I just finished replacing my Variocam chain pads on my 2000 Boxster 2.7 WITHOUT taking the engine out of the car and would like to share what I learned. Most of the write-ups, forum posts, and videos assume the engine is out of the car. I wanted to try it with the engine in the car for many reasons: I don't have a lift, I don't have an appropriate lift table to lower the engine, and I have no place to work on the engine once it is out and the car is disabled. Also I thought it may be faster to not bother with removing the engine and liked the challenge implied by forum posts about how difficult it was. I am a moderately skilled hobby mechanic and this was the biggest job I had ever considered - and happy to report it is done and went well with lots of little challenges along the way.
My intent with this DIY is to add little tips to get past these challenges. I am not going to reiterate the basic procedures that are very well documented online and in print. I can refer you to the Pelican DIY which is on their website and depicted in the "101 Projects" book, both excellent. My favorite video is "Don't neglect wear pads! How to fix camshaft deviation | Porsche 996/986 w/5-CHAIN ENGINES ONLY!" with Jake Raby, published by Porsche Club of America on YouTube. It depicts a 996 engine but the steps of the heart of the job are the same. Also "Porsche CAM TIMING CHAIN GUIDE RAIL Replacement/Install" by 'Help me DIY" on YouTube. He does the unthinkable, does the job with the engine in the car and films the entire thing, unedited, maybe 12 hours of footage complete with the struggles we all know but few people show in their videos. I also had the Porsche repair manual, downloaded and printed.
First off parts:
996-105-253-00 Porsche Guide Rail Set For Camshaft Adjuster x 2 (cam pads, the thing we are going after!)
999-701-647-40 green O-rings for chain pads x 2
996-105-170-54 Timing Chain - Cam to Cam / Single Row X 2
900-123-147-30 Tensioner crush washer silver x 2
996-104-215-54 Camshaft Head Plug (Green camshaft End Plug) X 6
999-707-554-40 O-Ring for Engine Oil scavenger Pumps 95 X 2.5 mm (Secondary Pumps) X 2
996-105-223-52 Camshaft actuator solenoid flange with oil seal Cover Piece/Flange on Valve Cover (2 Per Car) X 2
PAF-008-124 cam sprockets bolts 14 Nm
996-111-107-55 exhaust manifold gasket x 2
996-113-113-00 triangle exhaust manifold to second cat pipe gasket x 2
999-084-052-02 M8x1.25 nuts x 4 nut triangle exhaust joint
900-074-287-02 M8x1.25 bolt x 2 triangle exhaust joint
From eBay/Amazon/etc:
M6-1.0 x 45mm Flat Head Hex Socket Cap Screws for cam holding bar across cams when cam cover is off, these have big head, also called furniture bolts, very handy also to create 'shelf' by screwing in to head when replacing cams onto the head, they hold the cams roughly in place while you fiddle with getting the actuator in place. They are not included in the tool kit.
M8-1.25 x 30mm bolts to hold jig at the end of the cams, also the bolts that go into the ends of the cams were too short, these worked great. They are not included in the tool kit.
M5 Fully Threaded Rod, 250mm Length, 0.8mm Thread Pitch, Left Hand Threads, I cut this rod in half, only needed about 125mm, used to compress the variocam piston, very handy. Older cars had a different way to compress the actuator
M5 x0.8 left hand thread nuts for the rod
32mm Socket for Ecotec,TDI,VW,Audi,BMW,Polaris,GM,Volkswagen,Ponti ac Chevrolet,Saturn,Pontiac,Saab,Chevy, Oil Filter Socket for Oil Change, this worked perfectly for the tensioner removal/replacement
CAMSHAFT ALIGNMENT Engine Timing Tool Kit For Porsche 911/Boxster 996/997/987CAMSHAFT ALIGNMENT Engine Timing Tool Kit For Porsche 911/Boxster 996/997/987 - this seems to be the same tool kit available in a many places, shown with a molded blue case, the only parts I was able to use were the crossbars to hold the cams in, and the jig that holds the ends of the cams in - I had to use the M8-1.25 30mm bolts(above) as they did not include the center bolt and the two bolts for the end were too short
RV Scissor Jack Kit, 5,000 lbs. 24" Extended. This is used to hold the front of the engine as it is released from the motor mounts. These jacks are used to level camper trailers and have a metal platform at the top,I screwed a 2x4 block about 10" long to the platform.
