M96 3-chain engine stuck

I have a 3-chain M96 engine on my workbench trying to replace tensioners and chain guides. I started with bank 2 (on the overlap of cylinder #4). I finished that side, replaced the cover checked that the timing was perfect. Rotated the crank 360 degrees, smooth and easy, and locked the #1 cylinder at TDC on overlap stroke. Once I replaced all of the chain guides and tensioners on bank 1, I installed a new intake cam bolt in the required two stages. When I was angle torquing the bolt to the 110 additional degrees, the aluminum cam slot-holding tool (yes, I made it myself) bent under pressure from the bolt torque. That in turn rotated the cam backwards. I did not notice this as I was on the opposite end torquing with all my strength. And I had a steel Allen wrench in the TDC hole on the crank pulley. When I removed the wrench and rotated the crank about 10-15 degrees I heard a pop and saw that I was just coming back to TDC! Now the crank is stuck -- it won't turn any farther in the clockwise direction. So, yesterday I removed both cams again to let the valves close in case a valve was out of time and contacting a piston. No luck -- the engine is still stuck, but it does rotate backwards a few degrees (I know... never do this, but I had to determine if a piston was obstructed on the way up). Any thoughts before I remove the bank 1 head? I removed each lifter one at a time and saw that the valve stems are all still visible in the same relative position above the retainers. Perhaps the bank 2 chain or the IMS chain broke or slipped and jammed. I'll remove the bank 2 cover today. Has this happened to anyone here? Thanks!

I'm not sure which video it was, but Man in a Garage had a stuck engine while he was building it and the center chain had come off and jammed. He had to crack the block to free it up and once it fell into place it was fine. https://www.youtube.com/channel/UCEF...jFAVqPA/videos It took me a while to warm up to this youtuber, but once you get what he is trying to do he actually does it very well. There is a ton of excellent information here and he has taught me a ton about this engine. maybe one of these videos can help? Best,

Thank you for that link! I would never have run across it on my own. I'll check it out today.

@iwanta996 , you are going to have to pull both heads at a minimum. At that point you may bet lucky and see the issue.

I have done some home made tools, but when it comes to cam holding tools, I just buy the aftermarket but professional versions. Even if it prevents one little mishap, it is worth its price. I just paid $400 for a set of BMW cam timing tools for the 2003 540i in my shop last week. Well worth the money. For the 996/997, I have the Sirtools version. Used it many times, and well worth its prices.

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Generally any cam holding tools are not supposed to be used to hold the cams for torquing. All cams I have ever seen have a hex section that can be held with an open end wrench. Do the M96 cams not have this?

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They do, it fits a 32mm wrench (I think).

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The cam holding tool is holding the lock nut tight and preventing the cam from turning while tightening the main center bolt to intake cam. The tool is designed where one end is on the locking nut and the other end rests in the scavenger pump housing of the case to hold it tight. it's a pretty high torque so I doubt you could just hold a wrench on that lock nut by hand to prevent it from turning while you torque.

See this vid: HOW TO: PORSCHE 911 Engine Cam Timing - YouTube At about 10:xx minute mark, he uses a 24mm wrench to turn the cam shaft using a couple of flat spots on the cam, right at about the middle of the shafts where the number 5 spark plug is. You can use that to lock or hold the cam shafts while torquing the end bolt. You need a long 24mm wrench, with a long cheater pipe to have enough leverage. Maybe 2 persons is better than one. I just went through the same thing last week on a 540i BMW. It needed a 32mm wrench (with the box end cut off, and a 30 inch cheater pipe) to counter hold, while I torque the T-55 bolt at the end with a 24 inch torque wrench set for left handed thread. the cam shafts were positioned with the holding-positioning tool, and the counter-force was provided by the 32mm wrench.

Jake Raby goes over the timing procedures for these engines in the Focus On: M9X Engine Assembly video series - both for the 3 chain and 5 chain M9X engines. Not only does he cover every step with the upmost detail and precision, he also demonstrates the correct tools for the job. IMHO, every shop that works on Porsche M96 or M97 engines, should have this training video series and supplemental workbook. https://www.theknowledgegruppe.com/p...ideos-bundles/

Huge mistake was made using the cam timing tool to hold the cam for the torquing procedure of a 3 chain engine. One of the biggest mistakes that can be made. 10 years ago I caught one employee doing this, and fired him on the spot. Your saving grace on the camshaft may be that the tool did bend, else the camshaft can snap. We have had that occur in a hands- on class when I allowed my attendees to move forward doing this procedure improperly, to teach them a lesson the real way. My video specifically goes over this procedure, so you don't screw yourself. Yes, I made this mistake, but that was before the manuals for these engines were even released, and I learned 100% of what I know from mistakes made, and remedied. The pop could have been many things. You have a mechanical collision, and it may even be on the opposite side of the engine.

