Replacing lifters to address a misfire, some questions.

I�ll break this up into 2 posts, the first to outline the history and issue, the 2nd to pose the questions I have regarding the lifter replacement that I will do myself. I know it is a little long but having trawled posts for the last week hopefully if someone has a similar issue in the future they can relate and hopefully find the solution helpful. Some background, I purchased a 40AE (my 2nd) nearly 2 months ago, 47k mile car well looked after, no issues. After purchase I drove the car home 2,500 miles, on day 2 of the drive a CEL came up P0303, car drove fine. Had misfires on my last AE and was linked to fuel. As the car ran fine I put it down to fuel. When I got the car home I trawled through the extensive service history that came with it. Amongst the repairs was a list of repeated misfires and the work done by the last 2 owners to address them. The original purchaser had a Porsche dealer look into a misfire on cyl 4, this was around 2015 with ~40k miles. They checked many items and recommended replacing all of the lifters, the owner declined and only had the faulty lifter on #4 replaced, the also replaced O2 sensors at the time. They reported that the car ran fine. The car was sold to the PO and he has a few receipts from 2015-2017 ~45-47k miles with Porsche and Indie�s for various work including full service, IMS, clutch, water pump, thermostat. During the various services he also had the plugs and coils replaced in 2017 at around 47k miles. The last few show the specialist looking into misfires during the service work, they checked crankcase pressure and recorded 4.85, within specs. The also measured compression at 240 with �very little leakdown�. One Indy noted that the misfire was on Cyl 1 & 3. They replaced crank sensor, replaced a timing chain tensioner, swapped Variocam actuators over (presume to see if the misfire moved) and ran Swepco through before an oil change which makes me think they felt it had a lifter issue towards the end. Each time noting that it looked like the misfire was cleared. When I got it home and had to replace rad�s due to a slight leak. Whilst bleeding the system I had the car idling up to temp to open the thermostat. Whilst blipping the throttle to 5k RPM the CEL can on and at idle the car ran rough, I ran Durametric and it flagged P0300, P0301, P0303 & P0305, misfires on cyl 1,3 & 5. The car cooled a little and I cleared the codes, the car restarted and ran fine, no rough idle or stumbles, rechecked Durametric and no codes. Ran the car for 30 minutes or so, got it home and ran Durametric and checked the cam deviation, its running 0 on bank 1 and 1.43 on bank 2 so well within spec and not looking like a Variocam issue or overly worn tensioners. Driven around 400 miles trouble free running the car up to 5k rpm no issues, including a 100 mile trip. Yesterday got the car up to temp and ran it spiritedly, including taking it to 7k rpm. At one time as the revs dropped below 3k the engine CEL flashed and at idle the rough running came back, checked it and it has a P0303 cylinder misfire on #3. Cleared the code and let the car cool and it ran fine again, no CEL. So after plenty of reading and the above facts I am sure I have sticking lifters, it also makes sense when you look at the symptoms, then the car is hot and you run at high RPM when the liter is activated, it sticks and then as the revs drop it is over filling the cylinder and triggering a CEL. It cools, the lifter retracts and then it runs fine. So hopefully this thread will eventually record the repair and I sincerely hope the resolution.

If you read my first post you will have seen the history and how I got the point that I�m looking at replacing my lifters, whilst it seems to be affecting Cyl 1, 3 & 5 I�m going to replace them all, its an additional $1k in parts as they are not cheap but I get the feeling my car has a bad batch, and if your going so far as to drop the engine to replace 3 cylinders you may as well do them all and hopefully fix it once and for all. I�m going to do the work myself, whilst not having taken out a 911 engine, I am mechanically savvy and confident of the work. I have read the 996 101 projects and the Bentley and it seems pretty straight forward as long as you use the right tools and follow the process. I have a 4 post lift, so will remove/disconnect as much as possible, then roll the car onto the floor, jack it up and drop the motor for the work. So onto my questions: 1. With the engine out I plan on replacing the tensioners, all the seals and O rings, all the lifters, AOS and add a low temp thermostat. Anything else people would suggest adding to the list? 2. Looking through the manuals it shows you can replace the timing chain rail slide (one that the chain tensioner runs on), I can�t see anything about replacing the opposite timing chain rail that�s fixed. Can this be replaced with the engine out doing this work? 3. I plan to but OE parts, however I see that Pelican lists the OE exhaust lifter at $55 each and an OEM INA exhaust lifter for $20 each. Anyone use these?, are they the exact same part without the Porsche tax?. I have purchased Pelican OEM supplier parts before and they were exactly the same. It�s a $400 saving so worth looking at. So overall with buying some tools for the job and parts I�m looking at a $3,200 bill, I�m glad I�m not paying labor on top of that!! I have a few spring jobs around the house to tackle first before I inform my wife I�m spending $$ and dropping the engine out of my 2 month old 911.

