How to Set Cam Timing on 996

ok, i goofed. i ran into a bit of trouble, and after an IMS bearing retrofit & chromoly oil pump drive installation, my cam timing appears to be a bit off. i need to re-time the cams, and i don't have the tools. here is my plan; if this will not work, i'd love to know why! 1. lock motor to TDC (notch on end of bank 1-3 faces outward) 2. remove bank 1 oil scavenge pump 3. loosen sprocket bolts 4. rotate exhaust cam so notches are parallel to edge of head 5. tighten sprocket bolts 6. re-install scavenge pump 7. rotate engine 360 and lock crank (notch on bank 2 faces inward) 8. remove scavenge pump & loosen bolts 9. index exhaust cam to head just like bank 1 10. button everything back up. the special tool (9612) doesn't look like it does anything but rotate the exhaust cam so the notches are parallel to the head. am i wrong? finally, if i do wind up buying the tools, will the Sir Tools P253 SET the timing, or just lock it? i ask because it doesn't have a sword bolt like the porsche 9612. thanks for the help.

the tool wont work without removing the valve cover - 3.6 motor I assume? I gotta think about this... you want to rotate the cams with the motor pinned and the sproket loose and hope to hit the timing right... right

actually, this is a 3.4L without variocam plus. why won't the tool work with the valve cover on?

i just checked the factory shop manual. 'fine tuning' of the cam is done with the valve cover on.

On a 5 chain not sure right now, have to dig deep in the memory.

What you are proposing can be done. For sure the timing tool fits with the cam covers in place, and yes the cam slot is parallel to the head. I'm pretty sure you can access all the sprocket bolts with the scavenger pump removed. I beleive an 8mm bolt will work as a crank lock. Cam position is much easier to adjust with the cam covers off. The cam can be turned with a 22mm wrench, which makes it much easier to line up. If you choose to remove the cam covers, you will need tool P255 (Sir Tools, above pic) to hold the cams, as the cam cover is half the cam bearing journal. Once the cam cover is off, you need a pair of P256 (Sir Tools, above pic) to be able to hold the cam while you rotate the engine and make the adjustments. The Sir Tools kit is a good value and makes the job pretty easy. BUT why is the timing off? It is unlikely the chain jumped a tooth ... at least not on a 5 chain engine. Did you not have tension on the chains when you tightened the sprocket? Or maybe you turned the engine backwards just a little? Chain tensioners only work properly when there is oil pressure, so hard to adjust properly without oil pressure. The factory tool that replaces the chain tensioner for this proceedure makes it much easier ... and less risky. You probably need to understand why the engine is now out of time before you tackle retiming it ... bent valves are expensive. Also, be careful with the cam cover sealant on assembly ... to much in the wrong place and the green plugs pop out.

The technique you will have to use will be a little different than you have described. Basically you are going to have to line up the cams visually with the crank at TDC. I did not have the tool and you can do this without it. First a little background. The ZDmax/SIR tool is a little different than the OEM tool. The OEM tool locks into the intake cam access hole, not the cam itself, and them fits into the grooves on the exhaust cams and allows you to rotate the cams into position (assumes that they are relatively close to the correct position. So you lock the engine at TDC, fit the tool, loosen the sprocket and rotate the cam to the correct position. then you tighten the sprocket bolts to set the position of the cams. This is done on one side, the the crank is rotated 360 degrees and the other side is done. With the ZDmax/SIR tool it just locks in the cams with the grooves straight up and down so you have to rotate the crank until the grooves are straight, install the tool, them loosen the bolts on the sprocket, move the crank to TDC and tighten the sprocket bolts. Then do the other side. First, how far off are you? If you are fairly close my technique will work. You can't really lock the crank at TDC and then loosen the sprocket bolts and turn the cams as with the valve springs, etc. it is hard to rotate the cams, lots of pressure. When I had my cover off I used a pair of vice grips (kind of crude) on a non-critical part of the cam to rotate it close to position, but this is not possible with the covers on. I even tried to make a tool by modifying a socket to fit into the grooves on the end of the exhaust cam, but even with this and a socket wrench it was not possible to keep enough pressure on the socket to keep it in the grooves and rotate the cam. With the cam cover on and the cams close to the correct position here is the technique that I used. Choose which side you want to do first and get the crank at TDC with the cams on that side close to the correct position. Use a socket on the pulley to rotate the crank ( this is how I did it although Porsche makes a tool that fits into the pulley to rotate the crank). Then rotate the crank slightly to get the groove straight up and down, the crank may not be at TDC. (As an aside, I saw one article that said to never rotate the crank in reverse, but I can't understand why this would damage anything and here we are talking about only a few degrees of rotation.) It can be hard to make sure the grooves are lined up perfectly straight up and down, use a straight edge and the joint between the head and the cam cover as a guide. Once the cam is set loosen the bolts on the sprocket, then rotate the crank to TDC, should only be a few degrees, lock the crank at TDC. Hopefully the cams have not moved. Now tighten the sprocket bolts. I tightened two of them, then put loctite on the other two and tightened them to torque, the loosened the first two and put loctite on them. Now that side should be set. Rotate the crank 360 degrees and use the same technique on the other side. This should get them about as close as you can without the special tool. You need to be fairly precise as 1 degree at the cam is the equivalent of 2 degrees at the crank. Sorry if this write-up is a little disjointed but it is late and I have cut and pasted it from an email I sent to another owner. Let me know if you have any questions. By the way, if you are not going to remove the cam covers you do not need to buy all the tools in the SIR set, which is very expensive, you only need the tool at the top left of the picture. You can use a torx of the proper diameter to lock the crank. The other tools shown are to hold the cams when removing the cover and when removing the cams.

