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I realize this may not seem so, but this supports what I wrote above as to how one can easily destroy the casing without hurting the filter media when a oil filter bypass valve is present, which to my knowledge the LS engines have in their block. It does not mean the opposite can't be true when a oil filter bypass valve is not present. Are you talking about the oil filter bypass valve or the oil pump pressure regulating valve (PRV, sometimes called bypass too)? I am aware that many cars (including the newer Porsches) have an ECU controlled variable volume oil pump which disconnects the long standing history of oil pump output being tied directly to engine RPM. In these cars, you can rev it all you want hot or cold but the ECU is in control of the resulting oil flow instead of a passive PRV. If this level of control can adequately protect the filter media and eliminate the oil filter bypass valve, then cool! One less cost engineering rant I have to sit through everyday. If you know of a traditional oil pump with a passive PRV that does not have an oil filter bypass valve I would like to look at it and see what accomodations they made, seriously. Agreed, no arguement about HTHS, that's why I was happy that what seems to be the optimum set up to alleviate the noise (which may or may not be a lifter, I still don't know for sure what it is... for a while there I was certain it was timing chain slap) was an oil that is Porsche A40 and therefore meets their HTHS requirements. And FWIW, its also the oil that Charles and/or Jake were recommending at one point I think, maybe they still do if you're not buying their oil. To be honest I think that is talking around the subject without coming clean on an error. The kinematic viscosity is what's published on all the oil spec sheets per the ASTM D445 you reference. So read it, it clearly shows the kin viscosity is higher (= "thicker" = more resitant to flow = produces more oil pressure at a given oil temp and flowrate) at the cold 40C test temp than it does at the hot 100C test temp. Look at the M1 0W-40 PDS sheet. The kin vis drops over 5.5 times for only a 60C temp rise. Mobil 1 0W-40 Viscosity, cSt (ASTM D445) 75 cSt @ 40C 13.5 cSt @ 100C All that aside, for anyone interested the HTHS is more analogous to the real operational viscosity in the engine than the kinematic viscosity, because the HTHS test includes pressure on the fluid sample which effects the apparent viscosity. So even if two oils have the same 100C kin vis your oil pressure gauge will read higher with the oil that has the higher HTHS. Is this why Castrol 5W-40 seemed to be slightly better than M1 0W-40 at mitigating the noise?? I don't know but from the PDS I can find online it does have a slightly lower HTHS than M1 0W-40, so maybe it tickles all the nooks and cranies just right.
To the OP, apologies if this turned into a thread hijack. I just wanted to give a tip to make the noise go away based on my and another gentlemen's experience. Especially since you've covered so many items already, I would suggest experimenting with oil filter and oil brand/weight before anything else. JFP, This is good conversation, perhaps we should take this to another thread? I suspect you're generally correct, and like everyone else I would prefer 100% filtration, hence the LN adapter and spin on filter. However I don't know for sure when the factory filter bypass valve is in operation. If you have Porsche specs that detail what pressure differential across the filter media (the only pressure this valve references) causes the bypass valve to open I would love to know. I think a typical number in the industry is around 10-12 psi. Then we need to instrument both the high and low pressure side of the oil filter media to find out under what operating conditions this pressure differential really exists to open the bypass valve. Nice one! What filter is that and what total system pressure caused that level of damage to the casing? Does that filter have the bypass valve built into it or is it in the block of the car engine like many cars? Second, the filter casing sees the maximum total pressure in the system whereas if the filter bypass valve is sized adequately it can keep the pressure differential across the element low enough to prevent damage to it (once again that's pretty much its job). This is why you can split a filter canister open or blow out its seals and the element may still look OK. The critical difference between the above and our situation is the Napa Gold 1042 has no internal bypass valve, and our engine block does not have it either (because its built into the bottom of the factory reuasble plastic filter housing) so by using the spin on adapter you have changed the base system. So I believe its possible in this condition to produce enough oil flow (presumably at cold oil temps) to create a pressure differential across the filter to hurt it all while the total system pressure remains low enough that the outer casing does not deform or fail. I don't have the data to prove it explicity, but I believe its easily plausible. True, however I bet all the applications that call for this filter from the book have a filter bypass valve built into the engine block. I can't imagine any filter media designed to withstand a pressure differential across it equal to the total system pressure. I also