Have you really ruled out everything else before you do this? lifter problems on these motors seems quite rare from what I have read. Its a pity you couldn't get the old lifters already replaced to examine them. Also don't forget the lifters run in an aluminum part that bolts into the head, I have heard of the bores becoming oval; putting new lifters in won't fix the problem if you have oval lifter bores. If I were you I would do some more logical investigation before pulling the motor and putting new lifters in. Stuff like fuel pressure, injector condition, air leaks, spark plug condition etc etc.

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^^+1^^...I've never heard of lifter problems in a M96 leading to misfires. This isn't to say "it CAN'T" happen, but...I wouldn't put $ on it. Misfires are usually related to; coils, plugs, injectors, MAF, bad fuel, etc...

I agree that you shouldn’t rule out other points, however: Fuel: This has happened over the last 3,000 miles at various times, in various states. I would suggest that rules out fuel Injector: Happens randomly with heat and revs, however when you stop the car and restart is sometimes goes. + on a steady journey including lots of traffic you get the same heat condition but no misfires. Symptoms to me feel more mechanical. Plugs & Coils: Less than a yr. old Porsche parts, admittedly they could have failed and I will be doing the swap test first. If you do a search there is quite a few 996 cases of sticking lifters causing misfires. The Variocam works on the intake, if the sliding center sticks then the valve is working in high lift mode which is fine over 3k rpm. But below that it’s overfilling the cylinder for the revs and timing and can cause the misfire condition. I been trawling the threads and it is more common than you think, where people did all the usual (plugs/coils/MAF) checks first. Then finally doing lifters after the dealer tried everything else. I also think it’s telling that the original owner has misfire issues that was finally resolved by replacing a lifter by Porsche. And subsequent owner had cyl 1 &3 misfires and took it to 2 indies +Porsche who by the look of the receipts have done all the usual replacement parts. I’d love it to be something more simple, and will for sure try all the usual suspects firs before tearing anything down and buying parts.

996.2 lifters for the intake valves are eye-wateringly expensive, and there's 12 of those. Plus, the labor involved (since doing this engine-out is nearly mandatory) costs quite a bit. Also the replacement of the valve covers is tricky, since the valve covers incorporate one half of the camshaft journals. It's an expensive job, and I'd recommend further diagnosis to confirm the lifters are the issue before committing to this repair.

"Fuel: This has happened over the last 3,000 miles at various times, in various states. I would suggest that rules out fuel" By "fuel" I didn't strictly mean the fuel itself, but the fuel system in general. You're overlooking all the stuff internal to your car including: Fuel tank, fuel pump, fuel filter(s), fuel rails, pressure regulator(s) etc... also, the injectors are electronic, so their wiring and connectors should be checked.

Thanks for the feedback, I can assure you I will be trying every avenue to fix it before open heart surgery, thats is my last resort. An easy electrical fix would make me a very happy man!! As some additional data, I tried for the last few days and can consistently trigger the misfire and CEL. Yesterday another high rev run triggered the flashing CEL and rough idle, after a few seconds idling the CEL cleared itself and idle stabilized. The car recorded a pended P0303. I’m away on business for a few days but when I get back I’ll be doing a plug and coil swap between 2 and 3, as 2 never seems to be running fine, also checking and cleaning all the electrical connections. I haven’t looking into how easy it is to get to the injectors on a X51 car. I hope that is accessible so that I can swap those and see if it changes anything.