� I allowed my attendees to move forward doing this procedure improperly, to teach them a lesson the real way.� It�s painful, but it�s the best way to learn. You can bet they�ll never forget that lesson 👍

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It's the only way to learn. Nothing else is painful enough. I teach my daughter the same way, I watch her make the mistake, and let her learn the agony of defeat. A few months ago I watched her cross- thread a bolt, and kept watching her till she snapped it off. Then she had to saw it off, center punch it, and drill it out, then tap it. At age 10 she can do more than most modern day men living in a world of toxic masculinity BS. Some say this style is barbaric today.

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This is the tool you need to tighten that bolt.

For some reason I'm not getting notices that I have responses to this thread, or I would have thanked you all earlier for your wise advice. And I agree, Failure is a tough teacher. I've gotten to know him on this project very well. Yelcab, thanks for the link to the cam timing video. I have watched several of those videos now and have learned a lot. And, I now have the proper tools, made of steel, not aluminum. My confusion about the two-piece tool is that the Porsche manual for the 3-chain engine states that after the initial 50 lbs. of torque, the mechanic must remove the tool before adding the 110 addition degrees of angle torque. The manual did not mention to counter hold the intake cam with the big crescent wrench while angle torquing the intake cam bolt, but it makes sense now. I have now removed the cam covers and all four cams again. Now the crank is moving freely! I inspected all of the valve stem positions and they all look to be undisturbed. My first mistake was finishing the cam timing before reinstalling the oil pump and cover. That led to the drive end of the intermediate shaft becoming off-center and very tight against the opening. I thought it would move to the center when I rotated the shaft, but it went right and then got stuck. So, one of the chains likely jumped and then became too tight to move as well. I also found that both cam oiling sleeves had been installed from one to three times in the wrong position by previous mechanics. There were dents from the back pin as it pressed into the soft aluminum sleeve when the sprocket bearing caps were torqued. So, I have ordered two more of those. No we are waiting on the winter storms to clear up enough for the deliveries to resume to my local dealer. Thanks again for guiding a "newbie" through the steps. I have rebuilt an AMC 327 before, but it was child's play compared to the Porsche engines. That old AMC engine is still purring along after 20+ years since the rebuild.

Another dilemma. This car is new to me. I found that a previous "mechanic" mis-aligned the cam bearing sleeve near the intake sprocket, which caused the camshaft to sit slightly crooked (for a short time) and that caused the typical DTCs when driven by the PO. That led to one of the two camshaft rings to break. I bought a new one and carefully fit it in place. Now I cannot slide my new big aluminum bearing sleeve over the rings. I assume there is a tool, similar to piston ring compressor, but I cannot find one after extensive searching. Does anyone have a DIY method for squeezing the ring while sliding the bearing sleeve over it? I can upload photos if that helps.

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For god's sake, show a picture.

Those rings compress with your fingers as you work the sleeve over the rings. As b3freak recommended, I would highly suggest that you buy the assembly video, or at least the videos showing assembly of the camshaft and components and timing process. It is by far the most comprehensive assembly video (and only professional one that I know of) for building this engine and the step that you are trying to complete is one that gets screwed up often because the manuals are hard to follow or leave steps out. I was under the impression that those rings are not easily replaceable (I remember Jake talking about these replacement of these rings i'm pretty sure but I know he covers how to clean and reinstall that sleeve as part of the cam assembly).

I replaced those rings on my Turbo. They are similar for the M96 engine. Thread here -> https://rennlist.com/forums/996-turb...-annoying.html The upshot is just compress them with your fingers and slip the housing over the nose of the camshaft. I found it easier to do this with the cams out of the engine; I don't know if that is possible on an M96 as I haven't had one apart.

