Adjusting a valve lash is a pretty delicate and complicated task. A lot of people don’t know what the right procedure is and you may get different opinions on the subject by different mechanics. If you need to make a valve adjustment, you have to make sure you do it properly, since a poorly adjusted valve can do a lot of harm to the engine. You must figure out a couple of things before you start adjusting your valve, such as what lifter camshaft type you are using, whether all the valvetrain parts are working properly, and whether you intend to use your car for racing or for normal, everyday driving.
There are various types of camshafts, including hydraulic, solid roller, solid and hydraulic roller camshafts. The main difference between solid and hydraulic camshafts is that the solid ones have a C clip, and the hydraulic camshafts have wire clips. Adjustment for solid lifters is a bit more difficult than it is for hydraulic lifters.
If you want to adjust hydraulic lifters, you first have to make sure that the pushrods are pre-oiled and the oil pump is primed. The pushrods have to be installed in the center of the lifter, and you must make sure that all the lifters are fully collapsed. You should start adjusting the intake valves first. You should rotate the pushrod in order to loosen the adjusting nut until you get the desired lash. Then, rotate the engine clockwise some more, and start tightening the adjusting nut so that the intake valve gets maximum lift.
After you’ve adjusted the intake valves to the proper lash, you can move over to the exhaust valves. The process is pretty similar to the intake valves adjustment. You start by turning the engine until you get the intake pushrod all the way up, and you have to make sure it goes a little bit over maximum lift. Now the intake and the exhaust valves should have the proper lash.
If you need to adjust a solid lifter camshaft, the main thing you should have in mind is that you have to adjust one valve on one cylinder at a time. You start with the intake valve, which you can adjust by loosening the adjusting nut until there is a little lash on the rocker arm. You can see what the proper lash is in the camshaft specification card. Insert the feeler gauge between the top of the valve stem and the rocker arm tip. Then start tightening the adjusting nut while moving the feeler gauge back and forth at the same time, so that you know when it’s
properly tightened. You should stop tightening the moment you notice some drag between the valve stem and the rocker arm tip. You have to make sure that the solid lifter camshaft is adjusted as precisely as possible, but under no circumstances should it be too tightly adjusted, because it can result in a burned valve.
To sum up, you can do a proper valve adjustment if you have the necessary tools, follow the above-mentioned steps and do it carefully, and you should be able to do it fairly quickly without damaging the valves or the engine in the process.
Jordan Perch is an automotive fanatic and green cars specialist. He is an author of many how-to articles related to safe driving, green technologies, auto insurance etc. Currently blogging for DMV.com.