Update, I swapped over coils, plugs and cleaner all the connectors in an attempt to diagnose and fix my misfire, but no change. I can still trigger the Cyl 3 and Cyl 1 misfire, so decided to drop the engine and do a refresh on the top end. TBH I love working on my car so call it a labor of love aside from the $ involved, just don’t tell the wife……..after all how hard can taking the engine out of a 911 be? Whilst the engine is out I’m going to do the following: Replace all intake and exhaust lifters Replace cam chain guides and rails Replace AOS Replace oil filler Replace all gaskets and seals linked to the above Fit low temp thermostat. Send the injectors out for refurb. The total parts bill comes in at $2,500, $1,500 of that total being the 12 intake lifters, which I believe is the problem I have with my misfires hence deciding if I am going to do this to replace them all. The early 3.4 engines used the same simpler lifter on both intake and exhausts, they are INA parts that you can get for $14 from Pelican. However the 3.6 whilst having a simpler variocam system has a more expensive intake lifters that costs $127 each!!. Replacing all the camchain rails and guide rails were relatively cheap at $233 from Porsche, so whilst I have the engine stripped I may as well replace those. The rest is O rings and seal + the AOS at $121 and filler tube seems expensive at $57 for a piece of plastic. I shopped around for parts for a while and found Jim Ellis Porsche to be the cheapest, I purchased most of the parts from them with a few from Pelican, overall that came is at nearly $1,000 cheaper than my local Porsche store quoted. The Jim ellis website is great for looking up parts diagrams and their parts manager Daniel was super helpful over email whilst I was sorting out my order. All parts are ordered and expect to have it all by next week. I fortunately have a 4 post lift, originally I thought I would disconnect and remove most parts on that then push it onto the floor and jack the car up to remove it. But when it was up on the lift it looked like with some work I could drop the engine through the lift rails. Drove the car on the car on the lift around 11am last Friday and started work, there are a lot of videos and tutorials on removing the engine, I won’t go into every detail as A, I didn’t take pics of everything I did and B I probably forgot a few steps. I’ll summarize it below, but overall its pretty logical and I’d suggest easy. 1. Drain oil, whilst thats draining: 2. Disconnect battery, remove airbox, serp belt, rear bumper & heat shields & mufflers. 3. Drain coolant and disconnect thermostat hose, whilst that’s draining: 4. Drain PS reservoir and remove, to remove the reservoir on the X51 engine I had to remove T body, intake plenum to give better access. 5. Disconnect O2 sensors, SAI, harness connectors, brake booster, fuel rail, 6. With the intake plenum off you can reach behind the AC compressor to find the hidden bolt at the back, then a 13mm socket on an extension through the bank 2 intake manifold temp sensor hole reaches the socket to remove the compressor. Rest this on the outside of the car then you don’t have to mess about with evacuating/filling the AC system. 7. Remove the headers and lower muffler mount screws, as once the engine is on the stand these would be tough to get to. 8. Jack up and place rear on jack stands 9. Disconnect/remove: wheels, undertrays, chassis crossmember, chassis diagonal braces, rear sway bar, rear drive shafts, gearchange cables and reversing light switch. 10. Remove coolant lines connecting the engine to chassis, there are a few, but easy to get at, 11. I used a MC bike stand under the engine and supported it on wooden blocks and raised it to support the engine and transmission. 12. Remove the front transmission mounts nuts attaching it to the chassis, and rear engine mounts, clearly make sure the stand fully supports the engine! 13. Lower the engine a few inches 14. Now you have better access to the clutch slave cylinder to remove it. 15. Finally disconnect the PS lines which are top RHS of the engine bay, dropping the engine a little gives much better access. These are brass fittings 19mm and 15mm I think. I would suggest getting a set of box flare wrenches as these fitting and very soft and its very early to damage the nuts. My car’s engine was already dropped by Porsche a few years back and the tech had slightly rounded the 15mm brass nut. So take care and get the right wrenches. 16. Lower the engine gradually and make sure you haven’t forgotten something connecting the engine to the car!! All in all I was pretty easy, I took my time. Bagged every nut and bolt in notated zip locks and checked everything repeatedly. By 5pm the engine was out. I am sure experienced tech drop them in � that time. With the engine lowered out of the car, the muffler mounts and coil shields removed, I only needed to take � of an inch off the lift inner rails (sill leave 2+ inches so I have no fears of damaging the lift) and the engine was out. So on reflection: “how hard can taking the engine out of a 911 be?” ……its pretty easy with basic tools and common sense. More to come……

Last night for once I didn’t have a kids soccer game or track meet to attend, so had a chance to start stripping the engine. However, I was listening to Pearl Jam and ran the battery out on the phone so didn’t take all the pics I wanted. I’ll post some more over the weekend. My car’s history shows that it had a new clutch RMS & RND IMS fitted by Porsche last year around 5k miles ago, however under the car you could see some dampness around the bellhousing, so I pulled the transmission off first to check it out. The RMS is good but it looks like the IMS is weeping from either the flange seal or the lower flange bolts, new flange seal ordered from Jim Ellis, there have been great and added it to my existing order. Next removed the injectors, they were pretty tough to pull them out of the rails, how on earth you do this with the engine in the car is anyone’s guess. I also had the added the attraction to smelling of gas as I splashed it over my T shirt getting them off. They were bagged up and sent off to WitcHunter, $22 an injector, clean them and send them back with new O rings with a before and after flow report. Onto Bank 1, removed the following (I think in this order, however follow a manual not me!) 1. Remove coils, plugs, valve and can actuators. 2. Remove cam plugs, pinned engine in cyl 1 TDC, if the cam locking tool doesn’t fit rotate the crank another 360 degrees. 3. Remove scavenge oil pump 4. Remove cam cover, watch out for oil on removal. 5. Loosen intake and exhaust cam sprocket bolts 6. Remove cam chain tensioner, watch out for oil on removal 7. Remove cam chain guide (bolts also secure the cam caps) 8. Remove cam sprocket bolts, remove cam locking tool 9. Remove note cam cap location and orientation, then remove At this stage my phone died, just as it gets interesting! 10. Lift out cams and sprockets, be careful as if the engine is flat on a bench the cams and lifters can fall out. 11. Remove lifters 12. Remove cam chain fixed and sliding tensioner rails Following the manual the above didn’t take long at all about an hr I would say. Cams showed normal wear on the lobes and journals. Camchain guide and rails were in good condition for 53k miles, with some wear, I’ll post some pics later. Lifters showed normal wear on the bores. I’m happy to say that I feel vindicated on undertaking this task, Cyl 3 had a jammed intake lifter even when cold, I could push with my thumb the center of all the other intake lifters, but this one was jammed solid, and the center was raised by ~0.2-0.5mm vs the others. I’ll post pics to show this. I’m sure this was causing my misfire codes as the intake valve on Cyl 3 was always in high lift mode even at idle, so over filling the cylinder I called it quits for the night at this stage, Bank 2 stripdown to follow, one think I did notice was to get to the camchain rail bolts on bank 2 you need to remove the oil pump housing…another email to Jim Ellis and a few extra seals to the parts order!

