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Showing results for tags '986 deviation'.
Here is a Camshaft Deviation situation with a much tighter focus than normal.I have also included the best links I found to help others who find this through Search.This is a 5 chain engine.2001.Boxster S. The engine is just rebuilt by me. It runs wonderfully well with no Fault Codes, none. Great oil pressure.compression even on all cylinders. New chains,but original tensioners,new wear pads,new IMSB, IMS shaft pinned. But Bank 1 Deviation is negative 8 degrees. Bank 2 is much less than 1 degree negative. Spec is max 6 degrees +/-. Deviation is rock solid on both Banks throughout the rev. range(except for normal Variocam change). No Pending or Active Codes. I recently had Bank 1 Cam Cover and Cams off to rectify an obscure VarioCam issue (Thank you PorscheTech3!). I re-timed the Cam on Bank 1 using the Baum Tools. The tools are excellent but clearly(?) need a degree of finesse in use that I was unaware of. 8 degrees CRK per Durametric is only 4 degrees at the cam so it is impossible to do a visual check of the slots in the Camshafts to confirm if this is a static cam timing issue or a Camshaft system component failure. So I am resigned to re-do the timing but need reassurance on the precise technique to use before I R&R the Cam Cover again. Cam Timing Details are in the links at the end of this Post. Here is the tentative plan that I hope others will be able to correct : Follow Procedure in links below to lock the Cam with the Baum Tools close to TDC. To get perfect Cam timing, I'll need to very slowly rotate the Crankshaft forward toward TDC. Only when the tools fit perfectly will I lock the Baum Cam Timing tool. Then I'll try to insert the TDC Crankshaft Locking Pin. Knowing that Bank 1 is excessively retarded 4 degrees(cam), I should expect that the Crankshaft Locking Pin will not slide in easily when the Cams are perfectly timed. At this stage I should loosen all the Camshaft Sprocket bolts. But not remove the (old) Chain Tensioner - right ? Then the Crankshaft should need rotating 'forward' 8 degrees until the Crankshaft Locking Pin slides in easily.Then tighten the Camshaft Sprocket bolts. Then rotate many times and re-check. The Bank 1 Timing Chain Tensioner is still very powerful and seems as 'strong' as Bank 2. When I refitted Bank 1 Tensioner last time, it required serious muscle to force it upward while delicately engaging the threads. So I assume it is functioning adequately and is not the cause of the out-of-range Camshaft Deviation .I am assuming it is original(90,000 miles). What other components should be checked ? I did check the Camshaft Position Sensor for correct fitment and the Reluctor ring for damage during the VarioCam repair. https://rennlist.com/forums/996-forum/594122-how-to-set-cam-timing-on-996-a.html see Post #7 http://www.pelicanparts.com/techarticles/Boxster_Tech/16-ENGINE-Camshaft_Swap_and_Chain_Tensioner/Gp1800.pdf Good dwg and description of mechanism and parts. Please add your best links if you have any in your replies so that this may help others with the Deviation issue? And thanks in advance for any suggestions and corrections.