Engine oil, filter
Loctite 1158514 Head Bolt and Water Jacket Sealant under the heads of the cam cover bolts to prevent leakage out the bolt holes
Loctite 4741 primer/activator for cam cover flanges, helps Loctite 518 cure
Loctite 518 Red Gasket Eliminator flange sealant
Disposable Glue Brushes 1/4" to spread flange sealant
Get started:
jack up, jack stands at 20 inches on jack/lift pads x 4, this was a good height for my longish arms, very comfortable. Leave room on the rear two jack stands to access 15mm bolt for the diagonal brace which must be removed
Drop engine:
I started the job without dropping the engine and it was maddeningly difficult to get to the green cam caps and bolts on the top of bank 1 cam cover, mirror to see them, super tight to get a ratchet and socket on them so I ended up dropping the engine 2-1/2" in the front, 3/4" at the rear and it all opened up to the point I could visualize and reach all of the bolts and get them off without too much trouble. It also made replacing the cam cover without mucking up the sealant on the flange much easier.
The challenge is dropping the engine is not breaking any of the 20 or so lines/wires/hoses that course from the engine to the body. Here's what I did:
Loosen clips and brackets that hold the PS lines and vacuum lines that travel along the bulkhead, driver side front bottom of engine compartment. These are right near the oil pump for Bank 2. This was easy to do and lets the lines come down with the engine nicely.
Remove air intake snorkel from TB and air box, 8mm, may not be needed, not sure, I did it.
Remove headers, this disconnects the engine from the muffler and allows the engine to move freely, also the headers and cat block the cam covers and make the job much easier:
Remove center plastic under-body trays/covers for water pump area and the long cover in front of that to expose coolant pipes
Loosen brackets x 2 that hold coolant hoses and pipes so they can lower with the engine
Place RV Scissor Jack at the front of the engine, I like the bosses where the cases are joined along with the front lip of the oil pan
15mm remove 4 nuts that hold the front motor mount to the car, leave the mount attached to the engine
15mm remove diagonal braces and stiffener plate
Floor jack under transmission
15mm remove bolts holding transmission mount wings to transmission, no need to completely remove these mounts
Place 1/4" thick by 10" board on frame crossmember to cushion transmission, lower transmission until it rests on the frame crossmember
Go back to the scissor jack and slowly lower the front of the engine, watch the hoses and lines and listen for things breaking.
I ended up with 2-1/2" drop at the front, maximum in rear was 3/4" as the transmission hits the frame crossmember
Once the engine is down a bit:
Remove top of PS reservoir to allow access to A/C bolt. Getting this little guy out is way easier with the engine lowered.
Loosen A/C compressor, one bolt between intake manifold runners, two bolts up front angled toward driver side, to allow access to the bank 2 tensioner. I ended up lifting the compressor up about 2 inches and putting wooden blocks in to keep it there so I could get at the bank 2 tensioner.
Remove plastic green cam cover caps x 6. This was very difficult and frustrating. Given the proximity of the car frame I couldn't get a good angle on the caps with any tool. Also it turns out these caps are only 'puncture-able' in the very center, on the back of them is a metal reinforcing washer with an open center. I accidentally pushed one into the engine, luckily I was on my way in there so it later fell out. My best tool was a screwdriver that had a partially broken tip so it had a sharp diagonal tip and I could puncture and pry the caps out. Still not easy, about a 10 inch thin but strong awl would be best.
