M96 3-chain engine stuck
#31
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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.
#32
Racer
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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.
#33
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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.
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.
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amargari (02-21-2022)