Luzin Posted April 24 Report Share Posted April 24 Hello all, I bought another 3 chain 04 3.2 S motor to replace my blown one in my 986, the motor was taken apart prior to me receiving it for unknown reasons but they deemed it fine and replaced the head gaskets and throw a LN IMS in and leak down tested it and sold it to me. Recently I got the car running after fixing small issues and it had a P0011 but runs pretty good, my foxwell scanner could not read sensor values so I got a durametric in a few days ago and looked at the cam deviation, bank 2 is close to -1 and bank 1 is -11, the deviation is mainly unaffected by engine load and only moves a very small amount maybe a tenth here and there through the whole rev range. Actual values seemed to be close to 0 and would move up close to a whole number during load (found on a 996 turbo forum that if there is a large devation the variocam+ system will be in a kind of limp mode and not affect timing (others reported around 29 above 2k rpm with load), I do have quite a few questions If there is anything to look at besides this just being cam timing mechanically set wrong and/or slipped a tooth after they had set initially? Current thoughts are to start by pulling the green cam caps off on bank 1 rotate to TDC, lock it and see if the cam lock slips in, if not remove the oil scavenger for the exhaust cam sprocket and (not sure if above that is a reusable cap but ordered a spare just in case) that covers the intake cam sprocket (larger brown cap) and crack the one time use bolt with the tool, tap the cams back into alignment on the other end with the tensioner still tight and torque all the bolts then use the cam hold tool for the intake cam and get the 120 angle torque (Will pull the mid pipe on that side to get up in there), and is that one time use bolt PN: 98710525401? Any thoughts, insight or advice would be much appreciated! Currently got about 400 miles with it running in its current timing, no bad noises but possible power increase in the higher rpms (not positive as I bought the car with a blown IMS to begin with so guessing how the power should feel compared to a 01 2.7 I've driven in the past) Quote Link to comment Share on other sites More sharing options...
phazed Posted April 25 Report Share Posted April 25 That does sound like a problem. Congratulations for looking so in-depth into it . I have built several engines from scratch and by doing that you take everything into consideration and it is just a logical process. What you are suggesting especially on an engine as complex as the M96 is applaudable. I have a feeling that you won’t get much in the way of answers on this forum. It wouldn’t surprise me if you average Porsche Indy would not get into this and would probably point you in the direction of an engine builder, I may be wrong. Good luck with it and let us know how you get on. Quote Link to comment Share on other sites More sharing options...
½cwt Posted April 25 Report Share Posted April 25 Hartech at the recognised UK specialist for the M96 (and other Porsche motors). Maybe they can give some initial advice. Quote Link to comment Share on other sites More sharing options...
pacificjuha Posted April 25 Report Share Posted April 25 (edited) The cam deviation should be read when the engine is properly hot - most likely driven 30minutes or more first. Then measure the cam deviation (I usually do not stop the engine, but keep it on idle stright from driving and measure then). Cam deviation should not move with rpm change (minimal fractional changes you mention should be normal). Cam timing actual values do change under load and rpm's. Those you can see large change as the Variocam changes the cam timing - sorry, I can't remember the rpm when Variocam does it's magic. On 2001 engine (5-chains) I faintly remember that the correct rpm's could be approx 2500rpm... please somebody correct since I'm most like off on this recollection. Edited April 25 by pacificjuha Quote Link to comment Share on other sites More sharing options...
Ninesomething Posted April 25 Report Share Posted April 25 Worn timing chain tensioner pad on one side? Maybe someone had changed one side in the past. That's a big difference - -11. Quote Link to comment Share on other sites More sharing options...
edc Posted April 25 Report Share Posted April 25 The variance in cam deviation is often cited as a possible cause of IMS failure. Don't rule it out. Quote Link to comment Share on other sites More sharing options...
