Half rebuild on a 4.0L and loud ticking?

I swaped my old motor so before I installed my spare (120k miles on the spare) I decided to change all the seals and gaskets. I also changed the main bearings and took everything apart to clean it out well. I took each lifter apart and made sure to put everything back in it's original locations.

I'm still working out a couple bugs but one thing I wasn't expecting was an intermittent ticking sound that seems like the sound of lifters. I remember having this same sound the odd time on my old engine but I attributed it to sticking lifters and it went away after an engine flush. This time I know the lifters are nice and clean. So far it will do it for a couple minutes...then go away....then come back at not specific time.


Any ideas on what could be the issue?

Thanks

By the way, this was my first time taking apart an engine so I'm not really familiar with trouble shooting methods. I did keep everything very clean, torqued everything to spec, and used oil and assembly grease when reassembling everything.

Did you pump up the lifters before installation? It's usually a good idea, and I've had it cause intermittent clicking for a while before they seem to get the idea...

You pump up a lifter for installation by submerging it in oil and pumping the cap with an old pushrod until it stops bubbling - this allows it to go in full of oil.

By the way - if you didn't use assy lube or oil prior to assembly, it wouldn't cause a "clicking" noise - it would be more like a cross between grinding and CRUNCH! before the bearings all gave way...

Oh - you did remember to prime the oil pump as well, didn't you? It's probably not related to this (either) but it's utterly necessary...

5-90

I primed the oil pump with a screwdriver end on a drill. I did NOT prime the lifters. I just took them apart, cleaned them out, dipped each part in oil and reassembled them.

So how long does it take for the air bubbles to work out? Will this hurt anything?

Would a low weight syn oil help to fix this?

Hell - I don't think going to a full synthetic is necessary. I've done the job by cutting with either DexronIII (high-detergent 10W, essentially) or by finding straight 5W or 10W (both rare!) oil for one change, and that usually does it.

Why take apart the lifters? It's usually better to swap them entirely...

5-90

The engine was still relatively young at about 90K miles (I estimated wrong above, my jeep is in km's) and I am fairly strapped for $$. Generally I've been told lifters break in with a cam and neither should really be replaced without the other. That combined with the fact that I rarely hear of XJ lifters actually go bad but rather just clogging up I figured a little cleaning wouldn't hurt while I was in there.

Thanks for the advice.

Will this damage anything the way it is?

If not, i'll just leave the 10W oil in there for a couple weeks and hopefully the noise goes away...if not I'll try a thinner oil.

What year is the "new" engine? Did you torque down the nuts on the rocker arm studs?

I've got a little more info...

The donor was an 89 XJ with 160k km's on it...about 95k miles.

The ticking doesn't seem to happen when the engine is cold but gets worse as it warms up. If I'm on the throttle it sometimes goes away...i.e. it is worse while just coasting.

I'm having trouble believing this could be air as the noise is fairly loud.

I did torque the rocker arms down to the specs in my Haynes manual. I re-used the original rocker bolts.

The rockers were all in good shape when I was in there and all the rods were straight and in good shape. I checked the oil passages in the rods and they were fine.

I've got about 60 miles on it now with no change so I'm starting to worry a bit here.

Does anyone have any ideas what would cause a lifter to make noises only some of the time?

I figured if it was totally wrecked it would make noise all the time.

I´m not real familiar with the oiling of the 4.0. But guessing, I´d say it is pretty much the same as everybody else`s motor.
I´d look real close at the amount of oil at the rocker. If an oil passage is plugged on the crank, it will oil starve, some of the top of the motor, On one or two lifters, depending on which main has turned in the seat. I learned the hard way to make sure the oil passages on the main bearings, align with the oil ports, in the main bearing seats.
I looked through some of my literature and didn´t find an oiling diagram for the 4.0. If you can figure out which lifter, is making noise, it might be an indicator, if the oil passages are plugged. Which can get real serious real fast. Might also want to find TDC on every cylinder (when both valves are closed) and feel the lash a little, you my be able to tell by spinning and wiggleing the lift rods. if any feel excessively loose. I had a lifter retaining clip pop off of a lifter, on one motor, I´d refurbished, made a racket. Turned out to be not to serious, once I´d found the problem.
I´ve replaced the main bearings in a 4.2 before, had a lot of trouble, getting the right mix and match. Finally, using plasti gauge, I set the motor up a little loose. Worked out well, a little loose is often much better than too tight. I can see, by the design, it would be hard to spin a main bearing in the I 6 motor, but not impossible. A spun bearing would probably mess with the oiling to most everything above the crank, in a cylinder or two. The crank gets oiled first on most motors.
Check for good oiling at the rocker, on every cylinder. Don´t panic, but do a serious inspection, before you run the motor much. Just a thought, they recommend returning the same push rods, into the same spots, for a reason.
The first line on the noisey valve, troubleshooting guide, is oil too thin. Might mostly go away when you switch out the break in oil, to something thicker.