Adjusting solid lifters
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[[File:Adj solid lifters ford.jpg|right]] | [[File:Adj solid lifters ford.jpg|right]] | ||
| − | + | ==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. | ||
| − | == | + | ==Manufacturer's cold adjustment/first start up recommendations== |
| + | Because all engines are different, be sure to use this as a guide only. Checking what '''''your''''' engine does is important because of the variables involved. | ||
*In many cases the hot lash setting may be used for initial start-up unless the manufacturer's instructions say to do otherwise. If there's any question as to what cold lash to use for start up, refer to manufacturer's instructions. | *In many cases the hot lash setting may be used for initial start-up unless the manufacturer's instructions say to do otherwise. If there's any question as to what cold lash to use for start up, refer to manufacturer's instructions. | ||
| − | *After the engine is hot, the valves | + | *After the engine is hot, the valves are to be adjusted to their correct hot lash setting. |
| + | *Then after a '''complete''' cool-down (overnight is good), the lash is remeasured and recorded for future use when checking/setting the lash ''cold''. That will get it '''right''' as opposed to ''close''. | ||
| − | + | ===Comp Cams=== | |
| + | ;Setting Solid Lifter Valve Lash | ||
| + | Consult the cam spec card for the correct lash specification. All COMP Cams® spec cards list the “hot” (operating temperature) lash setting, but it will also work for initial start-up. | ||
| − | === | + | ===Crane=== |
| − | The | + | The same basic adjustment procedure (as used with hydraulic lifters) should be used for mechanical lifter cams. Instead of lifter preload, you must use the clearance specs on the cam card for your cam. |
| − | + | Also see '''[[Adjusting solid lifters#Compensating for a Cold Engine when Adjusting Valve Lash|Info from Crane]]'''. | |
| − | + | ===Lunati=== | |
| + | To adjust VALVE LASH ON MECHANICAL (solid) LIFTER CAMS, follow the same basic procedure as above (adjust with lifter on base circle of cam). Instead of hydraulic lifter | ||
| + | pre-load and zero lash, use the valve lash specs printed on your Lunati cam spec card. | ||
| − | + | ==Tips== | |
| + | *On a SBC and most other V8s, you can cut the center out of an old valve cover to use when setting lash hot, engine running. It will keep most of the oil from splashing out. *Using feeler gauges bent at a 45 degree angle (you can bend them yourself) will often make adjustments easier. | ||
| + | *If you use polylocs, using a valve adjusting tool like shown below can make things easier. A tool like that can even help when setting the lash cold because it's easier to get the same 'feel' from valve to valve. | ||
| + | [[File:Valve adjus tool.jpg]] | ||
| − | A go/no-go feeler set is not expensive and will make checking the lash ''uber'' easy. Use a standard feeler gauge for adjustment, not the go/no-go feelers. | + | *A go/no-go feeler set is not expensive and will make ''checking'' the lash ''uber'' easy. Use a standard feeler gauge for adjustment, not the go/no-go feelers. The two sizes on one blade are usually 0.002" apart so the first, thinner section will fit but the thicker step shouldn't if the valve is in adjustment. |
[[File:Go-no go valve feeler.jpg]] | [[File:Go-no go valve feeler.jpg]] | ||
| − | ==Info from Crane | + | ==Info from Crane== |
All pushrod engines using mechanical (solid) lifters, or mechanical roller lifters, must have an adjustable valve train so that precise adjustment for "Valve Lash" can be made to match the camshaft's requirements. Valve lash is the running clearance that exists between the tip of the valve stem and the valves mating surface of the rocker arm. (It is expressed in the Crane Catalog as "Valve Lash" and on the camshaft specification card as "Valve Setting". Both terms mean the same thing.) | All pushrod engines using mechanical (solid) lifters, or mechanical roller lifters, must have an adjustable valve train so that precise adjustment for "Valve Lash" can be made to match the camshaft's requirements. Valve lash is the running clearance that exists between the tip of the valve stem and the valves mating surface of the rocker arm. (It is expressed in the Crane Catalog as "Valve Lash" and on the camshaft specification card as "Valve Setting". Both terms mean the same thing.) | ||
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For this reason, Crane requires that the valve lash be set with the engine "Hot" on all pushrod engines using mechanical lifters. This will insure that the minimum required clearance (valve lash) is maintained throughout the engine's operating temperature range. | For this reason, Crane requires that the valve lash be set with the engine "Hot" on all pushrod engines using mechanical lifters. This will insure that the minimum required clearance (valve lash) is maintained throughout the engine's operating temperature range. | ||
| − | + | ===Compensating for a Cold Engine when Adjusting Valve Lash=== | |
When installing a new cam, the engine will be cold but the lash specifications are for a hot engine. What are you to do? There is a correction factor that can be used to get close. We mentioned that the alloy of the engine parts can be affected by thermal expansion in different ways, therefore the amount of correction factor to the lash setting depends on whether the cylinder heads and block are made out of cast iron or aluminum. | When installing a new cam, the engine will be cold but the lash specifications are for a hot engine. What are you to do? There is a correction factor that can be used to get close. We mentioned that the alloy of the engine parts can be affected by thermal expansion in different ways, therefore the amount of correction factor to the lash setting depends on whether the cylinder heads and block are made out of cast iron or aluminum. | ||
