FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Dptmachine on March 17, 2026, 09:14:47 AM
-
Measuring for pushrods variation in lengths Question;
1) I am building a 445 stroker with most parts and pieces from Lykins Motorsports. Trickflow heads, Precision Oil Pumps stands/rockers/shafts, fasteners.
2) I am using Morel hydraulic roller lifters
3) I am using Smith Brothers pushrod length tester, .001" dial indicator.
Process
1) It's my understanding the landing pad on TF heads comes tall for most application of stands to accurately setup valve train geometry. I cut the stands .128" measuring from the base of stand to the open bore of the rocker stand. (side note; I found the outer stands are different lengths vs interior stands including variations w/in the groups as well. If found I had to measure each stand and adjust the BP mill each time. This was determined by the variation in overall height differences and having to use the top of the standing as the base in the machine vice.)
2) My bases are now .761" +/- .001", roller tip engaged in the middle of the valve tip, a wider profile pattern than I would like (or referenced web)
3) head gasket installed, valve train mocked-up
4) I loosen the valve train to lift the Smith Brother device out and measure for PR length, re-tighted to measure the next
5)**The issue is I measure #1 thru #4 ex/In w/ variation between 8.618" thru 8.665"; I used the same lifter pair to be consistent. Measure with checker to just engaging the rocker of "0" motion.
6) My thoughts are (lying in bed this AM); does TF head valve seat have variations, does the valve lash on the adjuster need to be "0" or predetermined location?
7) Does the lifter need to be pumped-up with oil?
Thanks for input, I am posted on FE engine enthusiast FB site as well.
**I am in an engine machine class; personal enrichment.
GA
-
Yes, you will get variations just due to manufacturing tolerances. If you also have adjustable rockers, the adjuster has to be in the exact same spot and even a 1/4 turn will get you ~.015" or so difference.
Lifter does not need to be pumped up, you're just measuring from point A to point B, without putting a load on the lifter.
You should be able to get a ~.050" wide contact pattern near the center of the valve stem. Remember, the contact patch doesn't have to be dead centered, it can be either side of center and be fine. You're looking for the smallest pattern, not perfectly centered.