Who has done an IMS change (New Oil Fed Design Idea)

[feelyx]

what diminsions do you need? the bearing is 20x47x14mm

[feelyx]

nice sketch...

[harrisracing]

My idea of simple adapted journal bearing.

I think this:
1) Adds strength to the IMS flange to support the shaft
2) Completely prevents total failure as even if the bearing wears it will at worst make noise and not shear a bolt.
3) Is a cheap and serviceable solution.

IF we can find (or have made) a bearing that will fit just inside sprocket cluster of the existing IMS shaft this will be a very simple setup to at least try out. As stated I can try my best at getting the clearances and oil feed requirements figured out.

feelyx - I am SO sorry if I am hijacking your thread. I figured this all applies and I know of NO ONE that has put in as much effort as you have.

Plug is GREEN (it keeps oil from going into IMS shaft at all. It is threaded internally so you can screw a slide hammer / puller into it and pull the bearing out if you need to service it.

RED is Bearing - simple journal bearing like any modern camshaft bearing.

YELLOW is new IMS / Case flange. Note the drilled oil feed / drain lines

ORANGE is oil flow. IN from outside (similar placement as feelyx's), OUT from center and down into case.



All comments welcome.

Dimension I need is the depth of the sprocket to the IMS shaft that it's pressed on to. We can all assume that the inside is just bearing OD + a few thousandths.

Patrick

[feelyx]

here are some pics of what the parts look like.. there are different covers as updates came out. inside the shaft is another tube pressed in as a lock.

[harrisracing]

SO I see that the tapered collar is pressed in to expand the IMS shaft to lock it to the "sprocket cluster". That should only change the "shaft plug" design. Either way a simple flat disc that could be installed with some good sealant would be all that is absolutely necessary. Would be nice to have that plug integrated into service as previously stated.

ID and depth of all IMS shafts would be nice. That would at least give me enough to do some math. That and what oil supplies you worked with and what was available through your current fittings, etc.

Does my second sketch add any light to my idea? Seems like we may have 20-25mm to work with inside that shaft afterall. AND we know that surface is concentric and machined true since it's the mount for the factory bearings.

Also why is that snap ring in there?

Patrick

[feelyx]

the snap ring was a set point. When you heat a shaft up beyond 350F it will literally fall apart.....
the sprockets are actually 2 pcs.

[feelyx]

I say build it.. the more we learn the better off we will be.
Also, I only have the double bearing shafts left the single row bearing shaft is enjoying a new life in another engine and I will have to look through the writing on the workbench to find the diminsons.

[harrisracing]

Last question for now is:

What are the ID's for the shafts (or OD's of bearings?).

Again, I think your lubricated bearing is the absolute best option out of all of the ones available. Reason is the same as yours I think the bearings are overheating at low engine speeds. If you think about it, the slower the speed, the more dynamic the cam and crankshaft loads are on the IMS shaft. At higher rpms I bet the loads from the chains all start to turn into static loads. That, coupled with lubrication not "splashing" on the bearing just seems like a recipe for failure.

My mother in law's car has 24k miles on it. I can only imagine the engine RARELY got over 4,500 rpms as she is 62 years old. I would think the cars with low mileage failures were driven very similarly.

Thanks So much,
Patrick

[feelyx]

47mm

[feelyx]

Take some pics when you disassemble the motor and let us know what you find
Enjoy
Tim

[howe00]

Patrick, Feelyx,

My guess the reason for the circlip is to locatate the IMS shaft axially.
With a plain bush as per the sketch above the shaft is not located axially hence is free to float.

[harrisracing]

I do believe the existing front journal bearing includes the thrust area as well. Makes more sense to put the set point on that end as this is the part that stabs into the oil pump and would require a set dimension.

Patrick

[feelyx]

Originally Posted by howe00

Patrick, Feelyx,

My guess the reason for the circlip is to locatate the IMS shaft axially.
With a plain bush as per the sketch above the shaft is not located axially hence is free to float.

Hi Howe00... I think the one he was refering to is the one I had in the bottom of the tube when I pressed everything back together. But your right the shaft floats to a degree.

[harrisracing]

I had a LONG conversation with some of the mechanics over at the dealership where I picked the car up this past Friday. It was depressing. He had a few shafts (even the "Big" bearing 996 or 997 shafts) laying there for "yeah I fixed that" decor.

I can't believe how bad Porsche screwed up on this deal...and I further can't believe that they aren't taking care of it for their people - but I digress.

The mechanic seems to think that it is lubrication problem as well due to the fact that even the big beefy bearings and flanges still have failures. I tend to agree with him (and you) on that to a point. But the "lack of lubrication" theory and the "is a ball bearing really the best choice for the application" theory both suggest a bad design period.

I also got to see the brand new 2013 Boxster there. WOW what a SEXXXY car!! I was impressed for sure. The best news is the mechanics response that "NO new Porsche engines have intermediate shafts any longer". Of course Porsche does want $65k for them, which I guess in comparison to the $25k recommended repair bill of the 2003 boxster that I had with 24,800 miles on it, doesn't sound like "too" bad of a deal.

[feelyx]

Patrick, if you need some help with the machining of some of your designed parts, let me know.

[Vizor]

Feelyx, I've been following this thread from the beginning, great work and thanks for sharing.

[feelyx]

Hi Vizor.... thanks for the comments.
Here is a pic of the variocam plunger a spring. Does the debris look like this spring? It sits under the plunger and could be missing now if it broke.

[feelyx]

Oh and a quick update everything is still running great...

[showbiz]

Hello Tim, Good to see the testing is going excellent! when can I buy some stocksjust picked up a 2000 C4 Cab,Girls want a new autocross Porsche looks to have a IMS brg problem dealer did a service 1000km ago ? and when I took the oil filter off and lots of metallic bits (BRG) in filter,runs fine but want to do a IMS inspection..before it starts again .and retro fit with yours or ? it has 114000Km on the clock was serviced from dealer since new. all the best and great work on the IMS fix Greg

[harrisracing]

Originally Posted by feelyx

Patrick, if you need some help with the machining of some of your designed parts, let me know.

Will do, thanks so much.

I put the car on the lift and started removing the engine last week. Out of town on vacation this weekend, but I should have it out by next weekend to at least see if it is salvageable or not.

I am going to wait until I can get solid dimensions for doing journal bearing calculations.

Patrick