Lack of oil to rear lifters

[My427stang]

We all agree on the potential adjuster issue, but keep in mind that doesn't cause the lifter to make noise with preload correct.  You can run those lifters non-oiling and they are quiet.

If his pushrods are so short he drove it in past the oiling band, but still doesn't have adequate preload maybe, but, I am sort of banking on a bad lifter too unless he used the wrong oil.

Call me crazy but I'd still like to hear how much preload he started with and if he used the EOIC method to adjust

[60sIron]

Yes, I used the EIOC method to adjust the preload.

When the lifter was on the base circle, I would adjust the rocker until I felt resistance turning pushrod indicating that I was at zero lash.  From there I turned the adjuster down another 3/4 turn.  Since it was getting noisy when it warmed up, I tried adding another 1/4 turn, and then a second 1/4 turn.  Since those weren't effective I moved on to looking for other problems.

[My427stang]

That would be somewhere around .062 assuming you started at a good zero.  Seems like preload isn't an issue

Pull the rocker assembly so you can look at your adjusters, you can squirt oil in the hole to see if it flows through.  Blow air through the pushrod.

I am thinking you have a lifter bleeding down which causes the noise.  The Morels are really good, but every so often you see a weird one.

[jayb]

Twisting the pushrod until you feel resistance is a pretty sketchy way to adjust hydraulic lifter pre-load, in my opinion.  You should grasp the pushrod and move it up and down until the clearance is gone, then go another 3/4 turn.  Sometimes, especially if there isn't much oil in the lifter body, you can be pre-loading the lifter for a full turn or more before you start to feel resistance turning the pushrod.  Been there, done that...

[My427stang]

I 100% agree with Jay on the difficulty of feeling resistance when turning, especially the way you have to grab an FE pushrod with your fingers.

I use the movement in the pushrod or rocker too. Even after all these years I still double and triple check, especially if a pushrod length isn't making sense at mockup.  I like to do it initially with the intake off and keep parts in their places on a full build.   Sure not saying I would pull the intake to adjust preload, but if you do swap a lifter or two, maybe do it while the intake is off and keep parts in order. 

However, on the flip side, Morels like preload, and if the engine isn't skipping, too tight wouldn't make a noise.  I keep going back to a sloppy plunger in a lifter for the noise when hot.  Oil thins with heat and it doesn't hold the pressure internally.

[60sIron]

Yes, I came to that conclusion as well.

This weekend, I started up the engine to get it warm because on Facebook someone had said they encountered problems with the T&D spacers getting tight when hot.  This time it made the ticking right away when I started it cold.  Then the ticking came back when it got hot again.  I took the valve covers off, and the front spacer was tight.  So I removed the rocker assembly and took about .015" off the spacer and flipped around the shims on either side of the second tower (one shim is .003 and the other is .009)

Then I looked at the adjusters.  They seemed to be all over the place, but the rockers that had low oil flow were the ones most out (up).  I removed the adjuster and measured the position of the groove in the adjuster relative to the hole in rocker arm and this could be causing a restriction.  Also given they were so far up it could mean not enough preload.  So I recalibrated the pushrod drag method and reset the preload looking for a lot more resistance.  The result was a major gallop indicating at least two cylinders didn't have compression.  I could tell, I was opening some valves when setting the preload, so this wasn't a big surprise.  I tried it and it didn't work.  When I turn the engine over during the lash setting process, the lifters get spongy because I assume the springs squeeze all the oil out of them.  So in my next attempt, I set the lash to take up all the sponginess which I assume is the bottom of the hydraulic travel, then I backed them off 1/2 turn.  This resulted in much more consistent cylinder to cylinder adjustment and everything was in the range to provide good oiling to the rocker arm.

It started and ran quiet until it was fully warmed up and then the ticking returned.  So the problem isn't solved.

I don't think this is a weak lifter problem because I've changed all the lifters once.   The first set of lifters were probably Morels, they came in a Crane box that sat on my shelf for almost 10 years (2007 vintage).  I changed those to a new set of identical lifters from Howard's Cams in 2020.  The lifter change didn't have any effect on the noise.

Could this be as simple as switching from 10W30 to 5W30?  That seems wrong considering the problem shows up when it is hot.

The other thing I'm thinking is some kind of restriction in the oil feeds, but that wouldn't explain why the sound goes away when cold.

I'm kicking myself for never measuring the lifter bores when I was building it, or back in 2020 when I changed out the lifters.  They didn't look bad, and the lifters weren't sloppy in the bores, but that is one area that might be a problem.

[jayb]

After you reset the valvetrain did you look to see if the oiling issue at the back few rockers is solved?  Or did you just assume because of the ticking that there is still no oiling at the rear rockers?  I think it would be worth confirming that there is still no oiling at the rear.

An exhaust leak can sound like a tick, or a knock for that matter.  I thought I had a serious rod knock once, and it turned out to be a header pipe disconnected at the collector.  The point is that it is possible you are chasing two different issues, the rocker oiling and a separate exhaust leak.

I don't know how this could explain your symptoms but you will sometimes see cracks in the block between the main bearing bore and the cam bearing bore, along the oil passage there.  Usually this is on journal 2 or journal 4.  May be related to why the problem shows up hot; when cold the crack closes up, but opens again at higher temperature.

If you suspect the oil could be part of the problem, try a change to Valvoline straight 40 weight or 20W-50, and see how that changes things.