flywheel, however it is not located "in head".


When looking towards the flywheel, about 15 inches right from the IMS flange, under the engine, you will find a vertically aligned tensioner. This should be the cylinder 1-3 camshaft chain tensioner and it is located beneath bank 1, second closest tensioner to flywheel.


Now, which one of the banks should I lock? Look again at the instruction text and notice that both are close to flywheel and underside of the engine :-)



Step 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.


Well, this depends on which bank I locked.



My pick would be to lock bank 1. After all bank 1 chain is directly coupled with the flywheel side of the IMS. Then remove both tensioners visible on my image.


My plan is to follow LN's instructions by the book and I do understand that I am solely responsible of the outcome. The only exception is that I'd like to lock all my cams (not only bank 1 but also bank 2), I can fabricate another cam lock tool, I assume this is safe thing to do.


Would you agree?




PS. Would be great if next revision would add wording "lock bank 1" instead of "lock camshaft in head with tensioner closest to flywheel"

post-93239-0-99899600-1397161003_thumb.j

Edited by Domiac

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Unfortunately the instructions must be applicable for both 911 and Boxster variants. You can't say "the driver's side of the motor" as that will be bank 2 of a US spec Boxster but bank 1 of a US spec 911.

If LN said "lock bank 1", then they would have to explain to a novice exactly what "bank 1" refers to .

I've been pulling my hair trying to figure this out myself, and have been working up an "expanded" version of the LN instructions.

Bank 1 (cylinders 1,2,3) has the cam chain tensioner at the bottom, near the flywheel. Bank 2 (cylinders 4,5,6) has the cam chain tensioner under the AC compressor, near the "front" of the motor (serpentine belt pulley side). The other tensioner you indicate is for the chain between the crankshaft and the IMS.

You lock the bank 1 cams at the "front" of the motor (serp belt pulley side) even though the corresponding bank 1 cam chain tensioner is at the back of the motor, near the flywheel.

What's your year? Is it 5 chain or 3 chain?

  • Upvote 1

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Unfortunately the instructions must be applicable for both 911 and Boxster variants. You can't say "the driver's side of the motor" as that will be bank 2 of a US spec Boxster but bank 1 of a US spec 911.

If LN said "lock bank 1", then they would have to explain to a novice exactly what "bank 1" refers to .

I've been pulling my hair trying to figure this out myself, and have been working up an "expanded" version of the LN instructions.

Bank 1 (cylinders 1,2,3) has the cam chain tensioner at the bottom, near the flywheel. Bank 2 (cylinders 4,5,6) has the cam chain tensioner under the AC compressor, near the "front" of the motor (serpentine belt pulley side). The other tensioner you indicate is for the chain between the crankshaft and the IMS.

You lock the bank 1 cams at the "front" of the motor (serp belt pulley side) even though the corresponding bank 1 cam chain tensioner is at the back of the motor, near the flywheel.

What's your year? Is it 5 chain or 3 chain?

Sorry, forgot to mention that my car is 996, 2004, 3.6L, 3-chain. The image on this post is done by me and it is from my engine.

Yes, one should never use "driver's side" or "left bank" or such, that is quite ambiguous.

Problem here is that LN does not use "bank" terminology at all. Read carefully what I wrote to my initial post using bold font, it says it all :-)

I was quite certain that I got it right but your response validated that my assumptions were right. Background to this question is that I do like to double check things through this forum before taking action, especially when we are talking of IMS change.

Thank you!

Edited by Domiac

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LN Engineering Retrofit Kit Instructions - Rev 18 Jan 14. state the following:
Step 6. Lock camshaft in head with tensioner accessed from underside of the engine, closest to flywheel.
Which head? Challenge is that there exists two tensioners that can (kind of) match to above description.
When looking towards the flywheel, about 10 inches left from the IMS flange, under the engine, you will find a horizontally aligned tensioner. This should be the IMS chain tensioner and this one is closest to flywheel, however it is not located "in head".
When looking towards the flywheel, about 15 inches right from the IMS flange, under the engine, you will find a vertically aligned tensioner. This should be the cylinder 1-3 camshaft chain tensioner and it is located beneath bank 1, second closest tensioner to flywheel.
Now, which one of the banks should I lock? Look again at the instruction text and notice that both are close to flywheel and underside of the engine :-)
Step 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.
Well, this depends on which bank I locked.
My pick would be to lock bank 1. After all bank 1 chain is directly coupled with the flywheel side of the IMS. Then remove both tensioners visible on my image.
My plan is to follow LN's instructions by the book and I do understand that I am solely responsible of the outcome. The only exception is that I'd like to lock all my cams (not only bank 1 but also bank 2), I can fabricate another cam lock tool, I assume this is safe thing to do.
Would you agree?
PS. Would be great if next revision would add wording "lock bank 1" instead of "lock camshaft in head with tensioner closest to flywheel"