Wow, amazing work. And good it wasn't a waste of time; it would be good if you could examine the failed lifter to see if there was a root cause of the problem, it might help someone else on the forum in the future.

I purchased a cheap boroscope from Amazon, great to see that the bores all look in great condition, a helpful tool for $35 Here are the chain rails and guides, very little wear for 53k miles, but they do have the strange material breakdown that these Porsche parts seem to suffer from, be interesting to know if this is age or wear related Here are the lifters, the intake on the top exhaust on the bottom, as mentioned earlier the 3.4 uses the bottom style lifter for both intake and exhaust In normal operation the center seaction raises and lowers with the lifter opening the valve, then above ~3k rpm a pin locks the lifter in the closed/lowered position giving the valve extra lift my bad lifter is on the right below, with real force I can get it to open but it’s definitely sticking vs the others. The pin isn’t sticking or locked so I do t think it’s oil contamination or debris, if you look below it doesn’t close flush like the good lifters. I think the issue may be that the center section deforms slightly where the can lobe runs on it, closing up the clearance causing it to ‘stick’ , this would the mean the valve is opening at full lift at lower rpm’s. Overfilling the cylinder and running rich causing the misfire

Nice work! Do you have the timing tools for when you go back together? I would also advise to replace the diamond washer on the cam adjusters. Possibly also check/replace your oil screens while youre in there.You may have already done all this, not sure just thought it would be worth mentioning.

Great write up! Thanks for sharing.

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Yes on the 3.6 the cam locking tools set the timing, not as complex as the 3.4. And yes i�ve ordered replacement seals, washers and gaskets wherever possible

Removed the bank 2 lifters its pretty much the same as bank 1 that I noted above, the main change is you have to remove the oil pump housing to get to the bolts that hold the chain rails, here is the location of one of the fixed rail bolts with the housing removed. you have to be careful removing the housing as it supports the end of the IMS shaft, you can see it below. With both sets of cams out, I removed the IMS tensioner to relax the pressure on the IMS chain, I had to do this as I was removing the IMS flange as well that supports the shaft at the transmission end. Found the IMS leak I had was coming from the flange bolts, bolt on the left was the top mount, which was dry. Right was the bottom right which was weeping, you can see the oil had passed and contaminated the encapsulation. Finally, my cars service receipts show that the original owner had a lifter replaced on Cyl 4, Porsche changed the part and part # to 99610525525. Still an INA part, but you can see the changes. New part on the right vs old on left

Excellent work my friend! I also had that issue on cylinder for on my 996. They originally diagnosed it as some other cylinder fuel or spark related issue. I told the technician to take a look at the lifters before pulling the engine and pulling the head (which is what they recommended!). They were surprised to find that it was the lifter. I don�t go back to them anymore. Ha

Just like a kid a Christmas, getting a box of nice new Porsche parts is a thing of joy, just waiting on the refurbed injectors Refitting the cams, lifters and chain sliders is pretty straight forward, I started on bank 2, as that was the last one I removed and needed to fit the chain sliders to get the oil pump on to stabilize the IMS shaft. Process as follows 1. Set the crank at TDC, mine was already pinned from the removal. 2. Clean the old sealant off the head, I use a razor blade and shave the sealant off, you have to be really careful not to scratch the surface. After that I clean off the residue with a scotchbrite pad. 3. Now wipe the head down, it needs to be spotless. 4. Fit the new cam chain sliders with new O rings on the bolts, I left the outermost (closest to the cam cover) bolt out to give a little more chain slack for assembly. 5. Refitted the oil pump housing with new O rings and gaskets. 6. Now with the IMS shaft supported at the flange and oil pump housing, refit the IMS tensioner with new O ring and aluminum seal. 7. Clean the lifter bores again, oil the new lifters with fresh engine oil, fit the intake first. 8. Now place the intake cam in the head, cyl 4 lobes face inwards, I loosely fitted a cam cap to hold it in place. 9. Fit the exhaust lifters and cam, cyl 4 lobes facing inwards. I found it easier to fit the cam without he sprocket, then with the cam in place you can slide the sprocket on. 10. I then cleaned an oiled the cam caps, also clean out the cam cap bolt holes and bolts. As they will be covered in oil, and you can over torque and stretch them. Fit the caps in the exact place you removed them. I marked mine 1 to 4. Fit the caps and chain guard finger tight. 11. Fit the cam locking tool, and fit the cam sprocket bolts again finger tight. 12. Fit the outermost chain slider bolt with a new O ring. 13. Now gradually torque the cam cap bolt and tighten the cam lock tool. 14. Fit the chain tensioner with new O rings and seal 15. Your cams are now set in place, torque up the exhaust sprocket, make sure the bolts are in the center of the groove, so the cam bolt is not binding on the edge, I�ll add a pic later to help explain this. 16. Now tighten the intake, there is a tool in the kit that holds this, you need to replace the bolt as the are 1 time stretch bolts. You torque it to 50nm then remove the sprocket holding tool and torque it another 110 degrees. 17. I then cleaned and refitted my cam cover, I will remove it and seal it once I have bank 1 done. 18. Remove the cam locking tool. 19. Rotate the crank 360 and refit bank 1 Here is a pic of my bank 1 part way through the process. Id suggest you also check your cam sensors, whilst I didn�t have any leaks my bank 2 seems to have failed and oil is leaking into the connector, an easy replacement Apologize in advance for the iPad induced typos

