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...
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