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Greetings/IMS failure


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The teeth are about 3.5 mm tall. On three chain engines they can jump more easily. 5 chain engines it is much less likely. It is still worth removing the cam caps to verify the timing marks regardless.

Yes, if the timing is off, you can have piston/valve contact and possible meltdown.

Here is the cylinder designation for you:

cylinders.png

Cool, how do I know how many chains I have? And, do you have a diagram showing where the caps are? I would have to manually pull the engine to TDC to get the cams lined up.... I guess I would feel it if it was locking up...

The caps are two bright green rubber plugs that are on one end of the cylinder heads. You will find one set on each end of the engine, they look like this:

Pic139.jpg

I really need to caution you on attempting to rotate the engine with the IMS bearing out; you are tap dancing in a mine field by doing this. If the engine has not jumped time yet, it most likely will when you attempt to rotate it…………..

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Thanks, JFP I appreciate you taking the time to answer my questions. So, how "tall" are the teeth on the sprockets and how easy is it for them to jump? We are pretty sure timing was good when we started to disassemble, and other than the releasing of the tensioners there hasn't been any movement.

It's not my call, but my friend wants to install the new bearing. I will insist we check the marks on the cams before we fire it up. I deduce from what you say that if the timing is off there can/will be piston/valve contact.

One more question: Standing behind the car looking forward, which cylinder is #1?

The M96/97 is an "interference motor", meaning the valves will contact the pistons if the cam timing is off. This is what you are dealing with at the IMS bearing sprocket:

imsinstalled32boxster.jpg

This is the chain layout at the cams (five chain motor):

Pic09.jpg

Edited by JFP in PA
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I really need to caution you on attempting to rotate the engine with the IMS bearing out; you are tap dancing in a mine field by doing this. If the engine has not jumped time yet, it most likely will when you attempt to rotate it…………..

Oh no, I realize that. I have NO intention of moving it a millimeter until the bearing AND the tensioners are back in. Just trying to evaluate my odds of still being in time at this point, and how to proceed once we get a bearing back in there. Thanks.

Edited by Oscarvan
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The outer race is out.

Plan is to put the new bearing in, reinstall the tensioners, then pull the plugs and turn the crankshaft, by hand, two revolutions.

Question: If there was interference would I be able to move through it by hand? (Plugs out....)

Edited by Oscarvan
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The outer race is out.

Plan is to put the new bearing in, reinstall the tensioners, then pull the plugs and turn the crankshaft, by hand, two revolutions.

Question: If there was interference would I be able to move through it by hand? (Plugs out....)

Yes, the “interference” may have already "clearanced" itself by bending the valves out of the way, which is why we (and others) always bore scope one of these before doing anything..................

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If you pop off the cam plugs you should be able to get an idea whether the timing has shifted. At TDC the grooves should be vertical. I have pictures of them on my DIY IMS AOS thread on Rennlist. 996.

Sorry, where is that?

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The groove are on the crank pulley line up with the OT line in the case.

Unless you mean the DIY walkthrough, some honest advice for you. After re-reading this thread we have been guiding you step by step... I suggest you get your hands on a work shop manual and read through it, otherwise this is going to take a very long time... no problem either way, but things would make a lot more sense and much less chance for error if you read through that manual as opposed to stitching the pieces together from this thread.

Edited by logray
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This entire thing has "bad idea" written all over it. You have no idea if the engine jumped time, no idea if you have bent valves, no idea how much metal has been sent around the engine, and you want to stuff a new IMS bearing into a damaged IMS shaft?

As others here who are knowledgeable have stated, all of this is especially pointless if you haven't even borescoped each cylinder.

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This entire thing has "bad idea" written all over it. You have no idea if the engine jumped time, no idea if you have bent valves, no idea how much metal has been sent around the engine, and you want to stuff a new IMS bearing into a damaged IMS shaft?

As others here who are knowledgeable have stated, all of this is especially pointless if you haven't even borescoped each cylinder.

Points taken....However when last shut down this engine ran fine..... Based on that we are assuming that it has not lost timing and no interference damage has taken place. For the rest of your argument, if the engine is shot, it's shot. My friend who has a lifetime of destroying engines as a race car driver behind him, feels good about the engine, and is willing to throw a bearing at it. We'll rinse it out the best we can. As it is he's out 18 grand. There's a chance we can squeeze some more miles out of it for less than one. Plus we're having fun wrenching. I sure am learning a lot quickly.

If I ever lose my sanity and end up wanting one of these things, I'll know a lot more than I did a week ago.

