Greetings 996 gurus!

'03 Carrera 2 Cab, 6 sp. 152,000 miles. Owned it since 40,000 miles

Please bear with me, for the benefit of setting the background and facts straight:

• This started with a suspected AOS issue, based on the crazy puffs of white smoke, and lingering small amount of smoke afterwards, along with very strong suction at oil filler tube cap. (Sorry it wasn't measured scientifically), and dropping oil pressure when warm. At idle, it would shut off eventually, just as it gets warm and as oil pressure dropping.
• It coincided with a leaky coolant tank and bad water pump
• Checked oil sump and found 2 small brown plastic pieces. Im thinking these are camshaft chain guide pieces. Elongated, 1 mm thin, roughly 10-11 mm long, and may be 2-3 mm wide. See pic. No visible metal shavings or powder or anything sticking to a magnet
• Found oil seeping at the bellhousing/engine parting line. Now please don't sentence me to Porsche jail just yet, but I'll understand if you do. IMS and RMS are still original. Kept waiting for the clutch to go to do it all at once, but the darn thing has been perfect for the last 110,000 miles! (Still within spec, actually!!). Found the IMS to be leaky. No oil seepage from RMS.
• 3 composite fins on water pump are broken
• Zero history (and still none) of metal flakes in oil filter or sump. Only 2 small brown plastic pieces newly discovered in sump. No metal
• Oil is certainly not contaminated with coolant
• No chain rattling noises that I could tell
• Oil dripped out of the vertical coolant line, at the exit of the oil pump console. Small amount. Nothing frosty. Just a small amount of black oil. No oil anywhere else in the coolant system. I'm thinking there will be more of it collected in the bottom of the oil pump console, on the coolant side. Vacuumed everything meticulously
• As I vacuumed all coolant lines (and engine ports, the best I could), in my failed search for the broken water pump plastic, I retrieved a rather large piece of curly aluminum (non magnetic) shaving from the large coolant hose (that was connected to the oil pump console). Basically it came from the radiator end. I'm thinking this broke off either from the oil cooler, (which could explain the small amount of oil in the coolant line), or from one of the radiators. I haven't put together a pressure testing jig to pressure test the oil cooler to confirm, yet, but it's coming. Any other thoughts? Picture attached
• Old AOS holds vacuum perfectly from one of the smaller ports, and has a tiny leak when vacuuming from the other port. New AOS holds vacuum perfectly regardless of where you pull vacuum from

Because of my back injury, and since I'm not a contortionist to start with, I decided to drop the engine/tranny to check everything and tackle the tasks at hand, that include IMS bearing replacement, RMS replacement, checking/replacing timing chain guides, replacing coolant expansion tank, replacing AOS, and chasing whatever else needs addressing

An issue came up in the process of prepping to tackle the tasks at hand:

The camshaft alignment tool is not lining up perfectly for locking the camshafts on bank 1. I could push one end of the tool sideways with my thumb and flex it enough to barely catch onto the intake camshaft groove with the help of a tap with a rubber mallet, but it just rubs me the wrong way that I have to do that. It's basically off by a hair. I weigh less than 150 lbs and was able to do that with my left hand (I'm right handed), so it's not an excessive amount of push, though still need the tap of a rubber mallet. Issue is the same when rotating the engine an additional 360 degrees, or when trying it on bank 2.

Should I loosen up the bolts on the cam sprocket to make this small adjustment before proceeding, or should I proceed to replace the IMS bearing with the current, less than perfectly fit lock on the camshafts?

This all may make a great story on how some of these events are either connected, or randomly coinciding. But in the mean time, I'd like to know if it's ok to proceed with the IMS bearing replacement, knowing the camshaft alignment tool is not as perfectly fitted as I'd like, without help. Or should I make a small adjustment by loosening the bolts on the cam sprocket(s). Of course I plan to remove (and replace with new when done) all 3 tensioners as I move on to check chain guides and everything else. Just want to make sure there's no play in the IMS shaft as I rotate the engine to do other work, therefore I'm thinking that needs to come first

Apologies for the long post and thanks in advance for any insight or suggestions you may have


Aluminum shaving in large coolant line

Brown plastic pieces in oil sump

 

U should have measured your cam deviations before u removed the engine.

