#21  
Old 03-08-2021, 12:39 AM
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Well, on my engine startup last year with all the right parts, Melling 068, Hylift lifters, right oil etc. Had a couple of lifters that were not turning consistently after about 20 minutes. No real damage apparent, some scuffing on the suspect lifters .... ehhh, had it apart for the inspection, figured a new cam was about $100, had a set of NOS Pontiac lifters .... thought what the heck, put them in and try again. Next time things went right.

Who knows, original setup might have been fine. But to try again was maybe $250 in parts and the opportunity to take even more care in assembly, so why not.

For what it's worth, I checked the face of all the lifters for perpendicularity with the lifter body in a metal lathe, and the NOS Pontiac were the best with no measureable run-out, the US made Mellings (some are not) a very, very close second, and contrary to most people's experience the Johnson Hylifts were the worst of the bunch.

Not a topic to start here but I have my own theory about common HFT failures these days, I think it's mostly due to improper cam lobe taper, lifter face crown machining or a mismatch between the two. They HAVE to work together, and lobe tapers vary cam to cam, and crown height/radius varies lifter to lifter, they don't all work with each other. Almost certainly NOT pertinent to your issue as you state yours were all turning nicely, which is a good indicator of well matched lobes and lifters.

See attached photo. A couple of Hylifts from the cylinder I was having problems with, images make them look way worse than they were, there was no detectable surface flaw in the lifter face other than visually. Does the pattern on one of the lifters look familiar? That was the "slow" turner, the bar pattern on the other ... that was the NO turner ... (unless I grabbed the pushrod while it was running and helped it along). Personally I was not that concerned about the one with the circular pattern, I was concerned about the one with the "bar" pattern, not good. Images make it look like there was heat discoloration, there was NOT on either lifter, just trick of the light.

See how the wear on the lifter with the bar pattern is perfectly centered on the lifter face with an ring of no contact around the outer edge. If the taper and crown match perfectly there should have been contact almost all the way to the very edge of the lifter face, that proper offset contact is what keeps the lifter turning. On the other "slow" turning lifter you also see that ring of no contact on the lifter face.

I'm by no means a cam/lifter expert of any kind, but I would say these lifters indicate a lifter with too much crown, or a cam with too little taper which did not present enough offset contact area to keep the lifters turning consistently. But again, that's just a theory, not supported by any measurements I have taken.

Again, probably not that applicable to your situation, but interesting none the less

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Last edited by dataway; 03-08-2021 at 01:20 AM.
  #22  
Old 03-08-2021, 01:30 AM
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If by any chance you are doubting the lifters you used. Here is the TOTAL runout of the typical GM NOS lifters I checked. Why do I care? Ever see a pushrod that makes one turn and stops, then you give a twist by hand and it makes one turn and stops etc.? If the face is not perpendicular the bore that's what it will do as the offset contact point doesn't provide enough motivation for the lifter to climb the "high" point of the non-perpendicular face.

This not the starting picture ... this is the maximum runout I could find.

Forget what the crown was .. but I remember they were very, very consistent.

I also noted that the NOS GM lifter had a very pronounced chamfer on the face edge compared to the others (the Melling have the second largest), presenting a very smooth contact point to the lobe, unlike the sharp edges I have seen on many aftermarket lifters.




Last edited by dataway; 03-08-2021 at 01:37 AM.
  #23  
Old 03-08-2021, 02:54 PM
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Here is the picture that was supposed to be included in the last post.

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