How to Degree a Cam: Introduction
Introduction
02.11
00:01 | - In this worked example, we're going to take a look at the process of degreeing a set of aftermarket Kelford cams to suit our Honda B18C engine. |
00:09 | These cams have been selected to suit a turbocharged application. |
00:14 | At 0.1 millimetre lift they offer 284 degrees duration on the inlet and 274 degrees duration on the exhaust. |
00:23 | They also offer 11.25 millimetres lift on the inlet and 11.0 millimetres lift on the exhaust. |
00:31 | Now when we are dealing with a Honda VTEC engine, it is essential that for the purposes of degreeing the camshaft, we run the cams on the high lobe. |
00:42 | Now there's two ways we can do this. |
00:44 | It is possible to supply compressed air into the oil gallery that supplies the VTEC mechanism. |
00:51 | If we're going to do this, we also need to blank a hole in the back of the cylinder head where we're going to end up with air leaking and this will actuate the VTEC mechanism, pushing the pins to lock the high lobe mechanism in place during the process of degreeing our cams. |
01:08 | In this instance though, we've chosen to disassemble the rockers from number one cylinder and we've mechanically locked the rocker assembly into the high VTEC operating mode. |
01:19 | It's also essential before we begin the process of degreeing our cams to make sure that the lash is set correctly. |
01:25 | In this case our camshaft spec card calls for 0.3 millimetres of lash on the inlet and the exhaust. |
01:33 | In this case it's also important to note that the cam spec card requests that this lash be set with the engine hot. |
01:40 | Now clearly we can't do that when we've got our engine on the stand here, what we do however is set the lash at 0.3 millimetres for our cam degreeing process, once we've actually got the engine in and running, we would then recheck and adjust the lash as required once the engine's up to operating temperature. |
01:59 | So at this point we've got our cylinder head and our camshafts installed and our lash is set and our VTEC mechanism is locked. |
02:07 | Let's move on with the first step of our process. |