Cam timing off and opposite... WEIRD! Also RMS took a walk

I have some questions about cam timing. Bank one reads -8.00 degress and bank 2 says +5.30 degrees. HOW? If the timing chain is off by one length how much timing does that account for? Next up, saw oil start to leak dead centre from the bell housing and thought the worst. Turned out to be the RMS has just about fallen out. Is there some part of a Re and Re that could cause this? Is there a danger that a tiptronic can stress the seal when the engine and transmission are removed together, separated, and then reinstalled? I am baffled by both of these occurences. Any ideas? Anyone? I'm a noob to the 996 but not to Porsche or VAG cars.

Year/model? How does the car run/sound? What type and viscosity of oil? How did you get the cam timing degrees? Durametric? Any recent internal work on the engine? The RMS should not fall out unless it was blown out by too much oil pressure. Or it was installed incorrectly to begin with. So you found out that the RMS had fallen out...that must mean that you removed the engine/transmission, separated and then reinstalled everything. Did you get everything hooked up correctly on the engine? Thinking variocam solenoids and things like that....

Ah... of course... It's a 2001 transition year C2 Cabriolet with a tiptronic. The car was super smooth and quiet on initial start up. It started developing a lopey idle after a few drives which one knowedgeable chap said looked like a vac leak to him. The timing was read on a durametric but was confirmed to be out using the PWIS system. I put fresh fluids through the car including the DRIVEN DT40 oil that some recommend. How would I get too much oil pressure? Too much oil? We stuffed a camera up inside the bellhousing and you can see the RMS has walked way out and is sitting on an angle. The engine was freshened up about 20k miles ago by a reputable Chicago area shop. Other than shipping here to replace my engine with a detonated IMS and changing from a manual car to a tiptronic there's no differences I can think of.

So here are some shots from the DME readings... Looks like I need an O@ sensor as well. And why would only cylinder #5 be retarded?

Spark plug and coils ever been replaced? Could be a bad plug and/or coil on #5. The DME will detect a misfire on a cylinder and retard the timing.

Quotes source post: 14931912

Good suggestions; maybe OP drove in the dry then hit some rain/wet roads? water gets in the coil cracks and causes misfires

Apparently there was some difference between the coils from my 2001 and the 1999 that this motor came from so we swapped the coil packs over to the original ones but i still have all the 'new' low mile ones that came with the motor. might be the same for the injectors as well. I'll have to check on that. Good suggestions. Wouldn't a retarded timing be because the AF is lean? Would this point to an injector? And what about the bank to bnk timing deviation? One minus and one positive? Seems very odd!

In my opinion (take it for what it is) you need to sort out the O2 sensor problem, and perhaps the MAF sensor first, and the problem with #5. If I remember correctly the MAF should read between 14-17 kg/h but I could be mistaken on that. You also need to check for a vacuum leak somewhere. All of these will affect engine running as the DME uses all of the sensors to set air/fuel ratios and running parameters. I would also replace #5 spark plug and coil pack. There are new and upgraded coil packs that you should consider, replace them all. It is possible that the #5 fuel injector is bad as well. I don't know about the bank to bank timing deviation. That would require really digging into the engine to check the timing on both banks. Possible that one of the chain sprockets on the end of the camshafts slipped (the bolts that hold the sprocket on the camshaft). Highly unlikely the chain drives jumped a tooth. Could be a variocam solenoid issue such as one side sticking open/closed. But at this point nothing can be ruled out. I would correct as many known problems first before tearing into the engine to check timing. From Loren so I stand corrected on the MAF readings At idle, air mass flow should be 12 - 24 kg/h. No load, 2500 RPM should be 40 - 70 kg/h.

well i need to drop the engine to install a new RMS anyway... while I'm at it....

Quotes source post: 14932532

don't need to drop the engine for RMS

It's a tiptronic, i thought that means it's just easier to drop the whole shebang.

