Question on lifter preload and lifter plunger.
09-13-2013, 03:33 PM
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Question on lifter preload and lifter plunger. I was measuring for lifter preload after my car sat over night. With the rocker off and pushrod in I can take my hand and push down onv the pr and feel a light springvpressure of the lifter.
My question is how far intov that light spring pressure do you want to be with the rocker on before you can say you are at zero lash?
If its right at the beginning its still pretty loose. You can take the rocker over the valve and lift it off the valve easily. It will spring back down but its not a lot of pressure. The pr can also be spun very easily.
My question is how far intov that light spring pressure do you want to be with the rocker on before you can say you are at zero lash?
If its right at the beginning its still pretty loose. You can take the rocker over the valve and lift it off the valve easily. It will spring back down but its not a lot of pressure. The pr can also be spun very easily.
09-13-2013, 03:36 PM
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Do you call that zero lash? Or is it when you go alittle past that and the rocker overv the valve is harder to pull up but you still can?
Ive also heard of people tightening just till the point where you cant go right to left with the valve end of therocker and its seated nice and center on the valve. Then v that's called zero lash.
Ive also heard of people tightening just till the point where you cant go right to left with the valve end of therocker and its seated nice and center on the valve. Then v that's called zero lash.
09-13-2013, 05:09 PM
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does the spin of the pr methof not apply to the ls motors. If i get it to where its just barely seated in the lifter the pr is super easy to spin still.
09-13-2013, 07:15 PM
#6
I wouldn't go by spin, just go to 0 lash Plus what ever makes you happy. You could go from 0 lash + 1/8th of a turn to 1 3/4 turn on the nut. As long as you are in that range yer good to go. So once hit 0 you got up to 1 3/4 turn to go and still be ok, GET IT?
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09-19-2013, 10:47 PM
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yes you torque them down and call it a day, once you measure for proper push rod length. If you are totally stock you're fine.
If you had the heads milled, changed the cam stuff like that youv should check. If all you did was a cam a 7.425 length is probably all you need
If you had the heads milled, changed the cam stuff like that youv should check. If all you did was a cam a 7.425 length is probably all you need
09-19-2013, 10:59 PM
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You get the lifter on the base circle of the cam(so valve is closed) you start by putting the pushrod in at stock length. Get to zero lash explained above. Then for Every turn after zero lash is .047 preload. You want .70 to .090. If you can only go a half turn lets say before it torques down you need a longer pr. So you adjusrt it longer and see where your at
09-19-2013, 11:14 PM
#15
09-19-2013, 11:24 PM
#16
IF YOU TIGHTEN ANY FURTHER you are past 0 lash. If you compress the plunger you went too far and past 0 lash.
Once you hit 0 lash COUNT the amount of turns it takes to tighten the nut. If its between 1/8 and 1 3/4 turn you are good to go.
If its less or more you need to change push rods till you get the adjustment YOU FEEL is right...............these are hydraulic lifters, THE ONLY reason for the adjustment to be more than 0 lash is so as the valve train wears it won't be loose and cause wear and noise. SO as long as you have some preload between 1/8 turn and 1 3/4 turn you are close enough. If anyone tells you otherwise they are FULL OF ****.
Please explain to me what you don't understand?
I personally like about 1/2 a turn.............
09-19-2013, 11:37 PM
#17
You get the lifter on the base circle of the cam(so valve is closed) you start by putting the pushrod in at stock length. Get to zero lash explained above. Then for Every turn after zero lash is .047 preload. You want .70 to .090. If you can only go a half turn lets say before it torques down you need a longer pr. So you adjusrt it longer and see where your at
09-20-2013, 08:25 AM
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No i do get it, you read my explanation to him wrong. I was saying to him you still need to find 0 lash to measure. I got, ive been doing this stuff for a long time. Just recently got into a debate with a few other mechanic friends and their methods.
Mine is all set now, i ordered 11/32 pr that are 7.430 long. That will put me right at .70 lifter preload. Its all good that's for the help.
Mine is all set now, i ordered 11/32 pr that are 7.430 long. That will put me right at .70 lifter preload. Its all good that's for the help.
09-20-2013, 03:21 PM
#20
quoted from another page... used to set preload on my lifters... this method is using a comp cams pushrod checker tool... must have..
Pre-load on a LS7 lifter can be .040 - .130. Ive actually tried .040, .075 and .120 and all felt the same, idled the same and taken to 6800 the same. No big difference in noise either. GM specs show that .082 is the sweet spot cold and then as engine is hot that goes to about .075.
You are trying to get to the point where the lifter doesn't "tick tick" with the pushrod in place nor is the rocker snug. When you get the pushrod length such that you just barely get rid of the "tick tick", you have found "zero lash".
10. When you have found zero lash, carefully remove the rocker and pushrod without rotating the pushrod.
11. Tighten the pushrod until it is fully closed counting the turns as you go.
To figure out your pushrod length you do the following. Let’s assume it took 10-1/2 turns to close the pushrod down to its shortest length after you reached zero lash. Each turn is 0.050".
Your length is then: 6.800" (fully closed length) + 10.5 X 0.050" (number of turns times the length change per turn) = pushrod length minus preload. So for this case:
6.800 +10.5 X 0.050 = 7.325"
This is the length you measured to zero lash without any lifter preload. Now let’s say you want to have 0.075" lifter preload, you add that to the measured number and you end up with 7.400" pushrods.
99% of the time whatever PR length you have in there with LS1 lifters will still work just fine with LS7 lifters. When I swapped my ls6 lifters for ls7 lifters I kept my stock length PR's. I didnt need to go .050 shorter at all.
Pre-load on a LS7 lifter can be .040 - .130. Ive actually tried .040, .075 and .120 and all felt the same, idled the same and taken to 6800 the same. No big difference in noise either. GM specs show that .082 is the sweet spot cold and then as engine is hot that goes to about .075.
You are trying to get to the point where the lifter doesn't "tick tick" with the pushrod in place nor is the rocker snug. When you get the pushrod length such that you just barely get rid of the "tick tick", you have found "zero lash".
10. When you have found zero lash, carefully remove the rocker and pushrod without rotating the pushrod.
11. Tighten the pushrod until it is fully closed counting the turns as you go.
To figure out your pushrod length you do the following. Let’s assume it took 10-1/2 turns to close the pushrod down to its shortest length after you reached zero lash. Each turn is 0.050".
Your length is then: 6.800" (fully closed length) + 10.5 X 0.050" (number of turns times the length change per turn) = pushrod length minus preload. So for this case:
6.800 +10.5 X 0.050 = 7.325"
This is the length you measured to zero lash without any lifter preload. Now let’s say you want to have 0.075" lifter preload, you add that to the measured number and you end up with 7.400" pushrods.
99% of the time whatever PR length you have in there with LS1 lifters will still work just fine with LS7 lifters. When I swapped my ls6 lifters for ls7 lifters I kept my stock length PR's. I didnt need to go .050 shorter at all.