thanks, guys. the timing is off because i had an issue doing an IMS bearing retrofit & oil pump drive installation. i had the tensioners out to do the IMS bearing. i replaced it, & all was well. i then pulled the oil pump, went to look for my new oil pump drive, and it wasn't in the box! i put the tensioners back in w/ the oil pump off. when the new oil pump drive arrived, i pulled the tensioners, but the end of the IMS wouldn't center. somehow, there was enough slack in the chain that when i put the tensioner back in, the chain was between teeth on the sprocket. i wiggled the crank a little to try to get it to settle. it did, but it settled one tooth off..... thanks for the replies.

Oh! I'm betting there was a lot of language when that happened. 50/50 chance and it goes the wrong way. Good luck with the repair. What a PITA.

yea, my point to is the cams are too hard to rotate with them in place just by using the end notch (plus room is limited. you have to make sure the tensioners are out also (right?) to rotate them - I dont think you can loosen the sproket with the tensioner in.? chances are good only one side is off right? the 4-6 bank is fed from the oil pimp side of the IMS so that is your side that slipped.. the IMS Bearing /seal should have held the 1-3 chain in place.. just a guess but check both

It is not the chain tensioners that make the cams hard to rotate, it is the valve springs, etc. When the cam sprocket bolts are loosened, so the tensioners are not a factor, the cams are still tough to rotate. You can definitely rotate the cams with the tensioners in. This is the method I used when I reinstalled my cams and engine. Now have over 8,000 miles since the fix on my engine and it is running strong.

both sides look off to me, but i checked their index prior to any work & they were already off a tad. Raby hinted they may have been set improperly from the factory. my bet is that the chain stretched a bit over time. either way, i plan to set both. you're right that you can't fully remove the cam sprocket with the tensioners in place. however, the tensioners DO need to be in place for the timing to be set properly (according to factory manual).

There is also the variable of the chain tensioners. Porsche makes a set of "pre-tensioners" that go in where the tensioners are and then apply a specified amount of tension to the chains. A set costs about about $500 or $900, I forget. They have them at Baum Tools. I looked at them but the guys at Baum said they don't sell that many of them, most techs just use the standard/real tensioners. Jake Raby once also recommended that I just pump up the tensioners with heavy weight oil (put them in a bath of oil and compress them a few times) and use them. But the use of the tensioners rather than the pre-tensioners could account for a small variation, should not be more than a degree or two.

I do not favor the use of the Porsche pre-tensioners during this process.. Especially since tensioners have changed and been revised over time. I use the engine's tensioners when setting cam timing, its been the only way I haven't seen deviations in timing after the engine ran for a thousand miles or so after the process was carried out. Most engines on the road could stand a timing adjustment, especially after 50K. The bank 4-6 IMS sprocket has a tendency to slip over time, which can create deviations that hurt fiel economy, yet generally don't through a code.. They result in a higher rough running value and I can generally note these from just sitting in the car while its idling..

thanks, jake. i appreciate the input. what's your thought on locking the cam / rotating the crank versus locking the crank / rotating the cam?

Here is a link to Baum Tools pdf of the timing tools they sell. http://www.baumtools.com/pdf/porsche_timing_tools.pdf If you look at the Camshaft lock #9612, it is essentially the same as the Porsche tool. It bolts to the head with the center red ****, then it fits into the exhaust cam and it held in the grooves with the red **** on the right. Then you rotate the arm until the black piece on the left fits into the opening on the head/cam cover at the intake cam. So with this tool you can lock the crank at TDC, loosen the bolts on the cam sprocket, and then rotate the cam to the correct position, then tighten the bolts on the sprocket. With the tool in the set shown in #1 the cams must be in the correct position for the tool to fit, all the parts of the tool are "stationary" so you cannot rotate the cam with the tool. Thus with this tool you must get the cams to the correct position, install the tool, then loosen the bolts on the sprocket, move the crank to TDC, then tighten the bolts on the sprocket. No other way to do it that I know of. This tool goes for about $216, the Baum tool is more like $400.

I always rotate the crank.. Mush less chance for issues that way.

