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Please help me with some valve train questions.
We're doing an overhaul and got new lifter hydraulic units (p/n 637269) that were shorter by 0.188" than the previous unit measured from the face where the push rod socket fits to the shoulder where the unit rests in the lifter body. I got a set of new push rods (p/n 537870) to compensate and they are 0.126"longer than the previous ones. So the new total length of the hydraulic unit and push rod is 0.062" shorter than the original (seems to be only one socket p/n).
Here's some details:
Part Old p/n and length (in) New p/n and length (in) Difference (in)
Pushrod ?? 10.625 537870 10.751 0.126
Hydr unit ?? 1.563 637269 1.375 -0.188
Total length 12.188 12.126 -0.062
ASS wrote on the red and yellow tags that came back that my old Lifter Bodies were p/n 21608 and my old Hydr Units were p/n 21609.
The O/H manual says that the hydraulic units are designed to operate with 0.03 to 0.11" lash between the rocker and valve stem when the lifter is deflated. It also says elsewhere that "the light plunger spring (on the hydraulic unit) lifts the hydraulic plunger so that its outer end contacts the pushrod, taking up the clearance at this point and all along the valve train, giving zero lash."
Before disassembly, there was no lash between the rocker and valve stem (due to the spring on the hydr. unit).
My questions:
(1) How do you measure lash when the spring on the hydr unit takes up all the lash? (The spring on the hydr unit is compressed about 0.050" just to get the rocker shaft in place measured with a dial gage before and after the shaft goes in.)
(2) What are the proper part number combinations for this valve train, including lifter body, hydraulic unit, socket, pushrod?
Any other information would be just great.
Thanks for your help sorting out this problem. I get to fly when its solved!!
Bob
We're doing an overhaul and got new lifter hydraulic units (p/n 637269) that were shorter by 0.188" than the previous unit measured from the face where the push rod socket fits to the shoulder where the unit rests in the lifter body. I got a set of new push rods (p/n 537870) to compensate and they are 0.126"longer than the previous ones. So the new total length of the hydraulic unit and push rod is 0.062" shorter than the original (seems to be only one socket p/n).
Here's some details:
Part Old p/n and length (in) New p/n and length (in) Difference (in)
Pushrod ?? 10.625 537870 10.751 0.126
Hydr unit ?? 1.563 637269 1.375 -0.188
Total length 12.188 12.126 -0.062
ASS wrote on the red and yellow tags that came back that my old Lifter Bodies were p/n 21608 and my old Hydr Units were p/n 21609.
The O/H manual says that the hydraulic units are designed to operate with 0.03 to 0.11" lash between the rocker and valve stem when the lifter is deflated. It also says elsewhere that "the light plunger spring (on the hydraulic unit) lifts the hydraulic plunger so that its outer end contacts the pushrod, taking up the clearance at this point and all along the valve train, giving zero lash."
Before disassembly, there was no lash between the rocker and valve stem (due to the spring on the hydr. unit).
My questions:
(1) How do you measure lash when the spring on the hydr unit takes up all the lash? (The spring on the hydr unit is compressed about 0.050" just to get the rocker shaft in place measured with a dial gage before and after the shaft goes in.)
(2) What are the proper part number combinations for this valve train, including lifter body, hydraulic unit, socket, pushrod?
Any other information would be just great.
Thanks for your help sorting out this problem. I get to fly when its solved!!
Bob
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