Thanks for the quick response Yelcab. Here are two photos. The first one is the damaged bank one sleeve. Bank two had only one impression indicating a mis-alignment. While typing this I saw the other two replies, so thanks for your quick responses. I tried to do it with my fingers but I could not hold the ring and push the sleeve on. I thought about how a ring compressor works and decided to try using my channel locks with duck tape on the jaws to compress the ring while pushing/turning the sleeve. That worked perfectly, with no damage to the shaft or rings. I'll be sure to post images first from now on to help with context. Bearing sleeve with THREE failed installations (not by me) to align the blind pin and corresponding hole. New sleeve in position. I am ready to set the timing now. I will be certain that the number one piston is on the overlap stroke at the TDC mark, then proceed per the Bentley instructions. I'm still not sure of the best method to counter-hold the intake camshaft when I angle torque the bolt. There are two cast nodes in the middle, but my 24mm wrench will not quite fit over them. Maybe I can use an adjustable wrench. Jake advised against using the flat locking tool to hold the shafts, and I respect his experience and that of others on this forum. The "Man in a Garage" video used the two piece swivel tool to hold the cams on his 5-chain, and I will gladly buy one if it will fit on a three chain cam setup. I have the intake bolt tool, but Bentley says to remove it for angle torquing. Thanks as always for your help.

See my post above. That is the tool you need. You also need the two bridges to hold the camshafts down and help install the camshafts without breaking them. You can see the tools on my build thread.

Jake asked me to extract this clip from the Focus On: M9X Engine Assembly. This is from Stage 14 of the series where he covers installation of the plain bearing on intake camshafts. Enjoy! And again, I encourage everyone that is doing this job to consider purchasing the full M9X assembly training package from The Knowledge Gruppe or other retailers like LN Engineering or Pelican Parts. You Tube

b3freak (and Jake) thanks for that free video clip. I'm going to save up for a set of Jake's videos for sure. It's a miracle this engine didn't seize up from the shoddy work performed right before the PO sold it to me. Adding the black indexing marks to the bearing sleeve is so simple, but genius. I can see now that it is near impossible to confirm that the sleeve has not rotated off of the back pin without those markings. That happened to me before the IMS shaft issue, but I caught it before clamping down the bearing caps. amargari, I purchased the cam holding tools you showed above earlier this week, so I'll use the 2-piece tool (9686) to hold the intake shaft while applying initial torque to the end bolt. Did you leave the tool in place when angle torquing the additional 110 degrees? If not did you counter hold with a 24mm wrench or something else? I'll need to order the cam bars tonight for delivery at the end of this next week. Wished I had done that sooner. Since all four cams are out now, do you recommend completely installing/timing the bank 1 cams, then installing/timing bank 2? Any concern about the bank 2 chain rolling off the front IMS sprocket if those cams are not in place when rotating the engine for bank 2 overlap?

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The bridges are used to hold the camshafts to the head and to help distribute the downward pressure on the cams when installing them. You tighten them along with the caps a little bit at a time on each one bolt to slowly bring the cams in place. You use the tool above that I posted for both stages of tightening the bolt. The original torque amount and the additional 110 degrees. Also, do not have the flat tool installed into the back of the cams while doing this.

Thanks amargari, for your patience and timely advice. I know I can do this now. I'll update you all once the bars get here and I've finished the cam timing.

@iwanta996 , I just went back and rewatched the Jake Raby video on cam timing. I fixed my response above. You use the tool for the initial torque and the second degrees of torque. What through me off is Jake does 3 stages of torque in the video. So use the tool for both steps of torquing. Also, make sure you remove the tool from the end of the cams that keeps the cams from moving.

That's good to know, since I don't have the full video. So, during the final angle torquing is it normal to see some cam rotation? At that point I'll have the exhaust cam bolts torqued and the chain tensioners and chain guides all in place and torqued down per spec.

I am not an expert, but if everything is linked together, some slight movement until the tool fully contacts the bearing surface should be ok as long as both cams move the same amount. I assume that is why Jake teaches to put 3 levels of torque on the intake camshaft bolt. The first level secures the gear to the camshaft and makes sure the cam doesn't move separately from the gear. The next two steps are to make sure it is tightened properly. In the video, he does the first light tightening when the camshafts are locked together. Then the next two stages with the tightening tool and the camshafts no longer locked together with the plate.

That makes sense now that I've tried it and had the flat aluminum tool bend on me during final torque. It's really hard to angle torque all the way through 110 degrees without a pause to reposition the ratchet or breaker bar. After I reach the initial 50Nm mark, I plan to use a white marker to make two dots on the case, one at the 55 degree point and one at the end. My new steel tools are due to arrive tomorrow afternoon, so I'll start tomorrow night. And of course, I have two new intake cam bolts from my local dealer.