At this point if u r not going to pull the cam covers and change the vairiocam pads then i would just re-time the bank after u do the ims.

imho, at this milage i think its a mistake to not change the variocam pads and cam chain.

 

The brown plastic is from the chain guides. This is on 03 so it's a 996.2 which has different guides or pads and only three chains. It's a different process than 996.2. I'm interested in doing this as well. Hopefully we can get some good info on how to do that.

I would be very hesitant to move forward as it is. Maybe run the chain around another 360 degrees and try the locking tool again? taking it apart with out locking it down seems very risky. IMO. I have never done this job, so I'm not sure.

Best,

 

Yup sorry missed the year. Ignore my comments in the variocams as they do not apply to u.

 

No worries and thanks for trying to help. You're right in needing to take Durametric cam deviation readings before engine removal. I have many excuses, none of which are good. Least of which is that I kept waiting for it to be available for an Apple/Mac device. Anyway, the info on the 3-chain engines is rare, in terms of which plastic parts are accessible or likely to be worn and replaceable with reasonable amount of disassembly, without removing heads. So the research continues.

 

Yes I've rotated an additional 360 degrees and same issue. I agree that I should ensure proper lock before attempting the IMS bearing replacement. Another reason why I ordered another locking tool, so I lock both banks simultaneously....also hoping there is a tolerance issue with the locks and hopefully second one fits better. Thanks

 

Get yourself the 996 Bentley maintenance Manual (It covers both 3.4 & 3.6l M96). I'm pretty sure you remove the chain tensioners before removing the IMS flange (It's been a few years since I did mine but I think that's what I remember - you don't want chain tension on the IMS!). Hopefully you're doing the IMS SOLUTION - in which case, you'll have great instructions/guidance to go along with the parts. Good Luck

 

Thanks! I've been researching and studying all of the solutions and yes of course, conservatively speaking, all 3 tensioners will come off before proceeding (although there is a ton of controversial instructions out there on the topic). Another controversy is requiring banks on both banks to be locked, yet they provide only one locking tool! This is especially critical for the 3-chain engine. Yet it's treated like a taboo by all IMS providers. There is a gap of information/instructions in each and every single instruction that I've viewed and read. I may be be approaching this too meticulously, but I'd rather be safe and SLOW than sorry.

As for the Bentley Manual, yes it looks like it will have to be my only resort, though I expect it to be similar to the factory one, requiring unnecessary extra steps of disassembly, without the "tricks of the trades" so to speak, for example identifying plastic parts that are accessible to replace without total head disassembly. Nevertheless, in the process of sourcing the Bentley Manual as we speak.
Thanks again

 

I'm following this thread as well. I don't think you are being overly cautious as, from what we've read on the internet, these engines can be tricky. I'm also not new to wrenching and want this engine to last as long as I can. I've got a 94 Ford Ranger that I paid $1000 for 17 years ago. It runs great! While the 911 is certainly a more interesting engine I'd like to see what I can do with it. I really enjoy learning about how Porsche approached the project and why things are designed the way they are.

I've got a Bentley manual and there is a not a lot of detail for just replacing the chain guides.

Sounds like you are dropping the engine. Good luck and be encouraged!

 

The black piece is from one the chain ramp and the dark brown is from the variocam pads. All but the (intermediate shaft chain pads) can be replaced without pulling the heads. To get the intermediate shaft pads out, the case needs to be split.

 

As already mentioned, the OP has a 3-chain engine, which of course doesn't have the camshaft actuator.

 

would you know of a source for the 3 chain? You seem pretty knowledgeable about these cars.

Do you shoot video too? good to see you posting again.

All the best,

 

I have a spare M96.03 that I'm planning on rebuilding. Thankfully, I have all the parts (including ancillaries). The block suffered bore scoring and so I'm going to have LN Engineering bore it out to 3.8 with nikasil. That's my plan.

Yes, I work with the Knowledge Gruppe to produce content for Jake Raby's Rennvision channel as well as special projects.

Thank you for the nice comment! Glad to be back.

 

Just an FYI, the black piece is actually silver - sorry for the poor lighting - it's shiny aluminum that dulled out. And it was retrieved from a coolant line, not sump
The brown pieces were in the sump

 

Didn't catch that. Thanks for pointing it out.