Upgraded Bearing - what does it mean

[Bbooxxsstteerr]

The local independent Porsche specialist has finished doing the bits I wanted from the post purchase inspection on my 48k miles 2004 S and, the clutch, RMS and IMS which were not mentioned on the inspection, but I just wanted them done. Only when it got to the IMS they said:

remove transmission to renew ims bearing to upgraded type found engine already has larger type IMS bearing fitted, this would indicate the engine has been changed during the vehicles lifetime to a newer style with the factory upgraded bearing - renewed rear main crank seal whilst transmission removed.

Now I don’t really care if the engine has been replaced - is that what they are saying? I wanted a fit manual gearbox, proper handbrake, hydraulic power steering sports car of the sort I coveted when I was in my 20s that someone else can (and exists) to fix so I have a proper car drive to when I’m 85 (30 years away) if I make it that far and, this is it. I will get a an electric car but then I also buy fridges and TVs.

What I’m surprised about is the suggestion the IMS is replaced at all. I do buy into the idea the IMS issue is overblown.

The history of this car - owner 1 had it for a few years from new and seems to have done regular-ish mileage and seems to have gone to owner 2 approx 3000 miles pa for a long time and, owner 3 approx 500 miles pa but that was not long before lockdown.

Did early IMS failing Boxsters get a whole new motor under warranty or an enlarged IMS? There is nothing in the service history. It is a very late 986. 

[Menoporsche]

IMS failures needed a new engine, not just a new bearing. The bearing failure on a running engine goes from fine to total wreck in 5-10 seconds AIUI, it sets off a reaction of parts smashing into each other.

I believe there is a letter in the engine number that indicates it is a replacement engine?  What is the engine number, do you know?

We have engine numbers that show where the smaller bearings finished and the larger ones start, 56lbs knows where to find them.

Supposedly the old engine had replaceable bearings, and the newer 987s had the larger non-replaceable bearings, so interesting that you have a 986 with a larger one. Does indicate that they fitted it with a newer engine.  If so - case closed, go to bed.

They didn't take a photo of it while visible? That would have been reassuring.

Edited May 16 by Menoporsche

[Bbooxxsstteerr]

It’s 67407838 if anyone knows.

They may have photos - I am seeing them tomorrow and my bill for the preventative maintenance is materially lower than I thought it was going to be. 

Many thanks

Edited May 16 by Bbooxxsstteerr

[edc]

The 986 using a single row IMS bearing is known as the small bearing. The 987 got a larger size bearing. To get that in a 986 means either an engine rebuild or the original engine was lunched and a new short engine supplied. 

[Menoporsche]

I’m not sure you can simply put a larger bearing in a block made for a smaller one?

[Dubdubz]

1 hour ago, Bbooxxsstteerr said:

It’s 67407838 if anyone knows.

They may have photos - I am seeing them tomorrow and my bill for the preventative maintenance is materially lower than I thought it was going to be. 

Many thanks

https://www.renntech.org/topic/50343-engine-serial-number-decoding/

[½cwt]

1 hour ago, Bbooxxsstteerr said:

It’s 67407838 if anyone knows.

They may have photos - I am seeing them tomorrow and my bill for the preventative maintenance is materially lower than I thought it was going to be. 

Many thanks

That is a 3.2 engine (67) from 2004 (4) model year engine number 7838, so is consistent with the model and year given at the top of the thread and would indicate a late engine number in that model year too.

This is where it gets interesting as this is an M96 engine, it is the M97 has the larger bearing that needs the case to be split to change the bearing.  Even early 987s still had M96 engines before the full switch over to the M97.  I vaguely recall reading that it is possible to machine the engine to fit a different bearing but as to how, when and in what circumstances I can't recall, although it would be major work.

AFAIK, if an IMS issue was found under warranty by Porsche, it was an engine swap, not a repair.

[Nobbie]

7 hours ago, ½cwt said:

That is a 3.2 engine (67) from 2004 (4) model year engine number 7838, so is consistent with the model and year given at the top of the thread and would indicate a late engine number in that model year too.

This is where it gets interesting as this is an M96 engine, it is the M97 has the larger bearing that needs the case to be split to change the bearing.  Even early 987s still had M96 engines before the full switch over to the M97.  I vaguely recall reading that it is possible to machine the engine to fit a different bearing but as to how, when and in what circumstances I can't recall, although it would be major work.

AFAIK, if an IMS issue was found under warranty by Porsche, it was an engine swap, not a repair.

Are we certain that the engine number on the V5 corresponds to the replacement engine and not the original engine? Do Porsche ensure the V5 is updated when they swap an engine?

[½cwt]

35 minutes ago, Nobbie said:

Are we certain that the engine number on the V5 corresponds to the replacement engine and not the original engine? Do Porsche ensure the V5 is updated when they swap an engine?

Was the engine number you gave @Bbooxxsstteerr off the V5 or off the engine?  The engine number given is consistent with the description of the car, late 2004 model year.

[map]

Having been through this - M96 engine builds and IMS Bearing decisions:

The "Larger" IMS Bearing (IMSB) from Porsche fits the M96 engine - it can only be installed whilst the crank case halves are separated and does not require any machining of the case halves.  

So a larger IMSB in a 986 engine is a rebuilt or replacement engine when it comes to a 986 - as outlined in @edc's comment above.