The instructions are ambiguous due to the same engine used in both the Boxster and 996. You want to lock Bank #1 (cylinders 1,2,3). The IMS tensioner is the same one indicated in the photo you included. A lot of people fab a second cam locking tool just to be safe, but it is not absolutely a requirement. If you completely remove the tensioners, do not mix them, they are not all the same. You should also replace the aluminum sealing ring on each tensioner released or removed to prevent future oil leaks.

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Actually it became clear to me once I inspected one of my workshop manuals, here's an image for everyone who are interested of. You can interpret this image just like you would look 996 from the back of the car, seeing serpentine right in front of you. Another better way is to say that on the image, bank 1 is on the left and bank 2 on the right.

post-93239-0-97733600-1397165291_thumb.j

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Actually it became clear to me once I inspected one of my workshop manuals, here's an image for everyone who are interested of. You can interpret this image just like you would look 996 from the back of the car, seeing serpentine right in front of you. Another better way is to say that on the image, bank 1 is on the left and bank 2 on the right.

Nice photos in your threads Domiac. Thought this will compliment your 2D diagram.

post-5282-0-63241800-1397248697_thumb.jp

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After installing new bearing, IMS has moved somewhat further away from the flywheel side, I assume this is actually how it should work. During the installation I started using my dead blow hammer easier so that the IMS secures to the other side and then later applied more force so that my new bearing started to go in and finally I could install the snap ring.

Just wanting to make sure my two images (before and after) look normal. Thank you!

post-93239-0-46823600-1397509492_thumb.j

Edited by Domiac

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After installing new bearing, IMS has moved somewhat further away from the flywheel side, I assume this is actually how it should work. During the installation I started using my dead blow hammer easier so that the IMS secures to the other side and then later applied more force so that my new bearing started to go in and finally I could install the snap ring.

Just wanting to make sure my two images (before and after) look normal. Thank you!

That looks fine. The entire IMS shaft can move back and forth a bit, so don't be overly concerned about that.

  • Upvote 1

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After installing new bearing, IMS has moved somewhat further away from the flywheel side, I assume this is actually how it should work. During the installation I started using my dead blow hammer easier so that the IMS secures to the other side and then later applied more force so that my new bearing started to go in and finally I could install the snap ring.

Just wanting to make sure my two images (before and after) look normal. Thank you!

That looks fine. The entire IMS shaft can move back and forth a bit, so don't be overly concerned about that.

This could be completely bogus and I am not going to do this, but feel free to wonder the following..

When you tap new bearing in, IMS moves slightly away from the flywheel side. After we torque IMSB stud nut on step 22, IMS cannot move back to its original position anymore. However, before step 22 when IMSB flange is secured but IMSB stud nut is still loose, why don't we reinstall tensioners and perhaps even remove cams + crank lock and rotate engine a few times to let IMS, chains and paddles settle better before continuing with the step 22?

Once again, I do not suggest that anyone tries this, I am simply trying to learn something :lightbulb: It feels a bit strange to move IMS a bit (manually) and then secure it to such place. Can be that it is simply the price that one has to pay when doing bearing upgrades.

A reminder of the steps involved here are (rev 18 jan 14):

20. "You are now ready to install the new hub flange. Inspect seal for damage as well as bore in the block for any
imperfections that might cause the new seal or flange to leak. Take care not to damage o-ring located in new hub flange, using an o-ring lubricant on seal to facilitate easy installation. Once new flange is started, use three (3) M6X25 bolts, tightening in a star pattern slowly to draw in the new hub flange in."

21. "Once home, remove M6X25 bolts and replace with new micro-encapsulated bolts. Use flange sealant on bottom of head of the bolt. Torque specs 7.5 ft/lb (10 Nm)."

22. "The center bearing support 12 point nut can be installed and torqued to the factory spec (currently 7.5 ft/lb). Use flange sealant (Loctite 574 or Curil T) on bottom of head of the bolt and use wicking (green) Loctite on the exposed threads of the center bearing support/stud and 12 point nut. If the small o-ring is damaged or leaks, the use of flange and thread sealants should prevent a leak."
23. "Reinstall chain tensioners with new sealing rings and torque to the factory spec of 59 ft/lb."
Edited by Domiac

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After installing new bearing, IMS has moved somewhat further away from the flywheel side, I assume this is actually how it should work. During the installation I started using my dead blow hammer easier so that the IMS secures to the other side and then later applied more force so that my new bearing started to go in and finally I could install the snap ring.

