Hi everyone
Hyd lifter valve adjustment
Loosen of till pushrod rotates and then screw down 3/4 of a turn
Is this accurate enuff
What does doing down tighter do
Thanks for teh help
VALVE LASH
Moderator: Team
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bill jones
- Guru
- Posts: 2650
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
- Contact:
Type of engine
Its an Australian Holden V8
basically its a 350 chev, all stuff is the same
It has 1/26 screw in studs as well
basically its a 350 chev, all stuff is the same
It has 1/26 screw in studs as well
-
bill jones
- Guru
- Posts: 2650
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
- Contact:
-If the engine is used for racing I don't like the idea of having the pushrod loaded any more than zero or maybe 1/8 of a turn.
-When you have the adjustment nut preloaded 3/4 of turn like on a 7/16-14 threads per inch stud there is .071" pushrod and lifter plunger preload for each full turn of the adjustment nut.
-This is .053" at 3/4 turn that the pushrod is pushing the plunger down.
-then if you have a 1.5:1 rocker ratio that number ends up at .0795".
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-So what happens here is two things:
1-is the rocker geometry is affected just like you change the pushrod length.
2-when the engine gets to the "valve float" rpm, the pressure goes away at the pushrod so the hydraulic oil pressure will pump the lifter plunger up and as soon as the rpm comes back down and the valve train gets to following the cam lobes again, you end up with the valves open that .0795" momentarily.
-It takes time for the lifters to "bleed" back down and get all settled back to normal so in the mean time the engine acts dead and or the valves make contact with the pistons.
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-I feel that for racing you should have the preload as loose as zero and use the correct length pushrods necessary to get the rocker geometry happy.
-When you have the adjustment nut preloaded 3/4 of turn like on a 7/16-14 threads per inch stud there is .071" pushrod and lifter plunger preload for each full turn of the adjustment nut.
-This is .053" at 3/4 turn that the pushrod is pushing the plunger down.
-then if you have a 1.5:1 rocker ratio that number ends up at .0795".
---------------------------------------------
-So what happens here is two things:
1-is the rocker geometry is affected just like you change the pushrod length.
2-when the engine gets to the "valve float" rpm, the pressure goes away at the pushrod so the hydraulic oil pressure will pump the lifter plunger up and as soon as the rpm comes back down and the valve train gets to following the cam lobes again, you end up with the valves open that .0795" momentarily.
-It takes time for the lifters to "bleed" back down and get all settled back to normal so in the mean time the engine acts dead and or the valves make contact with the pistons.
------------------------------------------------
-I feel that for racing you should have the preload as loose as zero and use the correct length pushrods necessary to get the rocker geometry happy.