Cyl 1-3 Timing Out on 3 chain engine after IMS replacement

[B6T]

I just completed an IMS bearing replacement today on my '03 Boxster S. I followed the Pelican Parts DIY using the set-screws to hold the IMS in place. No cam lock tools, as I didn't think they were required using the set screws. I pulled the cam caps and marked the position of the cams on all four, as well as the crank prior to removing the tensioners and IMS bearing flange.

When I removed the cylinder head chain tensioner, I heard a pop and the tensioner sprung out with some force behind it. I didn't think much of it at the time since this was the first time I've done this job. I pulled the bearing flange, replaced the bearing, then reassembled the flange and torqued everything.

I reinstalled the tensioners and rotated the engine 720deg and then checked my markings on the cams. Both passenger side cams look like they are both out a tooth on the chain sprocket.

That pop I left was definitely the timing chain jumping a tooth on the intermediate shaft as a result of the chain being loaded up by the cams. I realized at this point how valuable the cam lock tools are and am kicking myself for not taking the time to get the tools.

So I've been searching for info on how I can correct this. I am familiar with the chain configuration of the 5-chain engine, and how you could correct this issue by re-indexing the cam drive plate behind the oil scavenge pump. But I don't think that will work on my 3-chain engine, or at best, would only re-time the exhaust cam.

My thinking is that I have to remove the chain tensioner, pull the valve cover, and try to get the cams back on the correct sprocket location, either by removing the cams, or by trying to get the chain to jump a single link.

I'm afraid I'll have to pull the engine though. That would suck.

Any information on how to correct this is appreciated.

Before:


After:

[jdraupp]

The pelican set screw directions are not recommended. If you read any of the stuff by Jake Raby, locking cams is required, and I'm sure it's your problem. Hopefully him or JFP or byprodriver can weigh in on a fix.

[Gelbster]

I thought we had berated Wayne enough about these incorrect directions? Apparently not.
Yours is a huge penalty to pay just because you bought from Pelican instead of LN. If you read the LN Instructions they are very dictatorial and in excruciating detail with many grumpy imperatives - for a reason.
Removing the M96 engine to fix their mistake - I feel your pain. I hope Pelican does too.BTW I really like Pelican and buy their stuff- they are great but this issue is their one big failure imho.
Search for something like this:
http://lnengineering.com/files/IMSR-Instruction-Warranty.pdf
IMS retrofit on a 3-Chain car - Rennlist Discussion Forums
Here is a link to a useful thread mentioned below:
http://rennlist.com/forums/996-forum/792894-996-cam-timing-after-ims-install-question.html
Good luck !

[B6T]

^Yup. I would have left the engine at TDC and perhaps reduced the likelihood that this would have happened, but you have to index the crank to put the intermediate shaft in a position where it can be supported by all three 'dowels'.

It would be nice to be able to drop nearly $1,200 USD on both the tools and the ceramic bearing from LN Engineering, but before taxes and duties, that's over $1,500CAD. Tough to justify when the alternative was the $150 Pelican kit, which at the time seemed to be able to be installed without the special tools.

There's nothing online about timing the 3-chain engines, from what I can tell. I'll attempt to pull the valve cover today and see what I can do from that point.

[johnsjmc]

You will need a special tool kit to hold the cams with the valve cover removed The top of the cover supports the cams, without it in place the cams will move. I would look online for the shop manual for a 987 or late 986 (to find 3 chain instructions ),( and read them ) before blindly removing a cover. (I have seen the instructions somewhere )

[johnsjmc]

manuals were available at Manuals_Original but no longer seem to work.

[Sassmatt72]

you can make the cam locking tool out of flat steel plate or bar.

good luck.

[johnsjmc]

You could have locked the crank at tdc with a 5/16 drill bit and made cam locks BUT too late now.
Now you need cam timing setting tools available from ebay
search " b9612-kplus" about $250 plus shipping and hst.

[B6T]

As I mentioned, I followed the Pelican Parts tutorial which specifically says to rotate the trank until you can see the IMS gear behind the M8 bolt holes for the bearing flange. This is required to provide support for the threaded pins you need to install to maintain the position of the IMS during bearing exchange.

I now realize what a total piece of poop that tutorial is.

Originally Posted by johnsjmc

You will need a special tool kit to hold the cams with the valve cover removed The top of the cover supports the cams, without it in place the cams will move. I would look online for the shop manual for a 987 or late 986 (to find 3 chain instructions ),( and read them ) before blindly removing a cover. (I have seen the instructions somewhere )

From what I can tell the 3-chain engine has a secondary bearing cap on each camshaft under the valve cover that prevents the cams from popping out when you remove the valve cover.

In the procedure for removing the valve covers, the Porsche service literature doesn't mention a cam hold-down tool for the 2003+ engine, like it does for the earlier 5-chain engines.