experienced slightly higher oil pressure at warm idle with the stock oil filter. This of course is not a real surprise if the Napa 1042 is more restrictive...it will be at all conditions to varying degrees. And it was with the exact same oil since I kept the oil and only changed the filter. I also have Durametric so I know the oil temps were also equal when I referenced the pressure, which is critical for an accurate comparison. To be clear I am not advocating running the thinnest oil you can stand and still sleep at night, you can take that too far and do some real damage. From my experience the thicker HOT weight was the wrong direction, ie 0W-40 or 5W-40 was better than 5W-50. Agreed a lower HTHS is not preferable on one hand, but it does support a slightly lower viscosity was still directionally correct to stop the noise, and if you're one of the unfortunate few with this affliction, that aweful noise does not seem so preferable either! :cursing: I am certainly not here to sell Castrol or a particular oil weight, just report what worked for me and what data and experience I have to support it...if one finds something that works better for them, use it! Agreed the lifters are a dead end design, but they still require a non-zero flow rate to operate properly. They all experience some small amount of leak down in operation and when sitting with the engine off. The switchable lifters on the intake side even more so because the lock pin is dependent on oil to actuate. This is not true and a common misconception about multi weight oils. In the case of a 5W-40, the oil behaves like the viscosity a SAE 5 weight oil would at the cold test temperature, but at the hot test temperature it behaves like the viscosity of a SAE 40 weight oil. This does not mean the actual viscosity when cold is thinner than when hot. If this were true you would see your idle oil pressure rise as the engine warms. When the oil is cold you need a lightweight oil so it remains thin enough to flow adequately, but if you were to use that same oil when it gets really hot it would become "thinner than water." But of course if you have a 40 weight oil to solve the hot running condition its so thick when cold it just won't flow adequately. (This was the case way back in the day and you might have had to change your oil on a seasonal basis to compensate.) Multi weight oils transition their behavior from that of a thinner (ie SAE 5) oil to a thicker (ie SAE 40) oil as they warm BUT their actual viscosity trends thinner and thinner with increasing temperature.
JFP, I certainly understand where you are coming from. To be clear once again I harbor no ill will towards LN Engineering and Charles was kind enough to correspond with me when I first began chasing this tapping noise many years ago. Many months later when this came to light and seemingly "fixed" the issue I shared my findings with Charles but never recieved a response. That doesn't prove anything, but its not fair to share on the internet without giving the creator a chance to respond, etc. I documented all my work on another forum chasing the problem from the beginning that eventually lead to this. Further, I have a masters degree in mechanical engineering and worked professionally designing fluid systems (fuel, brakes, coolant, and oiling) for multiple professional race teams over the years, so I have a strong academic and working knowledge of these systems. I only now brought it up in hopes of helping Geflackt because I worked at solving it for far too long, and Porsche dealerships as well as Porsche specialist indy shops that looked at my car all scratch their head. I feel fairly confident its a little slop in the system that manifests only when the exact mechancial conditions are right, like the "right" (=wrong) tolerance stack up, no engine load, and too little oil flow, etc. Given that modern engines use the oil just as much like hydraulic oil to run various systems as much as for traditional lubrication they have become that much more sensitive to exact oil flow conditions. To the point, here is an exploded view of an intake lifter for our cars that I made during my efforts. You can see there are a lot of small moving parts, one is the pin that moves laterally by way of oil pressure to lock the high lift and low lift portions together. That happens at somewhere around 3200 RPM when VC+ kicks in, its not hard to imagine the hard life this component lives and how if one were a little less than perfect you could have some issues. Based on having rebuilt the heads on a few other 996/997 vehicles I have seen these lifters fall apart in my hand as they were removed and yet the engine still ran OK if not a little loud and rough. JFP I'm sure you've seen this too. At the time I only found one other gentlemen in TX experiencing the same and he said: "I first noticed the noise after changing the oil, so I assumed that it had something to do with the Pennzoil Ultra 5W-40 Euro that I had just put in, or the filter and adapter that I got from LN Engineering. As you noted from the video, the sound was terrible at first; I thought the engine was about to let go! I brought it to my local independent Porsche shop and they replaced the filter with a stock Porsche OEM unit and replaced the 5W-40 with 0W-30 thinking that one or more of the lifters was sticking and the thinner oil would help unstick it. I also added some MMO to assist