Holding the engine at TDC:
Placing the pin from the toolkit into the oblong hole was impossible, no clearance, I used an 8mm bolt, it was the exact same diameter
I took out all of the spark plugs and removed the serpentine belt so the engine was easier to turn over
Bank 1 Passenger side:
I removed the engine bay cooling fan, only 6 10mm bolts, it opened up the top of the cam cover for access from above, not sure if it is necessary
disconnect oil pressure sender - front top of valve cover, easily removed from above once engine bay fan is removed
Bank 2 driver side:
The power steering line is right in the way of cylinder 4 and 5 cam cover area. I took off the bracket at the variocam solenoid and disconnected the bracket under the A/C compressor to let it move a bit more. I considered taking that line out but ended up just fighting with it the whole time, I think a stand-off in the end.
Removing the chain tensioner which faces up, under the A/C compressor was easy with a long 3/8" ratchet and the 32mm socket listed in the parts list. My ratchet is a GearWrench 81210P which has "120 positions providing a 3° swing arc so you can turn fasteners in tighter confines", this was useful, I may have had only 2 or three clicks to work with in the tight space. Getting the tensioner back in was a challenge as it is spring loaded, you have to press hard while turning, waiting to catch threads. I ended up stacking washers inside the socket so the pressure from above was transmitted to the tensioner, then reaching my other arm around top and threading a big screwdriver through the intake manifold and pushing on the back of the ratchet with the screwdriver as I turned the tensioner with the ratchet, it worked.
Removing/replacing scavenger oil pumps:
All of the write-ups emphasize "mark oil pump cover" as they have to go back in the same way they came out, I did so and the marks all came off when I cleaned the oil pumps! For that reason I recommend scoring them instead. Mine were very tight! I there are bosses to pry on, I did so gently, keeping it as straight as possible, and they succumbed.
Putting them back in was at first challenging, then easy, I used M6-1.0 x 30mm bolts into all four holes to line them up, then once the pump was just starting I used a borescope which just barely fit into the opening to see if the tab on the pump was lining up with the socket on the cam sprocket. It wasn't so I snuck a pick in to turn the oil pump tab until it lined up and slowly pressed the pump in by using the four bolts, watching the tab for alignment. Once it cleared the insertion point of the tab I kept going, I could feel when the bolts turned easily the pump was lined up well, once they had some resistance I moved to another bolt, back and forth, until it slipped in.
Removing cams:
Once the crossbars are in you can remove the holder at the end of the cams. I really like compressing the actuator with the cams in the engine, Jake Raby does it this way, not all of the videos did so. I just compressed it using the left hand threaded rod until the chain had a little play. Once the cam caps are off the intake and exhaust cam and the long actuator bolts are out I took off the hold down bars and put back in the hold down bolts without the bars, just in the holes below the cams, to create a shelf to hold the cams in place so the whole apparatus didn't fall freely. Those bolts help to stabilize the cams for replacement also. None of my lifters fell out but they were close, I recommend once the cams are out and on the bench put some assembly grease on the lifters to glue them in so they don't fall out later.
I did ziptie camshaft sprocket to the big chain once the sprocket is off the camshaft, not sure if that is necessary but it made me feel good.
Replace Cam Pads:
The more you compress the actuator the easier it is to remove the actuator/cam pads, however I don't know how far you can safely compress it so I just did it until I got enough slack in the chain where I could get it off. I don't recommend zip-ties, they get in the way and break and offer you no adjustability. There are three keys that make getting the actuator out and back in very easy. First off I used the cam hold down bars under the cams as they were on the bench to keep them level, basically in their natural position. Then I fiddled with the sprockets, they can move up and down along the actuator, as well the actuator piston can move up and down. Using these two movements I pushed the actuator piston down and freed the chain from the top pad, tipping the actuator out away from the sprockets, then pushed the piston up and wriggled the actuator diagonally out and up, freeing it from the lower chain. Then put on the new pads and reverse this sequence to get the assembly back in.
Once the new cam pads are installed, new chain installed properly, I loosed the actuator compression rod so the pads were held in there more snugly before I moved the assembly to the car. I didn't want the whole assembly to fall apart as I put it back in. Also the dots on the cams and the marked links on the chain are hard to see once the cams are back in the car so put white paint pen marks on the other side of the chain and cams, opposite of the dots, so I could see that the timing was still correct after install.
Linear Mode