[johnsjmc]

If you have the service procedure for a 3 chain from Porsche read it carefully.(be careful of generic instructions like the Pelican ones. I am a licensed tech in Ont but have not actually been deep inside a m96 . I have done the IMS update to my own car though.
It,s common knowledge the Pelican IMS instructions are flawed.
The tools I referenced are also available from Kommentools.com along with some others specifically for Porsche cam timing on both m96 and m97 986,987.

[Qmulus]

Originally Posted by johnsjmc

You could have locked the crank at tdc with a 5/16 drill bit and made cam locks BUT too late now.
Now you need cam timing setting tools available from ebay
search " b9612-kplus" about $250 plus shipping and hst.

I believe that kit is for five chain engines. For the three chain, you need something like this or equivalent.

[johnsjmc]

I found a rennlist post you need to read but don,t know how to link to it
look up "996 cam timing after IMS install question " by Jim-c 12/29/13
Same issue Jake Raby got involved later in the thread and they fixed it in the car without pulling the cover.

[jsceash]

It might be possible to fix with out pulling the engine. The problem will be you need 3 special tools. It can't be done with out them. The procedure can't be found in the in the 99-04 manual, 101 project, or the Bentley manual. PM me with a email address, I can email the chapter PDF from the 2005- 2008 shop guide.

You need to read the manual very carefully and don't cut any corners. You may have to remove the cross member behind the motor bottom covers and header to have enough room.

You can probably find the tools on Ebay

Porsche 997 Engine Timing Tool Set Crankshaft Locking Tool Kit | eBay

You also need a torque wrench and a angle guide either hand made or also purchased on Ebay.

[Luv2Box]

Six years ago, when I had my IMS changed to the LN, I made a video of the procedure with my mechanics permission. Because UTube, at that time, had a restriction on the length of a video, I edited out the procedure for locking the timing and concentrated on the removal and install. I posted the video on Pelican Parts forum as a reference video with an explanation about why that part of the procedure was missing and took so much grief from members, and Wayne, about why it wasn't in the video I eventually removed it. So yes, if Wayne left it out of his procedure, after all of that, he deserves what he gets.:ah:

Originally Posted by Gelbster

I thought we had berated Wayne enough about these incorrect directions? Apparently not.
Yours is a huge penalty to pay just because you bought from Pelican instead of LN. If you read the LN Instructions they are very dictatorial and in excruciating detail with many grumpy imperatives - for a reason.
Removing the M96 engine to fix their mistake - I feel your pain. I hope Pelican does too.BTW I really like Pelican and buy their stuff- they are great but this issue is their one big failure imho.
Search for something like this:
http://lnengineering.com/files/IMSR-Instruction-Warranty.pdf
IMS retrofit on a 3-Chain car - Rennlist Discussion Forums
Good luck !

[JFP in PA]

Originally Posted by B6T

I just completed an IMS bearing replacement today on my '03 Boxster S. I followed the Pelican Parts DIY using the set-screws to hold the IMS in place. No cam lock tools, as I didn't think they were required using the set screws. I pulled the cam caps and marked the position of the cams on all four, as well as the crank prior to removing the tensioners and IMS bearing flange.

When I removed the cylinder head chain tensioner, I heard a pop and the tensioner sprung out with some force behind it. I didn't think much of it at the time since this was the first time I've done this job. I pulled the bearing flange, replaced the bearing, then reassembled the flange and torqued everything.

I reinstalled the tensioners and rotated the engine 720deg and then checked my markings on the cams. Both passenger side cams look like they are both out a tooth on the chain sprocket.

That pop I left was definitely the timing chain jumping a tooth on the intermediate shaft as a result of the chain being loaded up by the cams. I realized at this point how valuable the cam lock tools are and am kicking myself for not taking the time to get the tools.

So I've been searching for info on how I can correct this. I am familiar with the chain configuration of the 5-chain engine, and how you could correct this issue by re-indexing the cam drive plate behind the oil scavenge pump. But I don't think that will work on my 3-chain engine, or at best, would only re-time the exhaust cam.

My thinking is that I have to remove the chain tensioner, pull the valve cover, and try to get the cams back on the correct sprocket location, either by removing the cams, or by trying to get the chain to jump a single link.

I'm afraid I'll have to pull the engine though. That would suck.

Any information on how to correct this is appreciated.

Before:


After:

At times like this, I really wish the so called set screw procedure would simply disappear from collective memory.

You have had at least one cam jump time, possibly more than one. The fix is not an easy one; probably the optimum route would be to not rotate the engine any further, obtain cam holding tools, remove the cam covers, then the cams themselves, and rotate the engine to TDC on #1 cylinder. At this point, you need to start the "cam allocation" procedure, which runs some 14 pages in the service manual, so I will not try to summarize it here.

