How to Degree a Cam: The 6 Step Process
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The 6 Step Process
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| 00:01 | - At this point, you should have a good understanding of the operation of the camshaft and you should understand what we're actually trying to achieve when it comes to adjusting our cam timing. |
| 00:10 | In this module, we're going to cover the actual procedure that you'll need to go through in order to correctly degree your cam or cams. |
| 00:18 | In order to give you a solid and easy to follow procedure that you can apply to any engine, we've broken the process down into the HPA 6 step process. |
| 00:28 | This gives you a process that you can use on any engine and it ensures that you don't overlook any critical steps. |
| 00:35 | I'm going to cover each of the steps now but you will also be able to watch the process being applied from start to finish on a range of different engines in our library of worked examples. |
| 00:46 | The very first step of our process is to set the base cam timing of the engine by following the workshop manual. |
| 00:53 | At this point we're really ignoring the fact that we have aftermarket cams or an adjustable cam gear, and we're treating the engine exactly as if we're assembling it with all stock components. |
| 01:05 | The process will vary from engine to engine and I always start by locating the factory workshop manual and following their specific step by step procedure. |
| 01:15 | This will involve aligning the crankshaft and the camshaft pulley or pulleys to align with specific match marks on the cylinder head and the engine block prior to fitting the cam belt or cam chain and tensioner system. |
| 01:29 | If you're using a two piece vernier adjustable cam gear, you always want to start by ensuring that this is adjusted to the zero point as well as making sure that the locking bolts are tightened. |
| 01:40 | Once we have our cam or cams timed using the factory procedure, we can move on to our second step which is to fit our degree wheel and find true TDC. |
| 01:51 | While the engine is probably going to have some kind of TDC marker on the pulleys already, this is not going to be accurate enough for our requirements and you'll often find that the factory marks are out by several degrees. |
| 02:04 | We cover this process in detail in the practical skills section of the course, so you can refer here for a more detailed approach to doing this. |
| 02:13 | The third step of the process is to fit our dial gauge. |
| 02:17 | We're going to be starting with our dial gauge located on the intake of number one cylinder and we need to decide whether we're locating the dial gauge on the valve spring retainer or lifter bucket or alternatively in a push rod engine, we may be locating the dial gauge directly onto the end of the push rod. |
| 02:34 | We'll discuss these options in more detail shortly, and again this process is detailed in the practical skills section of the course, so you can refer there for more information on how it's done. |
| 02:46 | Once we have our dial gauge installed, we also need to zero the dial gauge so that it's reading zero lift when we're running on the base circle of the cam and the valves are closed. |
| 02:57 | The fourth step is to measure our intake cam timing as the cam is installed right now. |
| 03:03 | Even when you're familiar with cam operation and degreeing cams. |
| 03:07 | It's still easy to get confused here and I always recommend drawing out the valve opening versus engine cycle graph that we looked at in the camshaft fundamentals section, before starting. |
| 03:18 | This helps because we can easily reference where in the engine cycle the valves are opening and closing. |
| 03:25 | Once we know where the valve timing events are currently occurring, we can compare these to our cam specification card and either advance or retard the cam timing as required to achieve the manufacturer's recommendation. |
| 03:38 | You can refer to the practical skills section of the course to see how this particular step should be completed. |
| 03:45 | If we're dealing with a double overhead cam engine, then the fifth step of the process is to perform the same measurement and adjustment process on the exhaust cam. |
| 03:55 | Of course this will require the dial gauge to be moved from the intake to the exhaust cam, but once the dial gauge is correctly fitted, the process is identical to what we've just completed on the intake cam. |
| 04:07 | If you're dealing with a single cam engine then there's no need strictly to check the exhaust valve timing since it isn't adjustable with respect to the intake timing. |
| 04:18 | And if your inlet valve timing events are correct, then by definition, the exhaust should be too. |
| 04:24 | With this in mind, we can skip the fifth step, however it can provide a nice sanity check to double check your cam degreeing and ensure that the valve timing events for both the intake and the exhaust match the manufacturer's recommendations. |
| 04:38 | The sixth and final step is to make sure that any of the bolts for the cam gears that you've loosened for the purposes of adjusting the cam timing, are correctly tightened. |
| 04:48 | Failing to do this can result in the cam timing moving in operation which can cause serious engine damage. |
| 04:55 | In order to do this, I use a product such as Loctite 242 which prevents loosening due to vibration but still allows the bolt to be loosened with relative ease with hand tools during dissasembly. |
| 05:08 | At this point, your cam degreeing is complete and you can remove the dial gauge and degree wheel and complete the final assembly of your engine, ready to start it for the very first time. |
| 05:19 | What we've covered here is a relatively generic process which can be adapted to different engines. |
| 05:26 | However in the following modules we'll deal with some of the considerations you may need to keep in mind for certain engines. |
