Another IMS bearing thread

[Jamesp]

Originally Posted by Boxe1

So i face a big problem now ,
Any other advice ?

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.

[Boxe1]

thanks will check the link

[Boxe1]

Originally Posted by Jamesp

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 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

[Jamesp]

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.

[BobRickel]

Originally Posted by Jake Raby

The part he is center punching is the only thing holding the oil pump drive key from falling into the IMS shaft during operation. I see these failures occur without the assistance of a center punch.

It helps to understand the anatomy of the patient before performing the surgical procedure.

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.

[Jake Raby]

Originally Posted by BobRickel

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.

[thom4782]

Originally Posted by BobRickel

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.

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.

[BobRickel]

Originally Posted by thom4782

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.

[Smallblock454]

Originally Posted by BobRickel

My local indy mechanic has been working on these cars for years. His fix is the EPS fix shown in this video:
He charges $1400 to do this on cars with Tiptronic, which includes all parts and includes changing out the AOS, belt, and plugs.

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

[JFP in PA]

Originally Posted by Smallblock454

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.......

[jaykay]

Originally Posted by Smallblock454

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

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

[Gelbster]

Originally Posted by bobclive

Can a blanking plate be fitted before inserting the new IMS bearing. this would stop oil getting into IMS shaft and stop air pressure into bearing from inside shaft, just a thought.

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

[JFP in PA]

Originally Posted by Gelbster

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.