My 986 3.7 M96 build had the larger Porsche IMSB and a new IMS installed - the only machining on that engine was to facilitate the 100mm piston bores. Nothing else was altered.

In my case the Porsche Larger IMSB was considered to be a known quantity in terms of reliability - the aftermarket options all carry a range of warranty exclusions and "service life" definitions that make me uncomfortable.

In terms of machining to fit alternative or larger bearings - I remember this:

[map]

49 minutes ago, Nobbie said:

Do Porsche ensure the V5 is updated when they swap an engine?

Once the car is registered my understanding is that "The Keeper" is responsible for this sort of update.

[edc]

54 minutes ago, map said:

Once the car is registered my understanding is that "The Keeper" is responsible for this sort of update.

That's exactly why there is a whole thing about 'matching numbers' cars. 

[greenman986s]

1 hour ago, edc said:

That's exactly why there is a whole thing about 'matching numbers' cars. 

..doesn't necessarily mean the original engine and gearbox...just that the reg docs have been updated (at least in the UK)

[Bbooxxsstteerr]

4 hours ago, ½cwt said:

Was the engine number you gave @Bbooxxsstteerr off the V5 or off the engine?  The engine number given is consistent with the description of the car, late 2004 model year.

Off the V5

[½cwt]

1 hour ago, Bbooxxsstteerr said:

Off the V5

To satisfy us geeks out here, could you read the number off the engine?

[Menoporsche]

17 hours ago, Bbooxxsstteerr said:

They may have photos - I am seeing them tomorrow

possibly more info forthcoming...

[Ninesomething]

8 hours ago, map said:

Having been through this - M96 engine builds and IMS Bearing decisions:

The "Larger" IMS Bearing (IMSB) from Porsche fits the M96 engine - it can only be installed whilst the crank case halves are separated and does not require any machining of the case halves.  

So a larger IMSB in a 986 engine is a rebuilt or replacement engine when it comes to a 986 - as outlined in @edc's comment above.

My 986 3.7 M96 build had the larger Porsche IMSB and a new IMS installed - the only machining on that engine was to facilitate the 100mm piston bores. Nothing else was altered.

In my case the Porsche Larger IMSB was considered to be a known quantity in terms of reliability - the aftermarket options all carry a range of warranty exclusions and "service life" definitions that make me uncomfortable.

In terms of machining to fit alternative or larger bearings - I remember this:

I didn't know you'd done a 3.7 conversion - or did you buy it already done? And of course was it awesome? 😎

[Menoporsche]

It’s his current car. Shifter is rather tasty also. 

[map]

10 minutes ago, Ninesomething said:

I didn't know you'd done a 3.7 conversion - or did you buy it already done? And of course was it awesome? 😎

All detailed in my Running Report.

It is still awesome.

There are further tweaks in the pipeline - think larger intake system and an “assertive” map.

That said it’s a 325bhp engine in its current config.

16 minutes ago, Menoporsche said:

It’s his current car. Shifter is rather tasty also. 

Thank you - went out yesterday for a pootle and was thinking the contact points are still spot on - seats, shifter and steering wheel. 

[Menoporsche]

Map, you drive a 325bhp 986 with rallye spots and That Shifter - how much more assertive do you want to be?

[Ninesomething]

5 minutes ago, map said:

All detailed in my Running Report.

It is still awesome.

There are further tweaks in the pipeline - think larger intake system and an “assertive” map.

That said it’s a 325bhp engine in its current config.

Thank you - went out yesterday for a pootle and was thinking the contact points are still spot on - seats, shifter and steering wheel. 

Not dissing by any means but one of the things that puts me off the hartech if ever the worst happened is that 325hp just doesn't sound like a massive increase for the cost. That said I'm sure it's all about the torque rather than chasing silly pub bragging hp numbers. And the fact that the motor is now probably indestructible.

[map]

Just now, Ninesomething said:

Not dissing by any means but one of the things that puts me off the hartech if ever the worst happened is that 325hp just doesn't sound like a massive increase for the cost. That said I'm sure it's all about the torque rather than chasing silly pub bragging hp numbers. And the fact that the motor is now probably indestructible.

I hear you re cost especially via the very well known builders.

My situation and connections made the build viable at the time.  The biggest assist was that I had snagged a spare “long engine” albeit disassembled.  Over almost a year I collected the remaining parts before assembly began.

You are right in terms of absolute BHP/£ - it’s quite a commitment which is why I do not actively advocate this route.

The torque is a significant gain. To illustrate: on an unrestricted autobahn - in the same time my 3.2 config went from 80/85 - 100’ish in 6th the 3.7 is at 115mph and then starts pulling very hard.

A lot of care went into parts selection to maximise strength.

[map]

26 minutes ago, Menoporsche said:

Map, you drive a 325bhp 986 with rallye spots and That Shifter - how much more assertive do you want to be?

I’d like the Boxster to be the sort of assertive that can readily become controlled violence.

[Bbooxxsstteerr]

4 hours ago, ½cwt said:

To satisfy us geeks out here, could you read the number off the engine?

Well I’ve just driven it through central newcastle in rush hour and it’s in rude health. It may be tomorrow before I can get the bore scope in to take a photo (I have a fancy bore scope which gets used for almost everything decent except cylinder bores) as I gather the engine number is buried on the side of the block casing. No photos. Just getting it back has been a mission as it’s been so busy at work.