Adjusting solid lifters
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==Adjusting lash== | ==Adjusting lash== | ||
{{Note1}}Expect the lash to change on a new cam and lifters (not a lot, but noticeable) until the valve train is bedded in together. Once this is done, you won't need to adjust the lash very often, although you still need to occasionally check it. A good time to check the lash is at oil change intervals or before competition. | {{Note1}}Expect the lash to change on a new cam and lifters (not a lot, but noticeable) until the valve train is bedded in together. Once this is done, you won't need to adjust the lash very often, although you still need to occasionally check it. A good time to check the lash is at oil change intervals or before competition. | ||
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# After the intake valve has been adjusted, continue to rotate the engine, watching that same intake valve. The intake valve will go to full lift and then begin to close. When the intake is almost closed, stop and adjust the exhaust valve on that particular cylinder. (Again, when we see the intake valve almost closed, we are sure that the exhaust lifter is on the base circle of the lobe.) Use the feeler gauge and follow the procedure described before in step 3. | # After the intake valve has been adjusted, continue to rotate the engine, watching that same intake valve. The intake valve will go to full lift and then begin to close. When the intake is almost closed, stop and adjust the exhaust valve on that particular cylinder. (Again, when we see the intake valve almost closed, we are sure that the exhaust lifter is on the base circle of the lobe.) Use the feeler gauge and follow the procedure described before in step 3. | ||
# Both valves on this cylinder are now adjusted, so move to your next cylinder and follow the same procedure again. In the future you may find shortcuts to this method, but it still remains the best way to do the job correctly. | # Both valves on this cylinder are now adjusted, so move to your next cylinder and follow the same procedure again. In the future you may find shortcuts to this method, but it still remains the best way to do the job correctly. | ||
| + | # Another and far superior method of adjusting the valves is to hand rotate the engine to bring up each piston in the firing order sequence. With the piston at TDC for that cylinder, both the intake and exhaust valves can be adjusted. You then rotate the engine 90 degrees and adjust the next cylinder in the firing sequence. The easy part of this is that you do not have start with number 1 cylinder, you can start with any cylinder and then follow the firing order. Once you have performed valve adjustment in this manner you will find that it is far faster and more accurate than other methods. You can also use it for what are considered tight lash cams or the infamous Duntov cam for the small block Chevy. Using the previously described method of EOIC (Exhaust Opening, Intake Closing) on tight lash cams will get you into trouble every time. | ||
===Using Valve Lash to Help Tune the Engine (aka "lash loop")=== | ===Using Valve Lash to Help Tune the Engine (aka "lash loop")=== | ||
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*If the engine is running normally, take both cold and hot lash readings. Those reading will obviously be close to the correct lash for that cam and engine. | *If the engine is running normally, take both cold and hot lash readings. Those reading will obviously be close to the correct lash for that cam and engine. | ||
*If nothing is known about the cam and the engine isn't running, and the unknown cam has to be used, regardless- set the valves cold to 0.016" for an iron head and block engine. 0.016" is used because it's basically at the top of the "tight lash" range, and at the bottom of an old-school cam's wider settings. What you do NOT want to do is set the lash too loose! If you have aluminum heads, go 0.004" to 0.006" tighter on the cold lash. | *If nothing is known about the cam and the engine isn't running, and the unknown cam has to be used, regardless- set the valves cold to 0.016" for an iron head and block engine. 0.016" is used because it's basically at the top of the "tight lash" range, and at the bottom of an old-school cam's wider settings. What you do NOT want to do is set the lash too loose! If you have aluminum heads, go 0.004" to 0.006" tighter on the cold lash. | ||
| − | *Most cams have an ID engraved or stamped into them, often on the back end of the cam. The lift and duration @ 0.050" can also be measured if the equipment to degree the cam is available. | + | *Most cams have an ID engraved or stamped into them, often on the back end of the cam. The lift and duration @ 0.050" can also be measured if the equipment to degree the cam is available. |
| + | *Most cam manufacturers will actually recommend setting (hot) lash on an unknown camshaft to .020/.020, and since you would be setting the lash cold in most instances, a very safe bet is to set the lash to .015/.015 for the initial start up. Assuming that there are no issues with the valve train and engine is running correctly. A lash loop can be performed to find the optimal setting for the camshaft. | ||
==Special instructions for Duntov 30-30 cam== | ==Special instructions for Duntov 30-30 cam== | ||
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