Figure 1 | | Okay, with the bearing puller broken we now started in on the removal of the camshaft towers. We'll get to the intermediate shaft bearing tomorrow when the bearing puller is shipped next-day air to Callas Rennsport. Using a set of mini pry-bars, or a set of pliers, carefully remove the spark plug tubes from their bore. These are plastic, and have a tendency to get old and brittle. They can also leak - I recommend replacing them if they look really old when you change your spark plugs. | | Large Image | Extra-Large Image |
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Figure 2 | | Remove the rubber cam plugs on the end of the camshafts. These get damaged when you remove them (poke a hole in the center), so be sure that you have new ones on hand ready to install if you are simply replacing your camshafts. | | Large Image | Extra-Large Image |
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Figure 3 | | Here's a handy-dandy camshaft holding tool that the fellows at Callas Rennsport designed to keep the camshafts in place when removing the side cover. The camshaft covers contain the "bearing caps" that hold the camshaft to the heads, so when you remove the covers, the cams will pop out if they are not held in place. I believe this is very similar to the factory tool. | | Large Image | Extra-Large Image |
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Figure 4 | | Here's a side view of the camshaft covers showing all of the little bolts that need to be removed in order to get to the camshafts. | | Large Image | Extra-Large Image |
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Figure 5 | |
Figure 6 | |
Figure 7 | |
Figure 8 | | There's a backing plate that fits around the solenoid that controls the camshaft timing advance. Remove this plate. | | Large Image | Extra-Large Image |
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Figure 9 | | It's always a good idea to mark parts so that you know where they go if you try to put them back together again. Here we have marked the camshaft oil scavenge pump so that we know exactly how to mount it again in the future. Remove these bolts - two of them are attached to the head, and the other two are attached to the camshaft cover. | | Large Image | Extra-Large Image |
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Figure 10 | |
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Figure 12 | | The cover should be able to simply be lifted right off. If you don't have the camshaft holding tool installed, then the cover will be spring-loaded and flip out at you. | | Large Image | Extra-Large Image |
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Figure 13 | |
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Figure 15 | |
Figure 16 | | Here's a neat shot of the camshaft cover removed. The top camshaft is the intake camshaft, the lower one is the exhaust. They are tied together with a small chain that is attached to a tensioner / advance mechanism that slides back and forth and changes the relationship (in degrees) between both camshafts. This device is controlled by the solenoid in the center. | | Large Image | Extra-Large Image |
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Figure 17 | |
Figure 18 | | Here's a close-up shot of the camshaft timing advance mechanism. Note that this engine only has camshaft timing advance - later engines have variable camshaft valve lift as well. | | Large Image | Extra-Large Image |
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Figure 19 | |
Figure 20 | | This photo shows the sprocket that connects to the chain that links to the intermediate shaft. These engines have five separate chains - one that goes from the crankshaft to the intermediate shaft. Two that drive each exhaust camshaft from the intermediate shaft, and two that connect each intake camshaft to the exhaust camshaft. On the new 2009 cars with direct injection, these new engines have had their intermediate shafts completely designed out of the equation (a good thing in my opinion). | | Large Image | Extra-Large Image |
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Figure 21 | | Here's an inside look at the chain tensioner for the chain that connects the intermediate shaft to the exhaust camshaft. You can remove this now from the bottom of the engine case. | | Large Image | Extra-Large Image |
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Figure 22 | |
Figure 23 | | I forget exactly what this photo is supposed to show, but I might have snapped it show how awful the oil was inside of this engine. This is what the oil looks like when you have a significant amount of coolant that gets mixed into it. It becomes very brown and milky, and reminds me of those days when I've accidentally consumed some bad Mexican food! | | Large Image | Extra-Large Image |
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Figure 24 | | This is a special factory tool that the guys at Callas had on the shelf. It attaches to the end of the camshafts and holds one in place while the other is timed. It would be very difficult to properly time and adjust the camshafts without this factory tool. | | Large Image | Extra-Large Image |
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Figure 25 | | Also related to the camshaft timing tool, this pin goes in the front pulley to lock the crankshaft into Top Dead Center (TDC). There is a boss in the case that the pin fits into. | | Large Image | Extra-Large Image |
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Figure 26 | |
Figure 27 | | Here's a photo of one of the two scavenge oil pumps on the workbench. It's quite simple, these oil pumps pickup excess oil from the bottom of the camshaft housings and funnel it to the bottom sump. Porsche wanted to really get away from the use of a dry sump system (used on all the air cooled 911s) because such a system is complicated and expensive. These pumps are an attempt to improve the performance of the wet-sump system. It didn't really work too well, as these engines aren't raced very often. | | Large Image | Extra-Large Image |
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Figure 28 | | Here's the backside of the camshaft housing cover. You can see that the cover has the bearing surfaces embedded into itself. Oil doesn't pass through the metal in this cover, but it's provided to the bearings from the opposite side (note the grooves cut into the bearing surfaces for oil passage). | | Large Image | Extra-Large Image |
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