Got a problem setting dry tappet clearance. Superior roller lifter bottom end with Lycoming cylinders on a home assembled parallel valve IO-360 with all new parts. I've got 6 valves that I can't get in range. It's supposed to fall between .028 and .080. If I use a Superior -30 pushrod, the clearance is out of range big and if I use a -31, it's out of range small. I'm getting a delta of about .080 when I change pushrod length which is neatly bracketing the .052 allowable range. I have confirmed that the hydraulic units are fully collapsed and that isn't contributing to the problem. Has anybody else had this problem?
Table 3 of:
http://www.lycoming.com/sites/default/files/SI1060L Push Rod Identification.pdf
shows a difference in nominal pushrod length of .023. At 1.28:1 rocker ratio, .023 should move the clearance about .030. I measured the difference in length between 2 of mine at .061 which makes sense with my approximate .080 delta.
I think I have a choice between buying Lyc pushrods and starting the process of finding the right length all over or getting custom rods made. Do you guys think there would be a substantial performance or wear penalty from using adjustable pushrods?
Ed
Table 3 of:
http://www.lycoming.com/sites/default/files/SI1060L Push Rod Identification.pdf
shows a difference in nominal pushrod length of .023. At 1.28:1 rocker ratio, .023 should move the clearance about .030. I measured the difference in length between 2 of mine at .061 which makes sense with my approximate .080 delta.
I think I have a choice between buying Lyc pushrods and starting the process of finding the right length all over or getting custom rods made. Do you guys think there would be a substantial performance or wear penalty from using adjustable pushrods?
Ed