Setting Valve Lash
(The easy way)
I get many inquiries about setting lash and many times it seems this method confuses people needlessly. There are other methods, but this one has advantages:
1.1. No need to memorize firing orders ( you don’t even need to know what engine you are working on)
2.2. On most engines, doing one side at a time, you need to turn the engine very little to get to the next valve needing set.
3.3. Quicker than most methods.
Most other methods require you know the firing order, carry a little card to tell you “ find your glasses so you can read this card, put the exhaust valve on #1 on base, wiggle your nose, set #8 intake and # 2 Exhaust, turn the engine 37 degrees”, etc. Most require having both covers off and bouncing from side to side on the car, This is a waste of time , can allow the engine to cool off too much if you are not experienced, allows more chance of dirt in the open engine etc…
I suggest reading this in its entirety before starting.
REFER TO THE BELOW DIAGRAM WHILE READING THIS
The key to understanding this method and remembering it properly is understanding the above diagram. In any 4 cycle engine, the order of events is intake, compression, power, exhaust. This repeats over, so by writing out 2 cycles it becomes obvious that the exhaust valve will open before the intake. Also note that before the exhaust closes completely, the intake begins to open, creating a period of time in which both valves are open. Following that period, the intake opens and closes and then there is a period where both valves are closed. The bigger the cam, the shorter the last period becomes.
On to the method * the following is for solid lifter (flat or roller) cams:
1. Take the valve cover off the driver side after warming the engine up. (Most lash settings are hot measurements-if you adjust them too cold the lash will be too loose)
2. Roll the engine over until #1 Exhaust just starts to open- this insures you are on the front side of the lobe, NOT the overlap side, thereby insuring the intake is not open. At this point, you will adjust the intake lash on that cylinder.
3. Once you have adjusted the intake lash turn the engine until the exhaust opens all the way and closes, and the intake opens and is very nearly closed again. This insures you are on the back side of the intake lobe and the exhaust must be fully closed. The reason for stopping just shy of the intake fully closing is to make sure you don’t go too far and pass thru the both valves closed area and start back opening the exhaust. Adjust the Exhaust valve now.
4. Proceed to the next cylinder and repeat the process until that side is done. On many engines, Mopar and Chevy for example, you will notice you have to do very little turning with the exception of one cylinder on the passenger side- this saves much time and effort.
5. Once the driver’s side is done, proceed to the passenger side while your help reinstalls the driver’s side valve cover they cleaned while you were adjusting the valves…..If you are new at this you will likely need to restart and warm the engine between the driver and pass side adjustments- this is another reason to use this method rather than having both covers off.
To recap, on each cylinder, roll the engine until the exhaust just starts to open and adjust that cylinders intake. Then roll thru the exhaust completely opening and closing, the intake opening and just before it is closed, adjust the exhaust on that cylinder. Repeat until all cylinders are done.
Taken from Diamondback Racing engines Website