Quotes source post: 14931825

^^There's an awful lot of information to be unpacked right there... So this is a replacement engine? Where did it come from? How many miles, history? Why was the engine "freshened up" by the previous owner, and exactly what was done? It's strange to have so much negative deviation on one bank and positive deviation on the other - have you gotten a CEL ? Were the cam chain pads done in the "freshen up"? What about the chains/tensioners? The fact that your RMS has "walked" partially off the crankshaft is fairly bizzare - either it was poorly installed (which would be the simple/best case scenario), or the crankcase is uneven/poorly machined, or your crankshaft has some crazy runout, or, or, or... Good luck with it, and keep us informed on what it turns out to be...

According to the PO of the engine it is a 1999 that was torn down not long ago (I can't recall the exact miles so suffice to say less than 25k miles). It has new chains, tensioner pads all round (this was the reason it was stripped and 'freshened up). The bores were clean, new tensioners and maybe actuators amongst other things. Apparently there has been a rash of failing seals of brands that are similar but NOT OEM. I am hoping that is the case. The engine burns no oil and there is zero smoke at start up. When it comes out we'll install the IMS Solution (Thanks to LN and the gang! What amazing work they have done through the years to figure out all that ails these M96 motors!) The engine build used new coils and plugs but I think my mechanic used my old coil packs for some reason. I'll swap those back on and clean the MAF as discussed above. We think one of the chain tensioners might be leaking as well so we'll look at those as well. I will be sure to post a follow up when we finally have things sorted out. How do you like those NYC Link units going in all over NYC?

When you had the Durametric hooked up, did you do any activations? Such as activating the variocams for each bank? Sounds like you are pulling the engine out and working out a plan. I wonder if there is any difference in the CPS (crankshaft position sensor) for manual transmission and tiptronic. When you swapped out the manual for the tiptronic, did you swap over all of the parts? Inlcuding the DME? My thinking is that the engine management map might be different manual vs tiptronic since it has to deal with the TCU (transmission control unit) and other aspects of difference between the manual and automatic, shift points, etc.

We swapped the entire engine harness across from the original motor to the donor 1999 3.4 and used the original DME. This was done mainly to accomodate the e-throttle as the 1999 had a cable throttle Good point that some sensors might be different or even positioned slightly differently. I'll look into that. The shop did acivate and hear the actuators function for the variocams.

Could you have a crank thrust bearing issue ?? If this was the case maybe the crank moved back more than usual causing the RMS to pop out, might be worth a look in the sump ? Also maybe check the crank pulley for end float play, if a thrust bearing has failed and it can on these engines you should feel lateral play on the crank pulley with the belt off?

Okay, I'm totally confused. The car as you described- It's a 2001 transition year C2 Cabriolet with a tiptronic The original 2001 engine and transmission was a manual and it died because of the IMS So you replaced it with a donor 99 3.4 and tiptronic transmission You swapped the engine harness from the 2001 C2 transition year toasted engine to the 99 3.4 engine because of the E-gas throttle, the 99 motor which was originally cable throttle But you kept the original DME for the 2001 C2 manual transmission car and are using it on a now 99 3.4 engine with E-gas and tiptronic transmission I just don't see where anything could go wrong........

just saw this thread. If it helps at all, I was the one that sold the engine to the PO. Engine was rebuilt less than 5000-7000 miles ago due to worn IMS chain guide. We had no choice but to tare down the engine to get to that bastard. In the process of the rebuild we replaced: chains, guides (all), rod bearings, machined heads with fresh valve job, inspected bores (they were perfect), new chain tensioners new gaskets for everything, new Tstat and I'm sure I'm forgetting a bunch. Most gasket, bolts and assembly parts came from Pelican Parts. We did not replace the cam actuators but did replace the guides for them. After the engine was re-assembled, we checked for cam deviation and it was within spec (cant recall exact numbers, but I believe it was less than 4* difference). I monitored short and long term fuel trims and they were all within porsche spec. Maf read 3-5g/sec and 150g/sec at 5K. Timing was dead on, no hesitation or a single misfire during my ownership. I can try to find the dyno graph to show power band, but it was healthy without any weird dips or drop of in power (made roughly 250whp). When we pulled the engine, there were no signs of any leakage from the motor either from the IMS or RMS. This is a very bizarre case, I feel really bad for TheBird here. If anyone has any questions that they think may help in the situation I will do my best to answer them.