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[[File:Crane lash table.jpg|center]] | [[File:Crane lash table.jpg|center]] | ||
| − | {{Note1}}Remember this correction adjustment is approximate and is only meant to get you close for the initial start up of the engine. After the engine is warmed up to its proper operating temperature range, you must go back and reset all the valves to the proper "hot" valve lash settings. | + | {{Note1}}Remember this correction adjustment is approximate and is only meant to get you close for the initial start up of the engine. After the engine is warmed up to its proper operating temperature range, you must go back and reset all the valves to the proper "hot" valve lash settings.<br> |
| + | ;Return to [[Adjusting solid lifters#Manufacturer's cold adjustment/first start up recommendations|''Manufacturer's cold adjustment'']], above. | ||
| − | + | ===Setting Valve Lash on Mechanical Cams=== | |
All the valves must be set individually and only when the lifter is properly located on the base circle of the lobe. At this position the valve is closed and there is no lift taking place. How will you know when the valve you are adjusting is in the proper position with the lifter on the base circle of the cam? This can be accomplished by watching the movement of the valves. | All the valves must be set individually and only when the lifter is properly located on the base circle of the lobe. At this position the valve is closed and there is no lift taking place. How will you know when the valve you are adjusting is in the proper position with the lifter on the base circle of the cam? This can be accomplished by watching the movement of the valves. | ||
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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")=== | |
Ideally, the cam- if selected carefully- should be right when using the manufacturer's recommendations for lash and phasing (advance/retard vs. the crankshaft). But if there have been changes made to the engine or the cam isn't ideal, using a "Lash Loop" will point you in the direction the engine needs when replacing the cam. | Ideally, the cam- if selected carefully- should be right when using the manufacturer's recommendations for lash and phasing (advance/retard vs. the crankshaft). But if there have been changes made to the engine or the cam isn't ideal, using a "Lash Loop" will point you in the direction the engine needs when replacing the cam. | ||
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This shows the engine a smaller cam with slightly less actual running duration and lift. You can use this method on a trial basis to see what the engine responds to and keep the setting that works the best. Just remember, the more lash you run, the noisier the valve train will be. If the clearance is excessive it can be harsh on the other valve train components. Therefore, for prolonged running of the engine we do not recommend increasing the amount of hot lash by more than +0.004" from the recommended setting. Nor do we recommend decreasing the hot lash by more than -0.008". | This shows the engine a smaller cam with slightly less actual running duration and lift. You can use this method on a trial basis to see what the engine responds to and keep the setting that works the best. Just remember, the more lash you run, the noisier the valve train will be. If the clearance is excessive it can be harsh on the other valve train components. Therefore, for prolonged running of the engine we do not recommend increasing the amount of hot lash by more than +0.004" from the recommended setting. Nor do we recommend decreasing the hot lash by more than -0.008". | ||
| − | + | ===Tight lash warning=== | |
"Tight Lash" camshafts cannot deviate from the recommended hot lash setting by more than +0.002" ''increase'', or -0.004" ''decrease''. "Tight Lash" cams are those which have recommended valve settings of only 0.010", 0.012", or 0.014" on the specification card. These lobe designs have very short clearance ramps and cannot tolerate any increase in the recommended valve lash. The extra clearance can cause severe damage to valve train components. | "Tight Lash" camshafts cannot deviate from the recommended hot lash setting by more than +0.002" ''increase'', or -0.004" ''decrease''. "Tight Lash" cams are those which have recommended valve settings of only 0.010", 0.012", or 0.014" on the specification card. These lobe designs have very short clearance ramps and cannot tolerate any increase in the recommended valve lash. The extra clearance can cause severe damage to valve train components. | ||
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In the cases where the cam is unknown and proper measurements impossible, the following may help: | In the cases where the cam is unknown and proper measurements impossible, the following may help: | ||
*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". 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 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. | ||
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| + | ==Special instructions for Duntov 30-30 cam== | ||
| + | [[Media:30-30 cam adjust.pdf|Duntov and other Chevy solid cams]] | ||
| + | |||
| + | ==References== | ||
| + | *[http://www.compcams.com/Instructions/Files/145.pdf Comp Cams] | ||
| + | *[http://www.cranecams.com/uploads/instructions/214e_.pdf Crane Cams] | ||
| + | *[http://www.sportcompactonly.com/manuals/Brand/Earls/INST150.pdf Lunati] | ||
| + | *[http://www.iskycams.com/ Iskenderian] | ||
==Resources== | ==Resources== | ||
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