How to Degree a Cam: What is Degreeing a Camshaft?
What is Degreeing a Camshaft?
|00:00||- One of the key aspects of building a performance engine is to ensure that the valve opening and closing events are occurring at the correct point in the engine cycle.|
|00:09||This is essential, not only to engine performance but also to engine reliability.|
|00:14||The process of correctly adjusting these valve timing events is called degreeing the camshaft or alternatively dialling in the cam.|
|00:24||As with many aspects of engine building, there's a lot of misinformation in the industry when it comes to degreeing cams.|
|00:31||Many novice engine builders believe that degreeing the cams just means setting the cam gear or cam gears at specific positions such as plus two or minus two degrees for example and you'll find this sort of advice on many enthusiast forums when you're researching popular cam options on a certain engine.|
|00:51||The problem with this sort of information is that there are too many assumptions made that can affect the actual valve timing events.|
|01:00||For example, this relies on the accuracy of the timing marks on your vernier adjustable cam pulley as well as the accuracy or the key way or dowel in the camshaft.|
|01:10||In an overhead cam engine, decking the engine block or the cylinder head will also have the effect of retarding the valve timing events, so you can see that for a performance engine, we can't rely on this sort of information to help us.|
|01:25||The only accurate way to set the camshaft position or degree the cam is to physically measure the valve opening with relation to the crankshaft rotation.|
|01:35||This allows us to directly measure and confirm the exact point in the engine cycle where the intake and the exhaust valves open and close, as well as to make adjustments to ensure that these match the cam manufacturer's specifications.|