Quick update on my progress installing the camshafts. I have read and re-read the recommended installation instructions several times, so I think I'm doing everything right so far. I have the crank in the U6 position, pinned with the short crank tool, and I'm starting with bank one in the overlap position. The intake camshaft is in place with the bearing sleeve indexed to the blind pin in the bearing saddle. I have all three tensioners loose (oil pump is installed and torqued, so no more intermediate shaft moving off to one side). Here's my problem: I cannot get the exhaust camshaft to fit into position. The chain does not have enough slack to allow the sprocket and the big shaft flange to mate up. Have I missed a step? They are close, maybe only 2mm from sliding together. Has anyone tried installing the exhaust first and then the intake? Not sure if that would cause the same issue on the intake cam.

When I did it I did the following: Crank should be locked on OT. That is the teardrop shaped hole. Not U6 Cams should be locked using the tool at the end of the cams Tensioners should not be installed until you are ready to time the cams The chain guide mounted to the camshaft journal caps should not be installed until the chains are on both cams. Remove the exhaust cam pulley, put the chain on the pulley then put the pulley with the chain on the cam. Make sure the 4 mounting holes are centered in the gear slots Reinstall the chain guide mounted to the camshaft journal caps Pump up the IMS tensioner with oil by submerging the tensioner in oil and working the plunger up and down until it is nearly impossible to press down. Install the IMS tensioner. This will be difficult to do. Do the same with with the Bank 1 tensioner as the IMS tensioner If both cams are aligned with the tool, then torque down the exhaust cam gear. Put enough torque on the intake cam to keep the cam in place. This is less than the initial torque amount Take the cam locking tool out of the back of the cams Take the locking tool out of the crank pulley Torque the intake cam bolts using the tool and the two step sequence. Make sure the bank 2 intake cam is not tightened down and the gear can move without moving the camshaft Install the camshaft locking tool for Bank 2 Install the cam 2 exhaust camshaft gear with the chain but no bolts. Rotate the engine once 360 degrees. The chains should move, Bank 1 cams should move, but Bank 2 cams should stay stationary. Lock the crank pulley on OT. This is the teardrop shaped hole Repeat the same steps now as Bank 1 with the tensioner, exhaust cam locking, etc... Once everything is done. Rotate the engine 360 degrees 7 time and verify that the cam tool fits in the bank 1 cams. Rotate another 360 degrees and verify that the cam tool fits in bank 2. If the above is true then your cams should be timed. .

Thanks to you, Amargari, my camshafts are perfectly timed! I followed your method point by bullet point. My only addition to the instructions is that I could not partially tighten down the intake cam bolt without first fitting it with the holding tool, #9685. You no doubt do that, but since this was the first time to do the cam timing I tried to torque it down about 25 Nm with the bare digital torque wrench. The holding nut was out of position in relation to the exhaust recess when I fitted the nut holding tool (#9685). So, I backed that off to zero, since it was well before the bolt started to stretch. I want to strongly advise anyone who attempts this on their own to get the proper tools. I foolishly tried to make my on cam holder (9686, for the ends) but it bent (thanks to Jake for the needed "redirection" and a free video clip). Only by using the proper tools, and reading amargari's detailed notes above (several times) was I able to accomplish this task. I rotated the engine after I was done and both camshafts line up with the tool at their respective overlap stroke, but not on the compression stroke. I did not use the U6 crank position, as amargari recommends. I can tell you all now that it worked perfectly without that, as the lifters were at or near the closed position that I was able to easily insert and align the camshafts. Earlier I had posted that the exhaust shaft sprocket would not fit, but I found out why, and boy am I glad it did not cooperate. The intake sleeve had slipped out of alignment with the pin, even though I had marked it and made certain it was in place. That sleeve and move parallel to the shaft and it can rotate in the bearing saddle. After that I rechecked it two more times as I went along by inserting a small punch into the open hole and gently pressed it up and down to be sure there was no rotation. It pays to double and triple check critical alignment stages as you go. If something seems wrong, then it probably is wrong. After using assembly grease and light oiling in all the critical spots, it's on to installing the valve covers, new AOS, low-temp thermostat, and the dozens of other items required before fitting the engine and transmission back into their home in the engine bay. I won't bore you all with any more progress reports, as it's pretty routine from this point. Thanks for all of your collective advice and patience with a novice Porsche enthusiast.