Luzin Posted April 25 Author Report Share Posted April 25 (edited) Appreciate the responses! 2 hours ago, edc said: The variance in cam deviation is often cited as a possible cause of IMS failure. Don't rule it out. If the deviation was bouncing around I would certainly not be running it and would think something might be up with the new IMS install 3 hours ago, Ninesomething said: Worn timing chain tensioner pad on one side? Maybe someone had changed one side in the past. That's a big difference - -11. If I look and the timing ends up being spot on, my current thoughts is they reused a bad guide maybe? At that point I most likely will pull the motor back out and will need to dig deeper if it's not mechanically set wrong 4 hours ago, pacificjuha said: he cam deviation should be read when the engine is properly hot - most likely driven 30minutes or more first. Then measure the cam deviation (I usually do not stop the engine, but keep it on idle stright from driving and measure then). Cam deviation should not move with rpm change (minimal fractional changes you mention should be normal). Cam timing actual values do change under load and rpm's. Those you can see large change as the Variocam changes the cam timing - sorry, I can't remember the rpm when Variocam does it's magic. On 2001 engine (5-chains) I faintly remember that the correct rpm's could be approx 2500rpm... please somebody correct since I'm most like off on this recollection. Good confirmation, when cold Bank 2: -1.23 and Bank 1: -12.13, drove around for a while and then plugged in at a parking lot and had a friend read out values during pulls (no more pulls or hard driving until this is solved 😁) 12 hours ago, ½cwt said: Hartech at the recognised UK specialist for the M96 (and other Porsche motors). Maybe they can give some initial advice. Might try giving a call and see if they'd be willing to share any knowledge 13 hours ago, phazed said: That does sound like a problem. Congratulations for looking so in-depth into it . I have built several engines from scratch and by doing that you take everything into consideration and it is just a logical process. What you are suggesting especially on an engine as complex as the M96 is applaudable. I have a feeling that you won’t get much in the way of answers on this forum. It wouldn’t surprise me if you average Porsche Indy would not get into this and would probably point you in the direction of an engine builder, I may be wrong. Good luck with it and let us know how you get on. Thank you! Will hopefully know more early next week when bolts and caps come in and I get to borrow some timing tools! Going to grab all the spare parts from the blown engine from storage this weekend (had torn it down 5 years ago to find the IMS ball bearings had managed to crack some of the crank gear teeth but somehow no piston and valve interference as one the chain guides broke and wedged itself just right (PO was starting the car when the motor fully let go and seized up) My thoughts for a 3 chain is a bad cam actuator or sensor would not be causing the issue I'm seeing but might be fun to swap them all out if the timing ends up being fine and before I just pull the motor back out On a fun note though, finally picking up my cayman Z top from a shipping terminal tomorrow so will be messing around with that this weekend, I see a ton of sanding in my future! Edited April 25 by Luzin Quote Link to comment Share on other sites More sharing options...
phazed Posted April 26 Report Share Posted April 26 Good luck with your mechanical. Interested, see your progress with the Cayman Z top. Quote Link to comment Share on other sites More sharing options...
Ninesomething Posted April 26 Report Share Posted April 26 14 hours ago, edc said: The variance in cam deviation is often cited as a possible cause of IMS failure. Don't rule it out. Would've though if it were IMS it would affect both sides and the readings would be all over the shop... Dunno. Quote Link to comment Share on other sites More sharing options...
Luzin Posted May 15 Author Report Share Posted May 15 Progress Update Non-related Issues When I went to drive my 986 down to the garage 2 weekends ago, it decided to quit starting, luckily a reverse roll start did the trick, long drive down with a few trips back for forgotten tools and parts (was nice to enjoy the ride before the fun begins), made it and pulled off the engine bay covers to start pulling the starter. Then found every pocket full of oil on top of the motor, which explains the awful leaking, after diagnosing which was a pain with tons of parts being sprayed with oil, with pressure testing the AOS lower hose (diagonal crank vent hose snaked across the engine) found pin holes, got the new hose fitted this past weekend and hoped maybe the P0011 is from oil pressure issues, but absolutely no change to the values. Also swapped all the sensor and actuators with no changes. Back to the Real Issue Turned the motor to TDC and popped the green caps for bank 1, checked with a mirror and the small c's were on the wrong side, so 360 degrees later, locked TDC and the cam timing tool slide in perfectly... so I did the next reasonable step and dropped the exhaust header and mid pipe for bank1 the rear suspension support and everything else in the way, and lastly the trim under the engine scoop vent fan, pulled the bolts for the oil pump but left it in (till the cylinder head cover was fully loose, then it slide