Quotes source post: 7947062

do you always rotate it forward, or do you sometimes rotate it backward a few degrees to reach TDC? my concern is that if i lock the cam & rotate the motor backward a tad, i'll introduce some slack in the chains & the timing will be set improperly.

Quotes source post: 7942352

When you R&R the pump drive, did you just have to relieve the tension on the chains and shafts by removing the three tensioners? I'm a little wary now of doing this considering yours jumped a tooth... but I think I would feel better about this if I have the engine apart (aside from cracking the case) with the cams removed. OP or Anyone else here have some guidance or experience? I am considering R&R the oil pump drive when I have the cam's out to replace some noisy worn lifters with 72k miles along with variocam pads and small chains on my 1999 3.4L. Thanks.

Quotes source post: 8565001

I had other circumstances that caused the issue. The job is straightforward; just be sure to pull the tensioners BEFORE you pull the oil pump. Since you'll have the cams out, you'll need to re-Time anyway. Where are you getting your lifters? Replacing all, or just some?

I'm still shopping around for lifters, but the going rate seems to be around $18 for the BMW P/N. If I have success I'll share it here. And yes I think I'll be replacing all, especially after reading about how it takes a trained eye to determine how much usability is left in them. Yes I certainly plan to do the driver once I have the cams out... now whether I have both sides off or just one bank at a time - I'm guessing as long as all of the tensioners are out, it should be smooth. There's also a few pix of the pump rebuild from Glen? @ 986fix.com http://www.986fix.com/photos.php?view=thumbnailList&category=14

Quotes source post: 7946672

Can you detect this slight timing slip in the drivers seat as a very slight occasional random wobble - perhaps every 5-15 seconds, not like a misfire, but more like the engine stumbles ever so slightly and then it corrects (rpm doesn't change, just the slight little rumble/wobble). And while it seems to disappear and completely smooth out above about 1000 rpm (at least in my car it is actually very slightly detectable even above 1000 rpm - holding my breath and concentrating to feel it, or pretty much sitting on the door sill). I broke out the Durametric yesterday and logged some data after the car was warmed up, and my engine has 72k miles on the clock. For what it's worth, I swapped the (20k old) coil packs and (10k old) plugs from bank 1 to bank 2 and still feel a little tiny wobble every so often at idle. Camshaft deviation is constant -3 on bank 1 and 0 on bank 2. T/B is clean, AOS replaced, LN IMS retrofitted, fuel additive, no vacuum leaks. Also read it could be chain stretch... but after reading this I bet the timing is not 100%???

What's the y axis here?

Good question. If I understand correctly?, basically it is a value assigned by the DME based on a number of factors, which are basically summarized by the following??? Proper engine timing would result in near 0 value where improper timing/detonation would result in a value greater than 0, and at some point as determined by the DME, a rough running value observed greater than the threshold would result in a CEL (and other gremlins). However, I am certainly not an expert... just an enthusiast. It would be great if an expert could chime in. The 996 WSM for a 3.4L states the following regarding warm idle rough running acceptable values. Rough running threshold should be at 9.2. Deviation +/- 1.3 (1/s squared) Rough running should be at 0. Deviation +/- 1.5 (1/s squared) I suppose the whole air/fuel/spark/compression/vacuum formula probably also contributes here... Google "rough running value" "Method for detecting combustion misfires and cylinder equalization in internal combustion engines with knock control. The invention relates to a method for combustion misfire detection and cylinder equalization in a multi-cylinder internal combustion engine having knock control. In the method, rough-running values are individually determined for each cylinder by measuring segment times with each crankshaft rotation. The segment times include the times corresponding to the piston movement of each cylinder to be measured in which the crankshaft passes through a corresponding circular-segment angular region. Thereafter, the determined rough-running values are compared to a threshold value in a desired value comparison and, on the basis of the deviation between the determined rough-running values and the desired value, cylinder-individual equalization factors (that is, correction factors) are computed in an evaluation unit for the change of injection times or ignition time points of the individual cylinders. It is provided that the computed equalization factors (GL1) for the change of injection times or the ignition time points or the charge serve as the basis for the determination of a rough-running increase value (LUTcorrected) effected by the change and that, with the determined rough-running increase value (LUTcorrected), a computation of a corrected rough-running value (dLUT) takes place. The corrected rough-running value (dLUT) is utilized for the computation of the final equalization factor (GL2) for influencing injection times or ignition time points or the charge."

Have been searching far and wide for step by step instruction for timing on a 5 chain. Completed IMS and RMS replacement on 99 boxster base.I have To pull my cam cover to replace a solenoid and want to check and reset timing if needed.Did your step by step method work.... I'll be using the 9612 tool the P253tool didn't work for me....it had issues. Please let me know if you had any success. Yours is the 1st simple list that makes everything clear. Thanks in advance. V

Quotes source post: 15396557

Not sure if you realize you opened a 8 year old post.