Possible solution to HPFP bucket failure

[SnowNYC1]

Hey what's up guys.
so yesterday I replaced my HPFP and lifter bucket as my pump was on its way out.
In the process I've stumbled on something interesting.
1st. Infiniti is terrible at doing their own work. They used silicone on the mounting surface of my hpfp when they reinstalled it making it no seat properly and rust badly, we were scraping it off the mounting area on the timing cover


2nd. there seems to be a small hole on the inside of the mounting surface for the pump on the timing cover that is used for oil circulation.
Photo courtesy of Shane Hall
This is the passage way as seen from the inside of the cover


crude little drawing of the top


Now nowhere I've seen anyone bring this hole up in regards of the pump situation and pre mature bucket failure.
we shot compressed air down the hole and were able to unclog it. When it clogs up it most likely starves the cam lobe and bucket of oil, causing metal to metal contact
and making the bucket and lobe wear out prematurely.
This probably why some people experience failure of the new bucket so soon after replacing. They don't clean that passage out and the new bucket just starts wearing out asap.

my bucket after i pulled it out.

[VStar650CL]

Wow. That makes perfect sense, good catch!

[Yoda's Master]

but if you blow it in fron the lifter bucket hole, then doesn't that mean tit's going to clog the hole again when you run the engine?

[VStar650CL]

but if you blow it in fron the lifter bucket hole, then doesn't that mean tit's going to clog the hole again when you run the engine?

I'd imagine a solvent bath would be in order, to make sure it stays open. But the premise makes perfect sense, the lifter has to get lubrication from somewhere and that means oil flow, not just oil. Whether that passage is pressure or return, a blockage is a blockage in terms of impeding proper flow. Kudos to the OP, that's some brilliant detective work.

[Yoda's Master]

but if you blow it in fron the lifter bucket hole, then doesn't that mean tit's going to clog the hole again when you run the engine?

I'd imagine a solvent bath would be in order, to make sure it stays open. But the premise makes perfect sense, the lifter has to get lubrication from somewhere and that means oil flow, not just oil. Whether that passage is pressure or return, a blockage is a blockage in terms of impeding proper flow. Kudos to the OP, that's some brilliant detective work.

i agree lubrication is important, just saying it might not be as simple as blowing it upstream just for it to clog right back up. maybe vacuum it out instead?

[VStar650CL]

i agree lubrication is important, just saying it might not be as simple as blowing it upstream just for it to clog right back up. maybe vacuum it out instead?

With any clog, you do whatever you need to do. There are lots of ways to clean out a blocked passage. But the premise reminds me very much of the idiot thermostats on CVT beehives -- something the FSM barely touches and nobody thinks to routinely check, but which could easily cause repeated failures with no one the wiser.

[Ilya]

I had the bucket replaced under the recall (78kmi), then did it again (124kmi). Is this something I need to go back in there to do? Also, RE: the blowing vs vacuuming...isn't this thing in your hand? Why would that matter? Or is it only in the hand of the OP during his investigation but in a traditional lifter buck swap would still be on the car? I'm not sure I can tell exactly what part this is on.

[VStar650CL]

I had the bucket replaced under the recall (78kmi), then did it again (124kmi). Is this something I need to go back in there to do? Also, RE: the blowing vs vacuuming...isn't this thing in your hand? Why would that matter? Or is it only in the hand of the OP during his investigation but in a traditional lifter buck swap would still be on the car? I'm not sure I can tell exactly what part this is on.

The passage is the tiny hole in the second pic, which is the timing cover removed from the engine. The lifter is the third pic, it rides in the bore visible behind the oil passage. Without removing the cover, you might be able to blow it clean back toward the crankcase by pulling the pump and lifter to expose the bore, then using a right-angle air pistol attachment or flexible hose to blow it clear from inside the bore hole. Definitely worth trying if your second bucket only lasted 46K miles.

[Ilya]

Gotcha, it's on the timing cover which is not removed when just replacing the bucket (based on my experience). Also, I did it as preventive maintenance after the community started worrying about the bucket since it was cheap to do...my bucket had no issues I could tell (the one that was installed by Lia Infiniti at 78kmi): post6799887.html#p6799887

I replaced my bucket today. I saw some discoloration in the center like Ed did but otherwise no issues. New one is in and working great. Didn't do anything with the studs or o-ring.

[VStar650CL]

If I'm getting the topology right in my head, this should be the exposed exit for the spithole. Its job would be to meter oil to the top of the lifter and trickle oil down the sides of the bore.

[VStar650CL]

This is looking more and more like @SnowNYC1 has discovered the whole problem with disintegrating HPFP buckets. Check out LU-21 here:
https://www.nicoclub.com/service-manual ... 1%2FLU.pdf

The HPFP is shown as an afterthought in the schematic drawing and not shown at all in the flowchart. They don't show flow through it, which is important because it means it's a terminus for the oil. I.e., the oil is returning to the crank when the HPFP is done with it. We know HPFP failures don't usually affect the rest of the cam, which confirms that oil starvation in the bucket isn't starving anything else. I can't find it addressed anyplace in the FSM, so I can only conclude that it's a hidden danger that's gone right past all of us until now. With the passage on top and accessible, anybody with a DGI VK should probably make a blow-clear for that passage part of regular maintenance. Thank you @SnowNYC1!

[Ilya]

Sorry for being dense, but we should make removing the timing cover part of regular maintenance? Isn't that...a tough job for a DIY mechanic?

[VStar650CL]

Sorry for being dense, but we should make removing the timing cover part of regular maintenance? Isn't that...a tough job for a DIY mechanic?

No, look where the red arrow is. All you should need to do is pop the pump and apply air, the lifter won't even need to come out. If the passage is free you'll feel some air coming out the oil cap.

[Ilya]

Sorry for being dense, but we should make removing the timing cover part of regular maintenance? Isn't that...a tough job for a DIY mechanic?

No, look where the red arrow is. All you should need to do is pop the pump and apply air, the lifter won't even need to come out. If the passage is free you'll feel some air coming out the oil cap.

Ahh, understood. I imagine air in a can won't have enough oomph?

[VStar650CL]

If it's blocked, maybe Brakleen or Gumout, something with solvent and pressure. If it's open and simply being maintained, I'd imagine regular canned air would be fine.

[Ilya]

If it's blocked, maybe Brakleen or Gumout, something with solvent and pressure. If it's open and simply being maintained, I'd imagine regular canned air would be fine.

Good to know! Great stuff guys!