Looking good! What caused the scoring/scratches on the lifter(s) ? Did you change/update the oil pump drive key while you were in there? If not, you shoyuld do it before putting the engine back in the car - literally a 10 min. job... (3.6 may have the updated key already...)

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In reality the scratches were very minimal, I think the flash highlights them in the pic. I thought about the oil pump drive, checked it over and the original part is unmarked so decided to run with it.

The longest part of this job is next, sealing the cam covers. They have to be spotless without any traces of oil to reseal. I used a razor blade first to gently shave the old sealant off, then I cut up small sections of a scotchbrite pad (1 inch x1 Inch), dipped in denatured alcohol. Also don�t forget to clean the sealant out of the bolt holes. Follow that by a wipe down, then blow the cam covers off with an airline. Clean the sealing surface with a cloth and DA, I repeated this 3x to make sure every trace of oil is removed, this photo came out a little weird, but you can see how clean you need to get it. Same for the head, repeatedly wipe down the sealing surface. I used Loctite 5900, you only need to run a very think 1.5mm bead to seal, a small amount goes a very long way when bolted up and the 2 surfaces are almost perfectly matched, don�t think more is better. After applying the sealant I smeared clean oil on the bearing journals just before bolting up. Then gradually increase the bolt torque in the correct sequence to the correct torque level. Refitted the cylinder head oil pumps, look at the mess on this one, this was on bank 2 where a Porsche garage/tech had covered the sealing surface in sealant instead of replacing a $4 O ring!. Oil pumps cleaned up with new O rings, and new cam plugs fitted, slowly getting there.

Great write up, thanks for sharing!

Repair manuals say to set the cams in place with the crank at 60 degrees BTDC, then rotate the engine to TDC and lock things down. Looks like you just skipped this and set things up at TDC, which I've also heard. I assume the 60 degree methodology is to avoid accidental contact between valves and pistons, and turning the crank from 60 BTDC to TDC also ensures that any slack is removed from the changer. Anyone care to comment on the preferred method?

There is no risk of valves hitting the pistons during this part as none of the valves are open, setting the cams with the crank at 60 degrees BTDC just ensures the chain slack is completely taken out before tightening up the cam sprockets (as the chain tensionsers are in place and your basically locking the cams in place and rotating the sprockets a few degrees on the end on the cams to ensure everything is aligned correctly. For bank 2 I just left it pinned at TDC from when I removed the cams, then refitted them. When I went onto bank 1 I had to rotate the crank 360 degrees, I probably did it around 340 ish, didn't pin the crank, fitted the cams then rotated it the last few degrees and pinned it before tightening up the sprockets. Once completed I rotated the engine a few times to check everything out and at TDC cams on both bank 1 & 2 are correctly aligned. The 101 repair book mentioned the BTDC process, but it wasn't covered in the Bentley it just says to pin it at TDC. One thing I found unclear in both was the fit one bank then rotate the crank 360 before doing the other bank. to be safe I took a picture of the Bank 1, before removal and the same for bank 2. My logic being if I put them back together with the cams in the exact same spot I should be good I would also note that when I removed the cams and first tried to fit the cam locking tool with the crank pinned at TDC my cams were slightly out of line, I ended up having to fit the cam locking tool without pinning the crank as it was a few degrees out.

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Unless one screws up. ;-) I think the 60 pre-TDC may be as much to avoid mistakes as it is to help with correct chain tension...a "best practice" Me too. But makes sense if you think about it. When you set bank two, you are setting it at "overlap" (aka between the exhaust stroke and the intake stroke). Turning the crank 360 degrees turns the cams 180 degrees, so the 360 spin moves #4 from overlap to the end of the compression stroke (aka right when the spark fires for the power stroke). Then you set the #1 cylinder to overlap. Without the 360 spin of the crank, both cylinder 1 and 4 would be set up to fire at the same time, rather one fire on one rotation and the other fire on the next rotation. Does that make sense? https://en.wikipedia.org/wiki/Valve_timing

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Yes makes sense, I understand the overlap, I just think the Bentley isnt very clear in explaining that.