out easily, no prying) popped the cover off (sad since this had zero leaks) then pulled the gear for the exhaust cam, the cam caps and pulled the cams. thinking the issue is now the VVT gear itself. The test I had saw was just checking VVT gears for if the lock pin when oil pressure leaks out is AFK, which would have a bad rattle symptom while the car is running which mine does not have. So after it passed that test fine but my real thought in general about the gear is the shims between the vanes cell inside would be the issue explained in a last minute test I run before taking the car apart and lead me to truly think the VVT gear was going to be the culprit. But I do not have an accurate way I can think of to prove this on the bench easily with air pressure possibly. So currently thinking of just going ahead with blind replacing this part while I'm in this far and haven't seen a simple "That's obviously the problem" yet. Last Minute Test Found some interesting results with unplugging a banks VVT solenoid, once one is unplugged the computer no longer calculates cam deviations for either side no matter which is unplugged. Depending on if it is the bank that is unplugged, if it is then that bank does not have a spec cam angle, and the side that is controlled and plugged in will have a spec cam angle matching whatever value the side that is unplugged currently is. Values shift quite a bit and quickly these are just random middle values displayed Example and results Bank 1 unplugged, B1 Cam angle 11.49, B1 Spec angle 0/ B2 Cam angle -0.43, Spec angle 11.49 Another test Bank 2 unplugged, B1 Cam angle (all over the place mostly in the 10's but sometimes going past all the way to -4 but can't stay anywhere) B1 Spec angle -0.49/ B2 cam angle -0.49, Spec angle 0 With this information and knowing that when the VVT solenoid is unplugged it is in a full open state, and makes me start to make conclusions on how the pressure is used to moved this and which way, (if anyway understand which ports are returned and feeding on the cam journal itself that would be awesome (with the garage I'm working on this in being an hour and half away I can't stare at it again till this coming weekend) but I believe currently pressure comes through the actuator in the horizontal feed in the cam journal bearing and must be suppose to be at a 0 cam angle here or else the test above would show a changed state on bank 2 so with knowing that and seeing the timing spot on and the sensors and actuator were swapped from to the other bank to rule out sensor reading issues (does not rule out wiring harness or ECU...) then there must be an issue with the VVT gear, but without having a proper test I will question it till I run another one but another thought while this deep verify the oil passages for clogs from sealant. Next Steps Going to blow out each oil passage with air and re-oil with a can, pull out VVT filter that I now know about... make sure it's not a smoking gun and blocked. (PLEASE let me know if my torque specs are wrong, I'm going off what I believe is a 05 Boxster workshop manual since I can't find an 03-04 manual with these kinds of specs, (I do have a few boxster books but they are missing important info about the 3 chain engine and the updates) also if someone has a link to pdf for sale or something like that let me know). Start by cracking the old VVT gear off the cam, replace it with another one I have from the OG engine, put the intake cam back in (new cam bolt loose so gear spins) place cam at TDC position (cam overlap), put on the bearing caps, seat them all then stage torque them to 7.5 ft-lbs, install the exhaust cam at TDC (cam overlap), put back cam lock, install sprocket with bolts in the center while pulling the chain slack around intake cam and down past the exhaust sprocket since the crank is at TDC and not U6, Once that all lines up release the chain and with everything loose, installed the chain tensioner that will be pre oiled (new washer if I can find that size at a store) and tighten to 59 ft-lbs, torque the exhaust cam sprocket to 10.5 ft-lbs, Then install the intake cam hold tool on the face, torque to 37 ft-lbs, remove the rear cam tool, install the valve cover without removing old sealant (to use the built in bearing caps), bolt most of it done snug, then torque the intake cam another 110 degrees, spin engine over and hope I did everything correct, if so pull valve cover and use locktite 5900 and torque to 9.5 ft lbs and torque plugs and actuator to 7.5 ft-lbs, pull tools and torque oil pump 7.5 ft-lbs, plug battery in, reset frames and try to start the car. If issue persist will check wiring outputs with a multi meter and make a harness to the sensor and actuator to rule out an odd wiring issue. Excited it's getting narrowed down as I hope I'll finally feel how this runs at full potential. Cayman Top Looks absolutely epic! No damage from shipping but with all the parts jammed in one side with my tool buckets and the car on the quick jacks, The top pieces have to be moved outside each time I make the drive down to work on it, making it a bit inconvenient at the time but been storing it on the car when I leave, and really enjoying how it's looking already. Quote Link to comment Share on other sites More sharing options...
Menoporsche Posted May 16 Report Share Posted May 16 Tagging @Mark Shead in case he wishes to contribute. Quote Link to comment Share on other sites More sharing options...