If the car was in my shop, I would drop the engine and do this on a stand, as it is both easier and less time consuming than trying to do it in the car. Once the cams are back where they belong, I would also do a leak down with the engine still on the stand, just to be sure everything is alright. You can also finish the IMS retrofit on the stand as well, but I would strongly recommend against using the non LN bearing.

Good luck, you are about to go down a very bumpy road.

[johnsjmc]

Originally Posted by johnsjmc

I found a rennlist post you need to read but don,t know how to link to it
look up "996 cam timing after IMS install question " by Jim-c 12/29/13
Same issue Jake Raby got involved later in the thread and they fixed it in the car without pulling the cover.

You really should look at this rennlist thread. The op fixed exactly the same mistake in the car with a homemade special tool and removal of the scavenge pump to allow turning the cam in the car "Jim-c" 12 /29/13

[B6T]

The threads I reviewed stating that the engine had to be pulled were for the 996 and not the 986.

I was able to drop the back of the engine down a few inches and then was able to remove the passenger side valve cover. I removed the exhaust cam drive sprocket, then removed the two intake cam upper bearings and pulled the cam out just enough so I can re-index the IC sprocket onto the correct tooth. I reinstalled the exhaust cam sprocket, also re-indexed to the correct tooth, then tightened up the tensioner, advanced the engine to TDC, and then set the exhaust cam timing.

I didn't touch the intake cam timing because I wasn't sure if it was a TTY bolt (I think it is) and I wasn't sure if that cam has the ability to bring itself back into time based on how that adjuster works, i.e. what is the resting position of the adjuster, and how many degrees movement does it have. I consulted with my brother who is a factory trained BMW tech and he said that most vane-cell adjusters are the same in terms of operation, and that if he were me he would wait and see what code the engine throws, if any. So if I see a deviation code for the intake cam, I won't be surprised.

I did a compression check and all cylinders are even, and the engine fired right up.

Now I have to get the two broken exhaust bolts out of the head and then I can get the car 100% re-assembled.

Thanks for all the help guys.

[Gelbster]

I hope someone at Pelican is reading this and understanding the needless grief their bad IMSB Instructions are STILL causing .For the number of times we have discussed this with them - even with Wayne in writing on the Forum - it is very shameful. And this from an otherwise fine company and Porsche Forum sponsor.

[B6T]

After drilling out the two broken exhaust manifold bolts (grrr...), I was able to re-assemble the car and get it back on the road. I've driven approximately 200km so far. The CEL illuminated at about the 10km mark. I read the code out with a generic OBD2 reader and got a P0012 code, which is:
"P0012 - "A" Camshaft Position - Timing Over-Retarded (Bank 1)"

I'm assuming that this is the intake cam, but would appreciate if someone could confirm. I understand the exhaust cam doesn't have a position sensor so I'm not sure how the DME could pick this error up anyway.

As noted above, I didn't touch the cam timing on the intake cam because it would have required loosening the TTY bolt and I didn't have a replacement. Looking back, I think what might have happened is that the cams skipped two teeth, instead of only one as I had originally thought. This would explain why I had to set the cam timing on the exhaust cam, when I really shouldn't have had to considering I was putting the cam "back to where it was". Then again, if I indexed the cam two teeth, it wouldn't necessarily have been in alignment either. This was a few weeks ago now, so my recollection is a bit hazy (also a side effect of working 60 hour weeks...).

So I've been searching about how to set the intake cam timing on the three chain engine, including reviewing the factory camshaft allocation procedure, and there is a gap in my understanding.

I understand that three tools are required for this job, the TDC pin, the typical camshaft holder which does in the green-plug end of the head, and the stay bar that holds the body of the intake cam while tightening/loosening the TTY bolt that holds the cam adjuster into place.

The question I have is when you loosen the TTY bolt out of the intake cam, 1. can you remove it entirely without the cam coming off, and 2. can you then index the cam adjuster on the end of the camshaft while holding the cam in place with the cam holder tool?

The second question relates more to the geometry of what restrains the cam adjuster on the end of the camshaft, i.e. is it a simple clearance bore, is it a taper, or is it some sort of shape and the position is fixed?

Basically I'm trying to figure out the specific steps I'm going to follow to set the cam timing with respect to how I loosen each cam, when I set in the alignment tool, and when I set the TDC pin, given that I can't turn the engine backwards.

Thanks for all the help guys/gals.

[jsceash]

This is a complicated procedure in the manual it has a picture or more on every page. It is
21 pages long. I strongly suggest you find a copy of the 2005 -2008 service manual. Chapter "Engine cylinder heads, valve drive". No one is going to want to be responsible to enter the procedures like this in a post have a person on the other side interpret or perform those instruction wrong and destroy their engine.

Digital and CD copies are available on Ebay for a reasonable fee. Mine was $15 US.