Wrapping up the engine now, still waiting for the injectors. Fitted the cam and valve actuators with new O rings and seals, followed by the plugs and coils, these were replaced by the PO last year ~3,500 miles ago In hindsight I wish I has washed the engine down before disassembly, is not really oily or dirty and I never really noticed it when I first dropped the engine. New AOS fitted, I can only imagine how difficult this is with the engine in the car even with the transmission out Next the oil filler, I replaced this on my last 40 AE whilst in the car and it was a horrible job, surely its easy with the engine out, well no its not really, you can see the rearmost bolt easier but its still tough to get to. Maybe there is a simpler way by removing the PS pump, but I just went at it as is, once the front (front of the car) bolt is out you can just get a socket on at an angle and remove this bugger, easy to see tough to get a socket on Mine was sweating so glad I replaced it, getting the front bolt in was easy, for the rear I binned the hex M6 and went for a cap head so that I could use a ball socket. went for a non stainless so I could drop in in place with a magnet, then it was pretty easy to tighten up with a ball end allen wrench Finally went to replace the oil cooler O rings, I ordered 1 large and 1 smaller O ring only to find out it needs 2 of each, I need to order replacement flywheel bolts as I forgot them as well, so 2 more O rings to the order. Hopefully get them next week and the injectors arrive and we should be ready to put it back in the car.

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Totally agree. Not just Bentley. No source I have found spells it out; they all say to rotate the engine 360 between timing the banks, but I would think a little verbiage on *why* might help folks understand the process a little better.

As the title suggests, received the injectors today. Having not sent injectors for refurb before so not sure how much improvement is expected. Doesn't look like they were so bad before cleaning. But glad to know they are all pretty closely matched now and a little more flow than before.

Whilst waiting for the oil cooler O rings and flywheel bolts fitted the injectors and wired them up with the coils and actuators. There is alot to reconnect, so placed some tape on everything that needs hooking up, should make it harder to miss something.

Excellent write up! Learned some along the way...hope I never need to do this! Chris

brass wire brushes work excellent to remove silicone from the sealing surfaces. Those injectors were fine before, and their fine now. Cheap peace of mind.

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Thanks Chris, I actually enjoy working on the car its the paying for the parts that gives me heartburn Yes, I can only imagine that they are very difficult to work on with the engine in the car. There was a small risk that the misfire that triggered all this work could have been injector related, this proves it wasn't. As you say cheap peace of mind not only that they are now matched but also worth it to replace the 14yr old O rings. I haven't checked but I would place a bet that 2 Porsche O rings per injector would be more than the $22 that WhitchHunter charged for the refurb.

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I still think the cleaning is very worthwhile, as far as I know the ECU can only do gross adjustments of fuel across banks of cylinders, it can't index individual injectors and tune them. The most important thing is to have groups of injectors on each bank with very similar flow, this way when the ECU tunes that bank you can be sure they all follow so fuel to air ratio is good. If a bank has outliers that cylinder may run continually rich or lean.

Whilst not originally planned, whilst the engine is out decided to replace the oil cooler O rings Glad I did, whilst I didn't have any leaking years of heat and compression had taken their toll, Clutch was is perfect condition, replaced by the PO ~3,500 miles ago. Lightly cleaned up the flywheel with a 120 pad. Simple plate to hold it in place to torque up the new flywheel bolts, they are 1 time use stretch bolts. Disc and pressure plate on next. With the transmission on a scissor jack and up to the right height I expected it to slide on with some jiggling. But for the life of me I couldn't get it on with muscle alone (not that I have any of that). Some mechanical leverage was my next choice. I lined the tranny up to the right height and exactly parallel to the engine I could push it in all but 1 1/2 inches, next place the mounting bolts in place and gradually tightened them 1/2 each from side to side. It tightened up really easy and you could tell nothing was binding up. All torqued up and ready to go into the car starting tomorrow.

Solid!

Good stuff!

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Cheers, your a man after my own heart with the MC's in your signature. Picked up its big brother the Jap import RZV500 that I'm trying to restore in between messing with the 996. I didn't get my # right however on theDucati front as mines a 916

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Always drooled for an rz500 or a Gamma 500! You know what they say, "great minds.." lol. More likely we have issues, albeit good ones

Nice, reminds me of the old days when I had a Daytona 500 (scary bike) I wish I never sold it but after almost getting T-boned by a lost tourist looking at a map and driving!

