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I am installing pedestal RR's on a 306 w/ Edelbrock alum heads, 2.02 int, 1.6 ex, TFS 2 cam, edelbrock RPM intake blah blah. I'm installing Scorpion roller rockers and my push rods seem short. I wait for intake to open and then as soon as it closes I install the RR on the exhaust side. MOTOR HAS BEEN ON A STAND FOR A YEAR AT LEAST AND NOT STARTED. So it's obvious the lifters are bled down.
My question, WHAT IS THE BEST WAY TO DETERMINE PUSH ROD LENGTH when lifter are bled down. I do not want to have to pump them up.
Does this method work below?
The pushrod length on a non-adjustable rocker is for lifter preload only and you're shooting for approx. .030 to .080 preload with a standard type lifter. The best way to check with an adjustable pushrod is to make the pushrod shorter than needed. Put the lifter on the low part of the cam lobe (valve closed), put the pushrod in, install the rocker with all hardware and tighten the attaching screw. Lengthen the pushrod (lightly) until you've just taken the up and down movement out (zero lash without depressing the lifter). If the intake manifold is off you can see if you start to depress the lifter. Remove the pushrod measure it and then add the amount of desired preload to the the pushrod length and you're done.
I would suggest checking more than one cylinder as machining variances with heads, cam, block etc. may vary this. If this is not an all out, high rpm race engine you don't have to get carried away as the engine basicily will not perform any different if the preloads vary. As long as you keep it out of valve float the engine only knows it's running with no lash. No you can't use a solid lifter as the pushrod seat height may not be the same as your preloaded hydraulic lifter.
If the valves are close to stock length then you would not have to worry about the rocker to valve contact as it is fixed with the pedestal height.
I am installing pedestal RR's on a 306 w/ Edelbrock alum heads, 2.02 int, 1.6 ex, TFS 2 cam, edelbrock RPM intake blah blah. I'm installing Scorpion roller rockers and my push rods seem short. I wait for intake to open and then as soon as it closes I install the RR on the exhaust side. MOTOR HAS BEEN ON A STAND FOR A YEAR AT LEAST AND NOT STARTED. So it's obvious the lifters are bled down.
My question, WHAT IS THE BEST WAY TO DETERMINE PUSH ROD LENGTH when lifter are bled down. I do not want to have to pump them up.
Does this method work below?
The pushrod length on a non-adjustable rocker is for lifter preload only and you're shooting for approx. .030 to .080 preload with a standard type lifter. The best way to check with an adjustable pushrod is to make the pushrod shorter than needed. Put the lifter on the low part of the cam lobe (valve closed), put the pushrod in, install the rocker with all hardware and tighten the attaching screw. Lengthen the pushrod (lightly) until you've just taken the up and down movement out (zero lash without depressing the lifter). If the intake manifold is off you can see if you start to depress the lifter. Remove the pushrod measure it and then add the amount of desired preload to the the pushrod length and you're done.
I would suggest checking more than one cylinder as machining variances with heads, cam, block etc. may vary this. If this is not an all out, high rpm race engine you don't have to get carried away as the engine basicily will not perform any different if the preloads vary. As long as you keep it out of valve float the engine only knows it's running with no lash. No you can't use a solid lifter as the pushrod seat height may not be the same as your preloaded hydraulic lifter.
If the valves are close to stock length then you would not have to worry about the rocker to valve contact as it is fixed with the pedestal height.