How to Degree a Cam: Step 1: Set Base Cam Timing
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Step 1: Set Base Cam Timing
04.43
| 00:00 | - The first step of our process is to set the base cam timing. |
| 00:04 | Prior to getting to this point, we've already gone ahead and stripped the front of the engine to gain access to the timing gears and the timing chain. |
| 00:11 | This requires the removal of the radiator and water pump assembly as well as the oil pump which in turn requires the sump to be dropped. |
| 00:19 | We've also removed the rocker gear and push rods to allow us to swap out the existing valve springs for the beehive springs matched to our new cam. |
| 00:28 | At this point, the factory cam can then be removed and the new cam lubricated and slid into place. |
| 00:34 | A small tip while swapping a cam in an LS in place is to use a lifter retaining tool to hold the lifters while the cam is removed and refitted. |
| 00:43 | Failing to do this can result in the lifter dropping which is then a major problem to rectify. |
| 00:49 | We're going to start by fitting the Crow Cams double row crank sprocket to the crankshaft. |
| 00:54 | This is a vernier design with multiple keyway locations. |
| 00:57 | Each keyway is marked so that we can understand how the location we choose will influence the cam timing. |
| 01:04 | For example, we can install the cam at 0° or advance or retard it in 2° increments. |
| 01:10 | What we do need to do is to make sure that we're using the correct mark on the outside of the cam sprocket when aligning this with the cam sprocket mark. |
| 01:19 | The factory crank sprocket only has a single mark for timing the engine, whereas the Crow cam sprocket has the same markings on the outside as it has on the inside keyway locations. |
| 01:30 | We need to use the same mark on the outside of the cam sprocket as we've chosen for the crank keyway as the reference when timing up the cam. |
| 01:38 | For our example we'll start by installing the cam at 0°, this means that we install the sprocket on the crankshaft using the 0° keyway location. |
| 01:48 | When the timing is correct, we'll have a vertical line through the centre of the cam sprocket, down through the timing mark on the cam sprocket, then through the 0 mark on the crank sprocket and then finally through the crankshaft centreline. |
| 02:01 | To do this we want to start with the crankshaft at TDC on number one cylinder which should be where it was left during the cam removal and installation process. |
| 02:11 | We need to make sure that the crank pulleys installed in the correct orientation with the numbers to the front and the chamfer to the rear. |
| 02:18 | With the orientation correct we can then slide the 0 keyway over the key in the crankshaft. |
| 02:24 | This may require a gentle tap with a plastic hammer in order to ensure that the sprocket is properly seated against the crankshaft. |
| 02:32 | Next we can install the chain tensioner. |
| 02:34 | This is a source of debate amongst LS engine builders as there are a couple of tensioner designs and the factory tensioner doesn't really locate perfectly against a double row timing chain. |
| 02:46 | Many people omit the tensioner all together but my preference is to retain the tensioner. |
| 02:51 | In this case we're starting with a brand new tensioner and at this point we're just going to locate it approximately in the right location but we won't' bolt it down as this will make it harder to fit the cam sprocket next. |
| 03:02 | Next we can locate the cam so that the dowel is positioned horizontally at the 3 o'clock position when viewed from the front. |
| 03:09 | This is going to make it easier for us to fit the cam sprocket. |
| 03:13 | Now we can install the thrust washer onto the back of the cam sprocket. |
| 03:17 | It can help to use a couple of dabs of assembly lubricant to help keep the thrust washer seated during the installation process. |
| 03:24 | It's also important to make sure that this is installed with the black face against the block to prevent damage. |
| 03:30 | Next we can fit the chain onto the cam sprocket and then align this over the crank sprocket. |
| 03:36 | This is a bit of an awkward process as we need ensure we've located the cam sprocket and chain so that when it's installed, the timing marks align vertically as previously mentioned. |
| 03:46 | We'll also need to move the tensioner out of the way as we slide the cam sprocket into location. |
| 03:52 | Normally we'd locate the chain onto both sprockets at the same time and slide this onto the crankshaft however with the Crow Cams crank sprocket needing to be tapped into location, this procedure would be difficult to complete easily. |
| 04:05 | Once we've got the cam sprocket fitted onto the dowel for the camshaft, we can now install the bolts for the camshaft and tighten them. |
| 04:12 | There's no need to loctite these at this stage since we're likely to be removing them again to make any timing adjustments. |
| 04:19 | With the cam pulley tightened down, we can now install and tighten the 2 bolts for the chain tensioner and lastly perform a final check of the timing marks. |
| 04:28 | I like to use a steel rule for this as it makes it easier to confirm that the alignment is in fact correct. |
| 04:34 | Providing that our timing marks do align properly, we can pull the pin on the chain tensioner and we're done. |