Wheeled the engine under the car around 9.30 yesterday morning, and had it running by 6pm Some items took longer than expected, but overall it all went together pretty well without too many issues. First think I had to do was line up the engine under the car, in my enthusiasm to pull the engine out I didnt mark the stand position on the floor, a couple of drop lines from teh mounting bolts fixed that. With the engine raised to within around 3-4 inches of the mounting you can pretty much reconnect everything, I must say the painters tape on every connection made remembering everything thing to hook much easier. Couple of tips, this one more for removing the AC condenser, the 2 front bolts are easy, the rear is blind but the easiest way to get at it is with a long extension through the temp sensor bung on the bank 2 manifold, then with the plenum removed you can feel the bolt with your left hand Fitting the plenum, push the rubbers past teh edge of the plenum, it makes it easier to get in place, then you can slide the rubbers back out. By 1pm it was bolted up in place, still alot of work to go The clutch slave cylinder proved to be a bit of a PITA, I ended up draining the fluid out of it so that I could depress the plunger and mount it up, then needed to bleed it. Not the end of the world but time consuming. Fitting the headers on your own is fun to say the least, one tip is use a bit of painters tape to hold the manifold gasket in place, then one you get a bolt in place to hold it you can pull the tape out. You also have to fit the LH header first, I wrestled with the RH side only to find this out and have to remove it The remainder of the time was refitting, reconnecting and refilling. Firing it up for the first time was a bit worrying, it took a fair few turns to fire. which made me start questioning if I screwed something up. But it did fire and ran fine, I did the LN recommended, start and shut off 5x. Once it was idling I did the worried leak search under the car but nothing, 4-5 bar oil pressure and no warning lights. After a minute of running I shut it off, did another search under the car for any issues. Then topped up and check the oil, water & PS fluid. Finally before calling it a night ran the car for a few miles, again all good no issues, no CEL's time for a beer and call it a night. Hopefully today I'll be able to finish it up, refit the bumpers and undertrays. Then take it for a longer run.

I can only say that this has been impressive and very inspirational! Good job! And nice work area....

This is a timeless tale of a man and his Porsche, Great stuff in here for anyone who might want to take this on themselves!

Thanks guys, hopefully it will encourage others to give it a go, is not too difficult with basic tools. Glad to say that there were no leaks under the car this morning. finished off fitting the rear bumper and undertrays. Took the car for a 15 mile run, ran it to over 4k RPM to ensure the variocam triggers and happy taht there were no CELs. On getting home I ran the Durametric to check the Cam variation and its running at 1.72 & 2.02, well within specifications but honestly I was expecting it to be better. The car runs great and I am very pleased with it. Going to take it easy for 500 miles then dump the oil and filter + drop the sump and make sure everything is cleaned up. After that I will get it hot and run it hard which used to trigger the misfire and CEL. Total it cost me $2,694, $2,641 in parts, + $323 for the Injectors, LN low temp thermostat, oil, PS fluid and 5900 sealer. I'm sure it would have been a $6k job at a dealer. I could have done the intake lifters on the misfiring cylinders only for $500-600. But I think if your going to do a job do it properly. All ready now for some summer useage

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Don't be too hard on yourself. Your cam timing numbers are great. It's damn near impossible to have them be zero. Most new engines end up with a 1 to 2 degree variation :-) Good job! Good taste in cars - love the Audi as well.

I have completed 400 miles since the rebuild, I dropped the sump to check it out and changed the oil and filter (the oil will be going in the Audi at its next change). When you look at the sealant around the sump it is aged and looks very much like the sump has never been removed. Pretty clean, no glitter. there were the following pieces in the bottom The 2 larger pieces are clear brown plastic that is quite brittle. It doesn't look like chain guide material, not sure what that is. The 6 black pieces are hard plastic, looks very much like the chain guide material and would align with the slight wear I had on the guides. The bottom left is aluminium, it looks just like machining swarf and is the only metallic material in the sump. With fresh oil in the car got it up to temp and drove it hard in the lower gears all the way to 7k rpm, car feels great. This hard driving used to without fail trigger the misfire CEL in the past. Got it home and plugged in the Durametric and all is clear, no CELs or pending. So I am very please to say its fixed, hopefully this is helpful is you have a 3.6 with a persistent CEL that cant be addressed by the usual plugs and coils.

Also meant to add, I decided to go back to the OE oil filter, it is just so much easier to dissect filters than the LN screw on filter adapter. So if anyone is interested I have a LN adapter for sale with only 400 miles on it. It clearly works great and is a beautifully machined part.

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what would you like $ for the adapter? I'm in minnetrista. Joe

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PM�d you

Nice work! Good luck with 'er... The brownish plastic looks like it was from the old cam chain tensioner pads (they start out whitish and turn brown with age/heat)... nothing to worry about as you've already changed them...

I've gone back to the stock filter also. The filters from Porsche now come with the housing for about $35. I have an adapter plate and tool to open the metal filters if someone is interested.

My hat is off to you. I have done 30+ engine drops on my four post lift but never one in between the ramps. I am in the middle of one right now, and earlier 996 5 chain engine. I was looking for disassembly instruction but it looks like the engine is very much different.

Great work, thanks for sharing.