Just wanting to make sure my two images (before and after) look normal. Thank you!

That looks fine. The entire IMS shaft can move back and forth a bit, so don't be overly concerned about that.

This could be completely bogus and I am not going to do this, but feel free to wonder the following..

When you tap new bearing in, IMS moves slightly away from the flywheel side. After we torque IMSB stud nut on step 22, IMS cannot move back to its original position anymore. However, before step 22 when IMSB flange is secured but IMSB stud nut is still loose, why don't we reinstall tensioners and perhaps even remove cams + crank lock and rotate engine a few times to let IMS, chains and paddles settle better before continuing with the step 22?

Once again, I do not suggest that anyone tries this, I am simply trying to learn something :lightbulb: It feels a bit strange to move IMS a bit (manually) and then secure it to such place. Can be that it is simply the price that one has to pay when doing bearing upgrades.

You could do that, but it is not really necessary. First of all, the IMS shaft will relocate itself just fine all by itself when the engine starts to turn over for its first restart. Secondly, we normally flush out the hydraulic tensioner's if they are not being replaced, and then hand pump them in clean oil just prior to reinstalling them with new sealing washers, so they have some tension on them at first start. Third, we normally pull the fuel pump relay out (so that the car won't start), and then spin it over with the starter until it develops oil pressure, which also allows everything to settle. Then, after one more inspection for anything that was missed, put the relay back in and light the car off.

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This could be completely bogus and I am not going to do this, but feel free to wonder the following..

When you tap new bearing in, IMS moves slightly away from the flywheel side. After we torque IMSB stud nut on step 22, IMS cannot move back to its original position anymore. However, before step 22 when IMSB flange is secured but IMSB stud nut is still loose, why don't we reinstall tensioners and perhaps even remove cams + crank lock and rotate engine a few times to let IMS, chains and paddles settle better before continuing with the step 22?

Once again, I do not suggest that anyone tries this, I am simply trying to learn something :lightbulb: It feels a bit strange to move IMS a bit (manually) and then secure it to such place. Can be that it is simply the price that one has to pay when doing bearing upgrades.

You could do that, but it is not really necessary. First of all, the IMS shaft will relocate itself just fine all by itself when the engine starts to turn over for its first restart. Secondly, we normally flush out the hydraulic tensioner's if they are not being replaced, and then hand pump them in clean oil just prior to reinstalling them with new sealing washers, so they have some tension on them at first start. Third, we normally pull the fuel pump relay out (so that the car won't start), and then spin it over with the starter until it develops oil pressure, which also allows everything to settle. Then, after one more inspection for anything that was missed, put the relay back in and light the car off.

Interesting. I was under the impression that IMS sprocket has a rigid connection to IMS which has a rigid connection to IMSB which has a rigid connection to IMSB stud which has a rigid connection to IMSB flange (because of the flange nut) which has a rigid connection to crankcase. It must be that something between, or some other component, moves.

Yes, I've seen your and other people's instructions on how to clean and prime tensioners with new oil, reinstall with new washer. I also plan to build oil pressure by keeping the spark plugs and relay out when I crank the engine for 10 seconds, wait a few seconds and crank another 10 seconds before doing it for real. All these are on my TODO list. Thanks again for reminding though!

post-93239-0-38320600-1397586897_thumb.j

Edited by Domiac

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I assume that once you crank the engine, IMS may move a bit back towards flywheel side and this also forces IMS bearing + stud + nut to move as they are all connected to each other components. Perhaps it is best to stop contemplating this too deeply. Thanks for the comments though!

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$_57.JPG

While you may not have noticed it, when you were prepping for the extracting the old bearing, you pulled the shaft slightly towards the flywheel. When you hammered in the new bearing, it moved slightly the other way, but it will straighten itself out.

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Since we are on the subject of the LN instructions... I want to ask about STEP 16 on the use of Loctite bearing mount.

Is this needed only if the IMS shaft has some ovality, or is it recommended no matter what so the outer race doesn't spin relative to the IMS shaft? I have seen some pictures of bearings that were spinning inside the shaft and you can see the wear marks on the outer race. The next hurdle is selecting the proper bearing mount since each one is tuned for a specific gap between the outer race and tube. The instructions have no specification for ovality and only say to consider using bearing mount.