in that process. The shop owner told me to drive it hard and I did (while this made me nervous with 0W-30, a UOA showed no atypical wear for the 1000 miles that the thinner oil was in). After some time the noise got quieter. I haven't driven the car in a while, but I think the noise is gone or quiet enough that I can't hear it." So, to isolate things better I only changed back to the factory oil filter and did nothing else except a little make up oil to replace what was lost in the oil filter change. The noise immediately got better. I’m sure there must be tons of these adapters out there and if this is not common there must be extenuating circumstances required for it to manifest, however I’m still not sure what that is exactly. Since my oil pressure gauge was installed after the spin on adapter was present, I had no reference oil pressure behavior with the factory system, but once I put the factory oil filter back on I immediately read about 5 psi higher cold start oil pressure at idle and even more pressure difference if you blip the throttle when it’s cold, easily passing 90 psi and still climbing. I don’t know how high it would go as I am extremely gentle on driving the car until its warm, in fact that’s a big reason I installed the gauge so I would know when the oil was fully up to temp (by way of a stabilized hot idle pressure) before driving it hard. At cold start up the spin on oil adapter only allowed the oil pressure to reach 80 psi and wouldn't pass 85 psi if you give it throttle (with 5W-XX oil). While I'm not super concerned about the cold pressure behavior, I still saw an increase at hot idle with the factory filter, which did concern me since I’m sure the filter by-pass valve and the oil pump PRV are not open. To respond to your other question/concern I guess the factory paper filter element (which agreed is definately not as substantially supported as the Napa Gold) does not experience collapse because: 1) there is a by-pass valve present precisely to prevent this. 2) it may have more surface area than the Napa Gold 1042 = potentially less restriction for the same oil flow 3) it may provide less filtration through a more open free flowing element = potentially less restrictive for the same oil flow So with the LN adapter and spin on filter given the right combination of oil weight, cold temps, and enough revs you may produce enough pressure differential across the filter element to damage it since there are no provisions for relief. From all this it was clear to me the spin on LN recommended NAPA Gold 1042 was more restrictive. So as mentioned I cut open the spin on filter I had just removed and found signs of collapse. I imagine this occured when the oil was cold, but I can’t be sure as it never got that cold where I was living at the time, typical start up temps for me during the winter were around 45-50 F. Its been a few years, this is the only picture I could find.
Geflackt, you are not alone and have just detailed essentially the same list of items I checked/replaced in my garage a few years ago based on the exact same symptoms on my '07 Cayman S. I can appreciate the effort and learning curve you speak of. I also did one more major thing and pulled the trans to check the DMF for excessive wear (which can make a somewhat similar noise) and found it to be out of spec. I replaced it to no avail. If you ever find the exact smoking gun I would love to hear what it is, but here is what I do know: It is certainly related to the oil system flow/pressure conditions as I tried multiple oil weights/brands and 3 different oil filters and they change the nature of the noise. The biggest change came from removing the LN Engineering spin on oil filter adapter with Napa Gold filter (exact filter LN recommends) and putting the stock filter system back on. This helped dramatically. I had also replaced the Sport Chrono stopwatch with a high quality Spek oil pressure gauge and upon putting the stock filter back on picked up more oil pressure across the board. Following that I cut open the Napa Gold filter and found the filter element to be crushed/collapsed, presumably from over pressurization due to no bypass valve for relief (stock valve is inside the plastic filter housing, so it gets eliminated by LN's kit). It is not my intent to blame LN whatsoever, you make your choices and accept risks, but my oil pressure data and crushed filter experience convinced me that that adapter kit is not safe and it certainly exacerbated that noise. The last "tweak" was changing to Castrol 5W-40 which is Porsche A40 (I tried multiple 0W-40, 5W-40, and 5W-50 weight oils, some Porsche A40, some not). The heavier the oil weight the worse it was, which is contrary to the usual advice of a heavier oil to fix a noisy lifter at cold idle, but then again this noise is always hot idle and never cold idle. I'm not claiming its the best oil ever or that M1 is junk but using that oil with the stock filter essentially solved the problem. After many thousand miles on rare occasion I hear a tap or two but nothing like it was. Good luck, I know I pulled my hair out trying to solve it.
I realize I'm bringing a 4 year old thread back here, you still around Gary? I have the exact same symptoms and have already been through all that's mentioned above plus some. Have a new AOS in hand but hoped to get some confirmation before burning a new part maybe unnecessarily.
