987.1 Engine Numbers and IMS Sizes

[pfowler1]

Hi,
I am trying to find out which IMS bearing is in my 2005 Boxster S 3.2 and have read on Pistonheads that the smaller single row bearing was used in engines up to engine No. 62504095 and the larger bearing after then. My engine number is roughly 3000 beyond this (62507803) and am hoping someone can confirm the above is correct which means I have the larger bearing and don't need to worry so much about failure.

Also I have read that some engine numbers start with 61, supposedly signifying it is a "series 1" engine and those starting 62 are "series 2". Can anyone confirm this and if so, what are the differences?

Thanks in anticipation.
Paul

 

[Tracy_Wilkins]

Hi Paul
If you contact our technical advisor he may be able to help.
steve@jazweb.co.uk

Tracy

 

[Geoff_Fields]

This was the info I saved from another forum regarding 911 engines as always being asked this question.
Engine numbers up to M96/05 69507475 has the smaller IMS bearing and engine numbers from M96/05 69507476 has the larger revised bearing.
Engine numbers up to M97/01 68509790 has the older IMS bearing and numbers from M97/01 68509791 has the larger revised bearing.
The later bearing can't be changed without full engine tear-down.

 

[stevehorobin]

Sorry, bit of a newbie question.
How do I know my engine number?
I have a Boxster S 2001 Manual.
Usual IMS worries.
Steve

 

[Motorhead]

This link might help Steve:

http://forums.pelicanparts.com/boxster-cayman-forum/600404-where-engine-serial-number-located.html

Jeff

 

[pfowler1]

Steve, you will find it on your V5 registration document.

 

[stevehorobin]

The V5 says Engine Number 67201276.
Don't undersatand what the M96/05 or M97/01 mean, but I assume I have an early engine here.
Need to get the IMS looked at then I assume?
Steve

 

[Chappelle]

The V5 says Engine Number 67201276.
Don't undersatand what the M96/05 or M97/01 mean, but I assume I have an early engine here.
Need to get the IMS looked at then I assume?
Steve

911 engines I believe, 3.6 then 3.8 and irrelevant to you unless I'm corrected

 

[pfowler1]

Steve, if your car was built between mid 2000 and mid 2005 the it almost certainly has the smaller IMS bearing that is more prone to failure. I wouldn't bother checking, just go ahead and replace it if you are going to the trouble of removing the gearbox.
I think your engine will be an M96 which was used until 2006 then it was changed to M97.

 

[stevehorobin]

Thanks everyone.
Yes, my Boxster S 986 is 2001 build so an early one.

Problem is people keep saying if the cluctch starts to feel heavy, time to change the clutch, and do the IMS bearing as well at the same time.
Being a new Porsche owner, I don't know what is a light or heavy clutch.
I've also spotted oil damp near to the rear of the engine around the gearbox join. I guess this is a gasket change.
I sense a little Spring expense coming up.
Steve

 

[pfowler1]

Steve, I wager you wish you hadn’t asked as your repair bill is mounting up. Since you have some oil evident at the engine gearbox joint, it sounds like your RMS (I think they call it) gasket is leaking and you’ll probably want to fix that. To do that you need to take the gearbox out and it would be sensible to do the IMS and the clutch at the same time.
At least if you do all this you can then rest easy and enjoy driving your car.

Paul

 

[Charles Navarro]

We get emails almost daily with owners of 2005 model year Boxster and 911 models. With a 2005, depending on build date, it is possible that you do indeed have a serviceable single row IMS bearing. I wouldn't let that stop from changing the IMS bearing out. Just depending what you find may change the route you take.

There is a small chance that you have the non-serviceable bearing, which isn't a big deal. The incidence of failure with a 2006-2008 M96 or M97 Engine as found in the Boxster, Cayman, and 911 that have the larger (but non-serviceable) IMS is highly unlikely. We would estimate about a 1% failure rate.

If you have the non-serviceable bearing, the IMS can be changed with complete engine disassembly. Although there is a company that sells a tool and kit to bore the block, allowing you to change the bearing, you should never under any circumstances do this. The debris generated by this invasive procedure will compromise the engine.

When you have your clutch replaced, it's best to have the grease seal removed off the original bearing to allow engine oil to better lubricate it. At that time, you can reseal the IMS flange and have the rear main seal replaced as well. There is a black plastic seal on the front of the bearing - you would use a dental pick or something similar to pop the seal out of it's groove. Just be sure not to loose it in the engine when you do remove it. We don't have a how-to for this, but I found a short video on YouTube that shows seal removal on a ball bearing:

https://www.youtube.com/watch?v=gCXMICrjKd4

The larger bearing found in MY06-08 engines has the same load capacity as the early dual row, which have proven to be the most reliable of the factory bearings. I wouldn't worry too much about it after you pull the grease seal. There is no need for a direct oil feed for the factory ims bearing as the bearing will be submerged in engine oil once you have the grease seal removed.

I would additionally recommend changing your oil every 6 months or 5,000 miles and use a quality 5w40 (Millers, Driven). You may consider a magnetic drain plug to further help in identifying early signs of debris being generated by the IMS bearing. I would also advise dropping the oil pan for inspection from time to time as well. We have more technical information on our website on this topic.

 

[pfowler1]

Hi Charles,
Thank you for your very informative response. The first thing I’m trying to determine is which bearing I actually have before thinking about a course of action.
my car was built in June 2005 with the engine number 62507803. Some articles suggest the smaller replaceable bearing was used up to engine number 62504095 which if true would suggest that I have the larger one. Others say it is not possible to be conclusive without actually exposing the bearing itself and physically checking it. Is that a true fact? What is your opinion on this matter as you clearly have a lot of experience in this area.
many thanks for your advice.
Paul.

 

[Charles Navarro]

Hi Paul,

I have seen the same information you have found stating the smaller bearing was used up to #62504095, but we have had customers report that they have found discrepancies leading me to recommend that regardless of what type of bearing the engine might have, it's a very good idea to still go in there. If you do have the larger bearing, it's best to get the grease seal off the bearing as soon as possible to extend the life of the bearing.

Charles

 

[pfowler1]

Thanks again Charles, I agree that is the only way to be sure.

 

[richardjjs1]

If its a 987 depends on reg year
After 2006 it had the IMS built into the engine Needs an engine out and complete engine rebuild
987 really do not suffer the IMS problem that 986 did and even then its only a very small number
987.2 got rid of it all together

There is some confusion as to when they changed the way the IMS was mounted But it is worth looking at when you change the clutch
Otherwise I would not worry
Other thing to be slightly concerned about is Bore Score if its an S