Halfordwill Posted May 19 Report Share Posted May 19 Help me DIY on you tube has just re built a 3 chain engine he shows how to time it and torque settings. Good luck! Quote Link to comment Share on other sites More sharing options...
Luzin Posted May 22 Author Report Share Posted May 22 On 5/19/2024 at 2:38 AM, Halfordwill said: Help me DIY on you tube has just re built a 3 chain engine he shows how to time it and torque settings. Good luck! Hadn't seen these videos yet, just gave the assembly and timing one a watch through, reassured what I had done this past weekend. Swapped my Cam phaser gear and blew out oil passages (also swapped the actuator check valve oil strainer), then reassembled everything pretty much the same with tons of oil and assembly lube. However I ran into an issue where after I did the 110 degree torque on the intake cam, the timing tool fit perfectly, but after spinning the motor the exhaust cam lined up but the intake was a hair in the slow direction (had a thin cheap amazon timing tool that still fit) but the tool I had used to lock it originally no longer fit unless I moved the crank a hair past TDC, decided I could re-time with the cover on and wanted to see what value that gave since the bolt was already spent so proceeded. Resealed the oil pan on Saturday after I finished the valve cover (both have no signs of leaks so far!) My 986 started on Sunday after some drying time, got the same code, cool, read the actual cam angle for bank 1 and its now near 21 or -21 cam deviation once the computer triggers the code. So this leads me to believe if this number is just degrees out from the crank doubled I could see that hair rotation maybe measuring up to roughly 10 at the cam? So going to take apart everything in the way again but just to crack and re-time the intake cam, going to break it loose, then use the hold tool to rotate and release pressure on the cam, rotate the cam back to TDC with the timing tool and slightly advance it so the timing tool binds when it's pointed that way but can still slide in and re-do the torque then degree torque and see what happens. Quote Link to comment Share on other sites More sharing options...
Halfordwill Posted May 22 Report Share Posted May 22 That’s very annoying I feel your pain. Have you replaced the chain pads and were they worn? keep us updated. Quote Link to comment Share on other sites More sharing options...
Luzin Posted Tuesday at 02:04 AM Author Report Share Posted Tuesday at 02:04 AM On 5/22/2024 at 2:34 AM, Halfordwill said: That’s very annoying I feel your pain. Have you replaced the chain pads and were they worn? keep us updated. Guide rails looked fine, the one that goes between the bearing caps had a crack through the pad but it was held in place due to the rivet (swapped this part out). This past weekend I retimed the engine but purposely going a tad bit too far in the advanced direction to at least see a negative value as the actual cam angle but it went from the 21 angle to an 11 not an advanced time... so now its even more advanced physically but the computer does not show that which points towards this VVT gear reacting to something differently than the other, so many this is oil pressure related. Went through the wiring and got the same results on both sides sensors (10.8V middle terminals and 5.04V on the non ground side terminal) and solenoids (9.2V when car is on) Not quite sure where to go from here, very puzzling problem, I hadn't known about the spun camshaft issue in the 997 tt's they had a pressed in fitting on their camshafts that if not pinned can rotate and block oil flow in the camshaft vanes to the gear causing the p0011 and p0021 but are the 986.2 camshaft built similarly or those were just a multipiece for a certain reason for tt? wishing I had checked for flow path in the camshaft when I was checking the snap rings but was being quick to not get debris on the bearing surface (also unknown if they are multipiece and this is possible) Put everything back together and started driving it again as I think of what to try next, if I can't resolve the issue, I'm curious if a full on parts cannon approach would work new heads, cams, wiring loom, and ECU but all from a 3.4 m97? Then a custom tune since it would be my 3.2 crank. Quote Link to comment Share on other sites More sharing options...
map Posted Tuesday at 05:10 AM Report Share Posted Tuesday at 05:10 AM @Luzin - admire your tenacity and it seems you’re being very thorough. A few things spring to mind: Are the timing chains stretched? I don’t know how to measure this but would expect to the chain links to be “loose” around any gear teeth. Be careful mixing engine components between M97 and M96 - from personal experience I know that M97 intake manifolds do not fit M96 heads because the bolt patterns are different. There will be a myriad of other detail differences. 996/997 TT “Mezger” engines are very different designs to M96/M97 so be wary of transferring Mezger engine problem thinking to M96/M97 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.