Catching a non-rotating lifter on first startup.

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a70duster

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So a few months ago I was starting a rebuilt 383 (new block, reused the rotaing equipment) and I was super cautious about the cam. I treated the breakin like a new cam/lifters and used breakin cam lube on the lobes and lifters. I used high zinc oil and a ZDDP additive.

I marked all the tops of the lifters with a dab of yellow paint to see the lifters rotate. I removed the valley pan to observe the 16 rotaing lifters and started the engine. Within 10 seconds I discovered that #2 exhaust lifter was not rotating. It was messy BUT I found the problem in less than 20 seconds of run time.

The lifter in question felt convex when faced against another lifter. The cam set was a Crower cam and lifters. I ordered another lifter (solid) and did the break in again. The same issue happened where #2 exhaust didn't rotate.

It was messy but I caught the failure before the lifter wore out and put metal throughout the engine. It's possible that this could be done with just viewing a marks on the pushrods but I can't validate that.



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I got a new Herbert cam and lifters and installed them after discovery the issue with the old cam/lifter. The new cam broke in fine and I used the same method to check the rotation of every lifter. I was in a rush to get the car to Bandimere before it closed for good so I didn't get an ideal cam and I wasn't quite ready to drop $1500 on a roller cam setup. Plus the lead time was at least 6 weeks for a cam.
 
I looked at the video 3 times & 2E seems to be rotating ok. Others are also.

If the lifter base is convex, but does not rotate, most likely cause is no taper or wrong taper on THAT lobe.
 
Don’t forget about lifter bore problems or contamination.
 
Bewy said:
I looked at the video 3 times & 2E seems to be rotating ok. Others are also.

If the lifter base is convex, but does not rotate, most likely cause is no taper or wrong taper on THAT lobe.
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It was not rotating, that is how I caught it. The resolution of the video degraded when uploaded to YouTube. You can see #2 intake rotating clockwise. The splashing oil doesn't help either.
 
413 said:
Don’t forget about lifter bore problems or contamination.
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That was the first thing I checked when I discovered that the lifter didn't rotate. I could push the lifter down in it's bore with a pushrod and rotate the lifter by spinning the pushrod.
 
Demonic said:
I'd be really wondering about the lobe taper.
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That is harder to check on a Mopar cam with the different size cam bearing. One puts a Mopar cam on a flat surface and the cam is on an incline.

I'd guess you could use feeler gauges to prop up the smaller end to level the cam on a flat surface then measure the taper (or lack there of).

The old cam had about 150 quarter mile runs on it.
 
a70duster said:
That is harder to check on a Mopar cam with the different size cam bearing. One puts a Mopar cam on a flat surface and the cam is on an incline.

I'd guess you could use feeler gauges to prop up the smaller end to level the cam on a flat surface then measure the taper (or lack there of).

The old cam had about 150 quarter mile runs on it.
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Could you chuck it in a lathe and put a dial indicator on the tool post? Without rotating the cam run the indicator across the lobe with the tool post.
 
So I chucked up the questionable cam into a lathe and I was able to measure about 1.5 thousandth of taper on ALL the lobes, including the #2 exhaust lobe that the lifter wasn't rotating on.

So the old lifter didn't rotate, the new lifter didn't rotate and a new cam and a set of lifters were fine.

WTF

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Everything else associated with 2 ex is good? Spitballing here....spring? Pushrod? Rocker?
Glad ya caught it asap.
 
4spdragtop said:
Everything else associated with 2 ex is good? Spitballing here....spring? Pushrod? Rocker?
Glad ya caught it asap.
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Yeah, all three lifters in exhaust lifter bore #2 rotated easily. Pushrods were all straight, springs checked out before assembly, adjustable rocker moved freely and the tip was centered over the valve tip. The exhaust valve moved freely in its guide.

I installed the new cam/lifters and I did the exact same 15 second run on startup to confirm that all the lifters were rotating. Then buttoned 'er up and broke in for 20 minutes. I doubled checked valve lash and all 16 measured good.

This is an odd one. I'm super glad that I went through the lengths of checking lifter rotation. If I didn't I wouldn't have made it to the track the last summer.
 
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You shouldn't have to "push" a lifter into its bore. After the initial line up, it should slide into its bore under its own weight. Obviously, this would be checked during part fitment/mock up. Also during this time, you could have installed all the lifters and rotated the cam with a speed handle and visually inspect for rotation. I suspect something with the lifter bore. It doesn't take much to make them NOT rotate. Have you tried swapping some of the other lifters around in that bore?
 
I am rebuilding my 400. It sat for years and the last three lifters on one side were stuck in their bores. Is it a good idea to run a hone quickly through all of the lifter bores to get rid of anything that could hang them up?
 
qkcuda said:
I am rebuilding my 400. It sat for years and the last three lifters on one side were stuck in their bores. Is it a good idea to run a hone quickly through all of the lifter bores to get rid of anything that could hang them up?
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Must be careful if using a small glaze breaker, so as not to remove too much material. The lifters hemmorage bad enough the way it is. It takes an act of God to get the fine debris out when done also.
 
Maybe I screwed up but I just checked for rotation during assembly.
 
408 swinger said:
You shouldn't have to "push" a lifter into its bore. After the initial line up, it should slide into its bore under its own weight. Obviously, this would be checked during part fitment/mock up. Also during this time, you could have installed all the lifters and rotated the cam with a speed handle and visually inspect for rotation. I suspect something with the lifter bore. It doesn't take much to make them NOT rotate. Have you tried swapping some of the other lifters around in that bore?
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When I installed a new cam and lifters, the #2 exhaust lifter rotated.
 
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