Edited by Oscarvan
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This entire thing has "bad idea" written all over it. You have no idea if the engine jumped time, no idea if you have bent valves, no idea how much metal has been sent around the engine, and you want to stuff a new IMS bearing into a damaged IMS shaft?

As others here who are knowledgeable have stated, all of this is especially pointless if you haven't even borescoped each cylinder.

Points taken....However when last shut down this engine ran fine..... Based on that we are assuming that it has not lost timing and no interference damage has taken place. For the rest of your argument, if the engine is shot, it's shot. My friend who has a lifetime of destroying engines as a race car driver behind him, feels good about the engine, and is willing to throw a bearing at it. We'll rinse it out the best we can. As it is he's out 18 grand. There's a chance we can squeeze some more miles out of it for less than one. Plus we're having fun wrenching. I sure am learning a lot quickly.

If I ever lose my sanity and end up wanting one of these things, I'll know a lot more than I did a week ago.

I think your friend should come up with another $239 so you can head over to Harbor Freight and pick up a fiber optic camera to add to YOUR toolbox. This way you can post some photos for us to look at and you will earn some good will from those who are providing technical advice. After reading the description, I think I may go buy one.

...j

Description of Cen-Tech 67980

View inside cylinder heads, behind wallboard and many other hard-to-reach areas. Sharp 640 x 480 resolution camera with tempered glass lens records and plays back still images or video clips.

-Save images on internal flash memory or SD card (not included)

-USB cable lets you stream video directly to your laptop or personal computer

-Brilliant 3.5" color 320 x 240 display

-Narrow 8.5mm probe fits most spark plug holes

-38" watertight flex shaft with CMOS imager

-Bright white LED illumination

-Rechargeable lithium-ion battery

-includes: 120 volt adapter, USB cable, video-out cable, hook, mirror and magnet accessories, clip-on mirror

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Yes, have several 20% HF coupons on my desk.... from the most unusual sources.... like AARP magazine.... :eek:

Think he's getting one, then again, I think I should own one..... B)

As far as goodwill......

I am the "Expert" on some other forums, and yes it can be frustrating to watch noobs learn. Then again, it's what I'm there for. If I didn't care, I wouldn't respond.

Edited by Oscarvan
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This entire thing has "bad idea" written all over it. You have no idea if the engine jumped time, no idea if you have bent valves, no idea how much metal has been sent around the engine, and you want to stuff a new IMS bearing into a damaged IMS shaft?

As others here who are knowledgeable have stated, all of this is especially pointless if you haven't even borescoped each cylinder.

Points taken....However when last shut down this engine ran fine..... Based on that we are assuming that it has not lost timing and no interference damage has taken place. For the rest of your argument, if the engine is shot, it's shot. My friend who has a lifetime of destroying engines as a race car driver behind him, feels good about the engine, and is willing to throw a bearing at it. We'll rinse it out the best we can. As it is he's out 18 grand. There's a chance we can squeeze some more miles out of it for less than one. Plus we're having fun wrenching. I sure am learning a lot quickly.

If I ever lose my sanity and end up wanting one of these things, I'll know a lot more than I did a week ago.

You'll need the smaller head one to fit into the spark plug hole -- which I'm not sure HF has.

I don't remember the exact size

mike

I think your friend should come up with another $239 so you can head over to Harbor Freight and pick up a fiber optic camera to add to YOUR toolbox. This way you can post some photos for us to look at and you will earn some good will from those who are providing technical advice. After reading the description, I think I may go buy one.

...j

Description of Cen-Tech 67980

View inside cylinder heads, behind wallboard and many other hard-to-reach areas. Sharp 640 x 480 resolution camera with tempered glass lens records and plays back still images or video clips.

-Save images on internal flash memory or SD card (not included)

-USB cable lets you stream video directly to your laptop or personal computer

-Brilliant 3.5" color 320 x 240 display

-Narrow 8.5mm probe fits most spark plug holes

-38" watertight flex shaft with CMOS imager

-Bright white LED illumination

-Rechargeable lithium-ion battery

-includes: 120 volt adapter, USB cable, video-out cable, hook, mirror and magnet accessories, clip-on mirror

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  • 2 weeks later...

Log this failure with NHTSA

Recalls are triggered by complaints to the NHTSA. NHTSA complaints and investigations can be researched at their website: http://www.safercar.gov/Vehicle+Owners . Complaints can easily be filed there. Between MY 2000 and 2010 there were only 6 IMS failures reported with std or S Boxsters: 1 in 02, 4 in 03, 1 in 04 - not enough to trigger an investigation, much less a recall.

See this thread

http://forums.rennlist.com/rennforums/996-forum/645275-possible-leverage-for-failed-ims-engine-replacement.html

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