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There are a bunch of posts/topics covering engine drop on jack-stands. Do a search, you'll find 'em. It's pretty straight forward - lots to remove, but nothing too difficult. Good luck

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Who has the OEM plastic filter housing for $35? I might buy a new one as mine is 18 years old at this point. Thanks

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I have no problem with removing engine. Do that all day. I removed the engine last week on a 4 post lift with the engine hanging off the rear. it's the disassembly of the 996-01 cam shafts that I am looking for. I did find some useful references and got what I needed

I don't know if you saw this one, https://rennlist.com/forums/996-foru...urametric.html This was my experience with the dreaded 1341 code. Long thread but covers a lot of what you're looking for...

So, have you had any other missfire since you put everything back together again?

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No, pleased to say all fixed with over 1,000 since the work. Getting it hot and driving it hard causes absolutely no issues. Where before it would flag a cell and misfire.

Pelican has the filter housing combo for $22.75.

Great write up. Since you have done so much to address your issue, figure reaching out for an advice. I have been dealing with intermittent random misfire for over 6 months now. It is a 2001 3.4L C4 with 100,000k miles. I have checked the following: -Fuel pressure -New MAF -New crank sensor -New fuel injecters, -New plugs+coils -New DME and Injector relays -Check vacuum and fule trims -Oxygen sensor response looks normal -cam deviation at -3, and +4 -new fuel filter -cold compression test all around 138 psi -leak down test on all less then 8% The misfire is very intermittent and random from cylinder to cylinder, all 6 of them. I do notice there is tapping noise some time, but not all the time. When I hear the tapping, it will clear when I light increase the RPM. No misfire when doing spirited run. It always happen when cruising around 1800 rpm to 2800 rpm. The faults codes are always the P0300 plus a couple P0301 to 6 randomly. There is no other codes that come with the misfires. Question 1. Do you think it is the Variocam got anything to do with this, since this always happen at the time advancement range(Variocam, not the plus), though no other code? Question 2. What is chance do you think that all lifters are failing? 3. Another thing I am thinking is a faulty DME. As you described in your first post" So after plenty of reading and the above facts I am sure I have sticking lifters, it also makes sense when you look at the symptoms, then the car is hot and you run at high RPM when the liter is activated, it sticks and then as the revs drop it is over filling the cylinder and triggering a CEL. It cools, the lifter retracts and then it runs fine. " Can you explain a little bit or point me to other reading on why you were so sure it was the lifters? Any feedback would be great to help me in solving this dreaded random misfire. Thanks.

i'm sure you will get feedback from others more knowledgeable than me, but there's been lots of discussions lately about the "tapping sound" you are describing. look at a recent post "tap, tap, tap". best of luck.

Great thread! It would be nice to get an update on the status of the car after all of this work. Hope everything is still on the positive. I have to admit, I had apprehension as to whether there would be a less than desirable outcome after being driven for a while. Certainly hope those fears are unfounded. ...tagged for future reference...

I would do a bore scope check just to rule out any cylinder problems , if you have some scoring it can allow oil through to cause misfires , worth checking if you've exhausted so many other avenues!

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Snag an audio recording when you do hear the tapping noise and post here, please. Random misfires on 1-6 is not a normal occurrence with bore scoring as far as I know. How did the plugs look when removed?

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I could be wrong, but your cam deviations are out of spec. Spec is a 6 degree delta.

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I was just looking through this thread as I'm thinking about selling the car. It's got an additional 5,000 mile on it since I didn't the engine work and it's running perfectly, no more misfires or cel's!!! The sticking lifter was definitely what was causing my problems.

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That's good news. But why sell it now?

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I just fancy something different, I'm pretty sure I'll sell it, but something else and then hanker for another 996. If there was a serial car buyers anonymous I would be going to the meetings every week!, I think I'm up to 54 cars over the last 24 yrs.

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I am the complete opposite. I still have just about every race car I've ever owned, or built. And it covers a lot more than 24 years...

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So which has been your favorite? I�m all the trying out different cars, and I�ve had 10 in 25 years, but then now, my 996 has been the car that I cannot easily replace with something better in this price range.

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Out of the 55 I have has a fair few crap cars to be fair. I have only purchased the exact same car once.......the 996 40th!, the car I have kept the longest and still have is a BMW E90 328, nothing particularly special about it but it just works. The 2 that stand out would be the BMW E39 M5 I had and sold to move house about 8 yrs ago, and the Audi S8 with the V10 engine that got totaled a few years ago in the snow.

Good luck with the sale of your 40th. I enjoyed reading through your posts and learning so much about our cars. I really like your suspension set up and will likely do the same for mine. Was there significant issues with the car being lower- I realize you need to be more careful but closing in that gap on those wheel wells and the car driving experience has got to be worth it Thanks TG

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I think the ride height have now is very similar to a GT3, so no issues with day to day driving. I'm just more careful with low curbs, something all of us are aware of with a 911

Does anyone know if the lifters can be replaced with the engine still in the car, particularly on bank 1?

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I cant be done in the car, engine needs removing which is the bulk of the labor vs the actual repair itself