When looking at the Bentley Publishers IMS replacement youtube video (time=5:38), there appears to be grease on the outer race just prior to hammering it in which surprised me and seems to contradict the instructions (I realize the LN Instructions supersede all else).

BTW, I asked LN the same question but since I am not an authorized installer, they will not answer any of my questions.

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Since we are on the subject of the LN instructions... I want to ask about STEP 16 on the use of Loctite bearing mount.

Is this needed only if the IMS shaft has some ovality, or is it recommended no matter what so the outer race doesn't spin relative to the IMS shaft? I have seen some pictures of bearings that were spinning inside the shaft and you can see the wear marks on the outer race. The next hurdle is selecting the proper bearing mount since each one is tuned for a specific gap between the outer race and tube. The instructions have no specification for ovality and only say to consider using bearing mount.

When looking at the Bentley Publishers IMS replacement youtube video (time=5:38), there appears to be grease on the outer race just prior to hammering it in which surprised me and seems to contradict the instructions (I realize the LN Instructions supersede all else).

BTW, I asked LN the same question but since I am not an authorized installer, they will not answer any of my questions.

Step 16 is a fix for a loose bearing or out of round shaft. The bearing itself should be a press fit, hence the removal and installation processes. But sometimes you find really loose bearings in cars, which is when you would use the Loctite.

The bearing goes in dry; if cold enough, no lubricant is really needed.

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.

Secondly, we normally flush out the hydraulic tensioner's if they are not being replaced, and then hand pump them in clean oil just prior to reinstalling them with new sealing washers, so they have some tension on them at first start.

This "flushing" is boiling them out in a pan of Marvel Mystery Oil, right?

I'm waiting for warm weather so the rest of the car is warm compared to the IMSB from the freezer.

Edited by Dennis Nicholls

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.

Secondly, we normally flush out the hydraulic tensioner's if they are not being replaced, and then hand pump them in clean oil just prior to reinstalling them with new sealing washers, so they have some tension on them at first start.

This "flushing" is boiling them out in a pan of Marvel Mystery Oil, right?

I'm waiting for warm weather so the rest of the car is warm compared to the IMSB from the freezer.

If they are nasty we put them in a pan of very warm Mystery oil or in an ultrasonic cleaner; otherwise we just flush them with clean oil.

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Regarding possible the movement of the shaft + stud + nut, once you start the car after an IMS upgrade, I am starting to understand better why people put green wicking Loctite to the threads and Curil T under the nut.

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Just a success note: The car is a 2003 996 C4S with 77K miles which I bought back in December with very little maintenance history (CarFax said the RMS was done in 2004), and a long list of issues topped by a clutch past borrowed time. With a number of things keeping me from tackling the issues head-on with more time, today I finally got the old IMS bearing out with no issues - and it's pristine with both seals intact. However, lying on my back under the car while doing this, as the IMS relieved itself from the crankcase - about a cup of oil glopped onto my chest. Scratch one tee-shirt.

The 2-Do list: install the upgraded IMS hardware, replace the rear main seal, install the new lightweight flywheel and clutch package, reinstall the rear axles, marry the tranny to the engine, fill tranny fluid, install all of the FWD hardware, install new engine mounts, new water pump and thermostat, and the list goes on and on.

Thanks to all you guys for the threads, posts, How-to's and DIY instructions. I take a stand at what dealers charge for shop rates these days, and at a $15/hr minimum wage rate, no more fast food either!

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Lets keep this thread for IMSB but one tip I wish to mention.. As your car is 11 years old, be sure to add 996-106-226-52 to your list. Cost $8 and dead simple to change. Located right from the alternator / oil filler tube. Connects cooling tubes into AOS. My connection piece literally disintegrated to my hands when I accidentally touched it during my engine drop. Use screwdriver or such to separate tubes a bit from the connector piece and spray some silicon inside there, then the connector piece comes out a lot easier and without fear that it breaks and you get plastic pieces in your cooling system.

See

http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=&make=&please_wait=N&forumid=&threadid=&command=DWsearch&description=996-106-226-52

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  • Similar Content

    • By RobT
      I'm new to this forum and the Boxster community! I recently bought a used 2005 Porsche 987 Boxster S with 92,000 miles. The previous owners have done the maintenance but did not address the IMS bearing issue.

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      Has anyone had experience removing the 4-6 bank chain adjuster on a '05 987 Boxster? A more fundamental question might be: do I actually need to remove the 4-6 bank chain adjuster to install the new IMS bearing?

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