Not completely. I swapped in a new valve lift solenoid on one side and then the other, didn't fix the issue so I put the originals back in and kept the new one as a spare. I also pulled out the valve timing solenoids on both sides and found bits of debris in the finger screen on Bank 1 that keeps trash from flowing into the solenoid (and ultimately the vane cell adjuster). The debris is pieces of very small lightweight spring, my guess is its part of a check valve spring somewhere. I cut open the check valve built into that finger screen but that spring was fully intact, so it didn't come from there although it was the same size. I was originally planning to just try swapping in a new valve timing solenoid until I found that debris, now I'm hunting where it came from instead. My guess is a chain tensioner but I haven't been able to confirm they have check valves in them and I haven't had time buy the cam lock tool and start pulling them out. The clacking noise is getting more constant at idle but the car still drives fine, doesn't burn oil, no CEL, nothing. Funny thing is sometimes if I push the clutch all the way to the floor the noise stops completely until the moment I release the clutch again. I can do this over and over again with the same result some days, but other days this has no effect and the clacking keeps on going with the clutch pushed in.
Over time I have also developed an intermittent hesitation just off idle, this seems to only occur when the engine and ambient is hot. I took some data with Durametric and plotted actual camshaft angle vs nominal and also post processed the data to view it as % error of nominal. I noticed from a dead cold start that both camshafts flucuate in an error band of +/- 20% while trying to maintain the requested angle. From a controls standpoint some level of flucuation makes sense. While cold I believe the valve lift is held to high to accelerate warming of the cats. When the engine warmed enough to drop the RPM to warm idle, and I believe the valve lift drops to low, I noticed that Bank 2 maintains the +/- 20% error band while Bank 1 now shows a +/- 50% error band. I have always noticed that I do not get any wierd noise or engine behavior during a cold start but only when warm. When the engine is good and hot, I also sometimes get a buzzing sound around 3200 RPM that appears to come from Bank 1 as best as I can tell. This behavior is intermittent as well and I believe this RPM coincides with when the valve changes lift from low to high. So I drove around and collected data but of course I can't ever get it to buzz while I have my laptop with me. I did notice that Bank 1 does not seem to track the requested cam angle as well as Bank 2 showing poor fidelity when the requested angle is changing direction rapidly, like going from WOT to zero throttle back to WOT. I decided to try replacing the valve lift control solenoid first. Here's my question. When I removed the solenoid from the cam cover I'm afraid the solenoid body rotated in the bracket and I noticed there is a small notch in the tip of actuator. When I swap solenoids and reinstall, where should that notch be facing? I don't see any obvious marks on the cam cover or in the solenoid bore indicating the required alignment. Thanks.
OK, thanks. I found this in reference to the 996TT switching points and wondered if it applies to the NA motors and/or changed with the newer models in general. I was trying to figure out if the switching points are purely engine speed based or also a function of load. Anyone have a similar plot a NA vcam+ motor? I'm a bit envious of those with older models as the available information seems much greater. I would love to have the correct ohm readings on hand.
It isn't throwing codes yet, but it is acting up. First randomly and over time seems to be more constant. It sounds a lot like a lifter going bad, but I've read a few posts of failing variocam systems mimicking the sound of valve lash, collapsed lifter, etc. I spoke with an indy shop that has diagnosed and confirmed this in a similar fashion, so I thought I would give it a shot before going deeper. Now I'm trying to confirm expected behavoir either through applied voltage or Durametric. Any input would be appreciated.
I haven't found any stored codes yet. Do you know what their resistance should be? I also just applied a 12.67 V source to each solenoid while they are still in the cam cover, engine off. Both lifter solenoids responded with a healthy click, like it had a good amount of force behind it. Both timing solenoids did not, one made no noise at all, and the other clicked so faintly that I really had to concentrate to hear it. Does this sound right for the timing solenoids?
Car is a '07 Cayman S and I started inspecting the two variocam plus solenoid/actuators first with the Durametric and then later with my multimeter. The valve timing solenoid read 10.7 ohms while the valve lift solenoid read 12.7 ohms. Readings from both banks were exactly the same. From old posts concerning the original single solenoid variocam system, I've read the solenoid should read about 13 ohms, but I don't know if that's true for the newer "plus" design. Anyone know? If so, then I guess that points to having two bad valve timing solenoids. When actuating each with Durametric, what should I monitor and what should I expect? So far I've concentrated on monitoring cam angle. When I actuate the valve lift while at idle it kills the motor, and I haven't tried this at higher RPM yet. When I actuate the valve timing at idle I don't really hear or feel a change, and only see a small blip on the cam angle plot that drops down from 0 to -250 on the Y axis (what are those units?), however the blip is sometimes much smaller. I'm not sure if that's real (and a problem) or a function of the sample rate. Again, I'm not sure what it should do, should it hold the timing advanced/retarded until I stop it or is just that blip normal? And in general, is it ok to unplug the electrical connector on all the solenoids and manullay actuate them from a seperate 12V source while the engine is idling?