How to Degree a Cam: Considerations for Hydraulic Lifters
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Considerations for Hydraulic Lifters
03.00
| 00:00 | - By far the most popular option for valve actuation in modern engines is with hydraulic lifters. |
| 00:06 | This goes equally for push rod and overhead cam engines. |
| 00:10 | As we've already discussed earlier in the course, the hydraulic lifter offers some advantages in terms of reducing engine maintenance requirements but it does make our task a little tougher when it comes to degreeing the cam. |
| 00:22 | This is because the lifter may quite likely bleed down during the degreeing process, affecting the relationship between valve lift and cam lift and making it impossible to degree the cam properly. |
| 00:34 | There are a few solutions to this problem and possibly one of the tidest options is to have on hand an aftermarket solid lifter that can be temporarily fitted for the purpose of degreeing the cam. |
| 00:46 | With the solid lifter installed, we'll also need to adjust either the rocker or the lifter itself to set the valve lash to zero before we start the degreeing process. |
| 00:56 | Many of the aftermarket solid lifter kits available for overhead cam engines offer a simple screw adjustment system to allow the lash to be easily zeroed with the lifter installed. |
| 01:08 | Alternatively on a push rod engine the lifter is not adjusted but instead the valve lash adjustments are made via the rockers. |
| 01:15 | In some push rod engines that utilise hydraulic lifters, the process of swapping a hydraulic lifter temporarily for a solid lifter, can be very time consuming. |
| 01:25 | In these engines, a preferable technique is instead to remove the rocker gear during the process of degreeing the cam. |
| 01:33 | In this instance we're going to locate our dial indicator directly on the end of the push rod. |
| 01:39 | With just the mass of the push rod and our dial indicator acting on the hydraulic lifter, the lifter won't bleed down during the process of degreeing the cam. |
| 01:48 | In this instance we'll be directly measuring our cam timing events instead of our valve timing events. |
| 01:56 | If you have some spare hydraulic lifters lying around for your particular engine, you can also make your own check lifter for the purpose of degreeing the cam. |
| 02:05 | In this instance, the lifter can be modified by removing the internal check valve assembly and replacing it with a solid shim or alternatively it can be tack welded solid. |
| 02:17 | If you have access to tig welding equipment then you can actually do this in some overhead cam engines with the lifter in place. |
| 02:24 | You just want to install all of the valve train parts and locate the cam so that it's running on the base circle. |
| 02:31 | At this point the lifter should be pumped up to provide zero lash clearance and a couple of small tacks with the tig will fix the lifter in this position. |
| 02:40 | Note that I don't recommend using mig welding for this task because a mig causes weld spatter which is inevitably going to end up inside your freshly built engine. |
| 02:51 | It should go without saying that following the cam degreeing process, it's essential to remove your solid check lifter and replace it with the hydraulic lifter. |
