If it were me, first thing I would do is slowly and carefully turn the engine clockwise to zero timing and lock it. Now you've unloaded the valve spring tension from trying to rotate the cams. Chances are good you won't lose valve timing, and you need the engine at TDC in any case. I would not remove a tensioner before rotating the engine, you want chain tension to keep from losing timing. The pickle you are in now is losing timing by rotating the engine (my engine ran at low RPM for two blocks with a failed IMSB before it was turned off and did not lose timing) or loosening the chain tension to try and center the IMSB bolt, which might allow the valve springs to rotate the cams. I have first hand knowledge that the cams can rotate in spectacular fashion due to valve spring tension (one of many mistakes I've personally made during engine re-assembly). The other thing that is going on is the IMS shaft is supported by a journal bearing at the other end, and the geometry of that bearing is none too happy with the loads currently being imparted on it. That's my 2 cents, with luck others will chime in with their respective experiences.

thanks will check the link

Thanks for your detailed help,
i did remove both tensioners at the back first,something made a click noise inside the engine,i think it is the cam moved because of the valve springs,still i am afraid to turn the crank to lock the engine at TDC,i removed the rubber covers of the valves and it looks like the timing is lost now


http://986forum.com/forums/uploads01...1421058018.jpg

I certainly understand not wanting to crash the valves into the piston by rotating to TDC with slipped timing. I saw some sage advice recommending finding a good mechanic when this happens. You might be at that point.

My Indy mechanic is from Germany where he was Porsche trained. He was the lead mechanic for Brumos Porsche in Jacksonville for 24 years and had his hand in every engine that was built and used there for all of those years.

Has he experienced an M96 engine that failed due to the oil pump hex key falling into the IMS tube?

To fully understnd the anatomy requires cutting open components for cross sectional views.

Experience helps, but it isn't a guarantee. For example, consider the years of experience the Porsche team had when they designed the IMS in the first place.

Agreed. , although according to my Porsche mechanic friend there is a lot of pressure and decisions being made by bean counters. That is one of the reasons he left corporate after 24 years.

Why not drilling a small hole along the groove of the allen drive? All metal debree can be removed. The IMS tube is full accessible, so you remove debree. Oil pump is also full accessible. The hole must not be that big.

The downside of the idea in general: you loose oil pressure for other engine components.

Regards, Markus

And you flood the IMS shaft, which also may not be such a good idea.......

How are these roller bearing installations handling thrust loads ...if there are any. Do any have this installed? I hope oil film is not being relied upon.

Personally, I would not be at all on board with putting a groove down the length of my oil pump hex drive. A centre hole may work if you are a gambling man. That section looks too small to begin with an now one has introduced notch sensitivity that is off the scale for torsion.....imho

Yes, a good idea -"The Solution" uses one. IIRC it is the only IMSB to do so.

That is because it is part of the patents for the Solution.

Bump.

Lots of interesting discussion in this thread and I thought it would be worth bumping to the top. I'm looking for a thread where either Jake, Wayne, or Charles said that the Pelican Parts IMS Bearing retrofit was supplied by LN Engineering at Wayne's request for an affordable option. (Basically it's the same as the factory single row bearing, but has an improved bolt and comes with new seals.) I think it cost about $160 when I bought one. $399 now.

Did you mean this ?
https://lnengineering.com/pel-ims-1-pelican-parts-intermediate-shaft-bearing-update-kit.html

The budget IMS (LN) bearing is now the RND bearing..Suggest you forget the Pelican bearing .The cost increase for using a much better bearing is insignificant in the overall cost of thIMS replacement job + all the wise "while you are in there" work.
https://rndengines.com/roller-bearing-ims-retrofit-kit/
My Pelican bearing fitted by P.O. worked O.K. but he failed to remove all the circulated debris from the original IMS failure. Result was the need to rebuild the entire engine.
So whatever bearing you use, the results can be compromised by lack of due diligence .This is often dismissed as excessive. For example the "Solution" fitting Instructions are 33 pages long and the pre-qualification Instructions are 11 pages.
So skill.,specific specialized tools,diligence and strict observance of Instructions is probably more important than just bearing design ?

Yes, that's the one that I had intended. The old link I had for it is re-directed here now where it shows the $399 price: https://www.pelicanparts.com/catalog/shopcart/986M/POR_986M_UPG996_pg2.htm

I wasn't recommending it, but trying to remember some history on this forum to add to a discussion on another forum.

Personally, I like two retrofit options for the single row bearing; Single Row Pro which I have installed and IMS Solution which I may install when I replace the clutch on my '04. :cheers:

When I was looking at IMS options the other day I noticed the same thing. On the LN website I still see the cheaper one, but on Pelican’s site they rebranded it Rennline and jacked up the price. They both use the exact same picture too.

I like some Rennline stuff, but others seem like a cash grab.