Thanks for chiming in bud. I hold no grudge. I can't. We'll figure it out. When we post the results the info will be here for future reference because we can't be the only ones! Cheers!

Quotes source post: 14934914

^^ ^^ No disrespect to the OP, but this is what I was sort of getting at. While I concentrated on strictly mechanical issues (which as far as we can tell is what's going on) there are many potential issues with swaps such as these. I think as far as hardware goes, the sensors themselves should be the same

No worries. I am hard to offend online! :-) all information is good. Whether it is to rule things out or open other anvenues to consider it is all good. I appreciate everyone's input.

From a quick look at the parts diagram, I see differences in part numbers for the head parts. M96.01/02/04 are one set of part numbers. The M96.03 engine is different with separate part numbers. Which engine do you have? In particular I noted there are different part numbers for the entire heads M96.01/02/04 vs M96.03. And what version of the DME are you running? Where I'm headed - you had a 2001 engine and replaced it with a 1999 engine. The 99 engine was run with an earlier version of DME, where now you have a 2001 DME version running a 99 engine. Could be subtle differences throughout the engine and DME version that is causing your deviation difference. And from your Post #3, the car was running super smooth then developed a lopey idle. Mech said a vacuum leak. Have you checked for a vacuum leak? Smoke test? Wonder if we are just chasing down a vacuum leak since the engine was running fine before.

The M96/03 is the 3.6l engine.The M96/01, 02, and 04 are 3.4l engines and I believe they were produced through 2001 (and probably later due to the warranty replacement program etc.). As we all know, there is no strict cutoff dates regarding the codes. It seems Porsche uses/used parts that they have on hand at any given time to build various different engines. How they keep track of this stuff internally is beyond me, but they've clearly been able to do it for quite some time...

Yes... found a mssive vac leak. The RMS has almost fallen out. not sure if there is more. but why would a vac leak make the cam positions wander + and -? I wonder is the sensors are slightly different as suggested before... The major DME change is from a cable throttle to an e-throttle.

So your engine is a 5-chain variocam engine. Its timing is infinitely adjustable by the 4 screws holding the exhaust cam sprocket (see Figure 8 here ). Your cam deviation reading is possible even without the chain slipping a sprocket. I think someone needs to remove the cam covers and check the cam timing physically. -8 degree is at the end of the limit. Also the FRA on both banks are close to 0.9 (ideal value is 1.0), which means the DME is pulling fuel when the engine is under load. May want to check if the fuel pressure is in spec.

^^ OP said he was going to drop the engine and transmission for the RMS replacement, so a really good time to check the cam timing. Could be just needs some adjustment. Tricky business to get it right.

Quotes source post: 14937364

That's good. May also want to measure the crankcase vacuum before that. RMS seal popped out is disturbing. You would think a high vacuum in the engine case would have sucked the seal in, not pushing it out.

With the cam deviations being so far out, I wonder if the crankcase developed positive pressure at times, pushing out the RMS as a relief and ended up causing a massive vacuum leak. Either that or it was installed incorrectly, or it was a knock-off Chinese seal. Any way it goes, something somewhere is out of whack. What a mess to deal with......

Well the engine is out of the car and it turned out the timing had been set up wrong. One bank was out by a link. The rest seems OK so she should be back together by the middle of next week.

Quotes source post: 15029488

^^WoW^^ !!! I'm surprised that that wasn't evident as soon as the engine was started for the first time, and that the DME would be able to compensate for that. In any case, it's great that no collateral damage was done and hopefully your RMS will behave now.I bet you can't wait to drive it!

Damn straight! Can't wait to get behind the wheel again. It's been over a month of good top town weather already. So with the new RMS, LN Engineering IMS solution, cam bank timing set and wear pads checked/replaced if needed she should be good to go for quite some time. Next up I need to get a descent stereo in there.... Oh, and I should replace the rotors and pads soon... sigh.