Anyone rebuild their hydraulic valve lifters?

Here is a link to the page on ZenonCar.com where it is explained how to clean them.
http://xenonzcar.com/z31/RebuildingLifters.html

I figure if they have enough miles on them to be gunked up and are at all in question, pull some from a junkyard motor,
out of a low mileage Quest (that's what we did for a friends 86na) Inspect them for wear and toss any that look questionable.

I had a few that the springs seemed a bit more compressed when compared to others but they seem to be quiet enough.

I soaked mine in ATF for about a week before rebuilding as per the link (wasn't in a rush) it didn't seem to attack the gunk inside.
I then cleaned them in a heated ultrasonic bath (similar to this) using a 1:1 water/Krud Kutter solution before assembly.
That did it. They then sat for another week or five submerged in 5W30 before installation. Not difficult, just time consuming.

As far as I knew, they're self adjusting hydraulic valve lifters so they didn't need as much maintenance and tuning after the P90 from the 280ZX in 1982. I don't even think you can get new ones from Nissan anymore. Many of their parts are NLA. The valves, upper cylinder, and intake manifold tends to get very dirty and gummed up in these VG30E engines. Don't bother using fuel system treatment products like Lucas Upper Cylinder Treatment or Techron Fuel System Cleaner. You need to use it faithfully about five times in a row to see even minor results. Even then, there's still carbon deposits on the cylinder heads. The only one I've ever known to make a difference was the BG 44K Fuel System Cleaner.

https://www.nissanparts.cc/oem-parts…ers-13231v5005

13231-V5014 Superseded to 13231-V5005 12/01/1985 to 07/03/2018

Ah, but here's the thing. I've placed parts in the cart before from wholesale websites then paid for the order. A day or so later I'd get a message from the local dealer saying we're refunding you for your order because the part has been discontinued. I would always double check with the dealer first before ordering to make sure they have them.

Baha, shut down.. . I've rebuilt a set before. Takes a looong time but no dramas afterwards. Just need to make sure there is no major physical damage or wear when you inspect them. And make sure you don't lose any of them jesus clips that hold them together! Most of the time it's carbon in the one way valve that makes them leak down.

I successfully broke down two sets (two engines), and even the low mileage JDM engine lifters were really gross. In fact, they gave me more trouble than the USDM engine from a 2000 Xterra. I suspect oil maintenance in Japan is bad to begin with, since they don't register the vehicles after 100Km anyway - I imagine the owners are less likely to worry about regular oil changes.

The most important tool happened to be a 3/8" cylinder brush that could get down inside the lifer body. Cleaners are no replacement for the ability to scrub. I did also find a couple with bad check-valve assemblies (the ball on the spring at the bottom of the inside). It might have been due to the little pick I used to reach in and pull up the check-valve. The old gunky oil was so bad (even after soaking in cleaner) that I could not work the check-valve out without assistance pulling up on it. You have to depress the ball down on the spring and pull at the same time. I have some extras from another engine that look good.

I started to reassemble them. Takes a bit more time assembling them. Using fresh 10w-30 oil. That oil must not cycle out as fast as the rest of the engine oil in other places. It's pretty nasty in there. This is probably the best way I can see getting a visual on WHY it is important to change your oil regularly.