XYZER Hollow Dipper failures out there?

[XYZER]

Has anyone out there had a hollow dipper failure out there?? I have never had any negative feedback from anyone. There are maybe 75-100 out there. If anyone has had an issue jump in and let me know.
Dave

[Rom]

None here thus far Xyzer. 3 of your converted 3inch to standard size units doing exactly as they should thus far.

Rom

[akghound]

I broke one when I was taking off a rod cap. Hit it with the ratchet handle when the nut came loose. Definitely not the fault of the dipper, just the dummy on the end of the wrench. Point is ..... remove the dipper before removing the rod cap. I think they are a very good deal.
Ken Gardner

[cujet]

I don't have many hours on my XYZer drilled dippers. However, Bruce runs his twin hard and so far, so good.

Are you expecting problems? Are they brittle?

[sailawayrb]

Nope, no failure yet and none expected.  A great product and I only wish rest of engine was of similar quality.

[mobile_bob]

Sailaway:

"i only wish my engine was of similar quality..."


PUUUUULLLLLEEEEEEEEEEZZZZZEEEEEEE!!!

i have seen pictures of your work, and if your crankcase was large enough for the requisite crew and tooling
i would rather have brain surgery there as any operating room on the planet!

your attention to detail is second to none in my opinion!



come on Bob, you can tell us, you deburred and polished your xyzer hollow dipper before you installed it didn't you?

lmao

bob g

[XYZER]

I don't have many hours on my XYZer drilled dippers. However, Bruce runs his twin hard and so far, so good.

Are you expecting problems? Are they brittle?

Here is the scoop so far.... A fellow Listeroid off grid user has logged more than 8000 hours on 2 engines and had the dipper fail on both engines around the same time. The exact reason is unknown. They broke flush with the rod cap. I would recommend making sure the jam nut is not over tightened and to dispel the fears of it coming loose maybe loctite it.

I broke one when I was taking off a rod cap. Hit it with the ratchet handle when the nut came loose. Definitely not the fault of the dipper, just the dummy on the end of the wrench. Point is ..... remove the dipper before removing the rod cap. I think they are a very good deal.
Ken Gardner

Hey Ken how far did it bend before it broke......or did it just snap off? How may hours do you have on your twin now?

I have some 3" dippers I can perform a destructive test on and see how far it will bend before it breaks.

That is all I know at this time.....if I learn more you all will be the first to know!
Dave

[Halfcrazy]

[/quote]

Here is the scoop so far.... A fellow Listeroid off grid user has logged more than 8000 hours on 2 engines and had the dipper fail on both engines around the same time. The exact reason is unknown. They broke flush with the rod cap.


[/quote]

It seems suspicious that 2 engines had the same issue at the same time. This would lead me to believe it was related to the engine or owner not the product? maybe he torqued them in way tighter then he should have?

[Crofter]

breaking at the cap to nut level seems strange. I would have thought any fatigue induced by striking the oil repeatedly would have created the fracture at the unsupported side of the nut.

I think that a torque load that puts the available material near the limit of the elastic stretch, and just shy of the permanent yield point, would be the best bet.  Having the hole's area become part of the equation would reduce the actual amount of torque required to pre load the remaining material to that level.

[Crumpite]

Sounds a lot like overtorqueing the holding nut.

It's just possible that some type of stress corrosion is happening.
What type of steel are they made from, if it's not a secret ?
Any leaded steel might be suspect...

Daryl

[JohnF]

OK;

Tried to stay out of this but the ever-present and omnipotent "second guessers" have made me contribute.  It was my engines, and no, they did NOT both fail at the same time.  The bolts were NOT over-torqued and the break was at the bottom of the nut.  The engines had over 8k on each using XYZer's dippers and it is my suspicion that the constant shock wave of the broad edge of the dipper hitting the oil is causing a stress fracture.  There are three possible reasons - the hole is too large leaving not enough material to withstand the constant impact, the metal is not strong enough or the flat edge of the dippers are just providing too much resistance.  But, of course, anyone out there with more experience than me with long running engines feel free to chime in anytime.

Nothing here is an indictment of XYZer's work - his dippers are very nice but there COULD be a problem in long running engines that was not anticipate in the original design - BUT, it is an absolute need to know.  I have sent the second broken dipper back to Dave for analysis.

[Crofter]

So far it seems that we are all guessing at this stage; It seems now that there isn't agreement about exactly where the breaks occurred on the dippers: above the nut or below the nut has different implications. I tend to agree with John's thought about flexing from hitting the oil if they break below the nut.

[mobile_bob]

Hotater and I discussed this issue a few years back, when we were talking about
an accumulator style dipper that included a filter.

at that time i was concerned with the strength of the bolt used, and we decided if it was to
go through we ought to drill and tap the rod cap for 3/8" NF and use a grade 8 bolt for the material

when you figure the dipper being 5/16" stock and the minor diameter of the thread being well under that
and then have an 1/8" hole up the center, it just doesn't leave much material. the sharp V bottom thread
makes for a natural stress riser and a great place for a crack to start was the concern.

never discussed these concerns on the open forum, because it appeared that there was nothing to worry
about, even now there would seem to be little to be concerned with as there are so few failures?

at this point perhaps an upgrade to a larger bolt or stock for the dipper might be something to think about?

also one could use a flanged nut for the jamb nut, placing the jamb nut on backwards so that it could seat against
the rodcap and provide a better support than a standard nut.

then there is this, it might be the tapped hole is not perpendicular to the face of the rod cap, so when you torque down
it places a side load/bending to the dipper, if this is so (as i suspect it is given the likelihood that an indian with a hand held drill
might well have been the method used to make the hole before being hand tapped?

more little details to check out i guess.

one would think it more likely that there is a simple explanation for the one occurrance, because if there were a fault in the dipper
i would expect far more reports of failures.

bob g

[Crofter]

312,000,000 revolutions in 8000 hours but if the end of the dipper is being induced to its resonant vibration frequency like the tine of a tuning fork then the number of stressing cycles could actually be hundreds of times higher than the revolution count.

I have seen unloaded projecting members fail from vibration that certainly weren't lacking in brute strength. High pressure injection lines are a prime example and they can sometimes be seen buzzing.

[JohnF]

There are not may people out there that put on the hours I do so I would expect very few reports of broken dippers.  I'll wait for Dave's report, it does look to me like a stress fracture - but I'm not a metallurgist.  The problem, of course, is that there is no warning that a dipper has broken and it doesn't take very long for the big end bearing to melt, that is why I'd like to get to understand what has happened.  I may try drilling a standard dipper but the hole will be much smaller, how much is enough when we are talking of oil getting to the bearing?  If "knife edge" is enough to throw oil up under the piston, then enough drips back down through the top weep holes into the bearing, I suspect I won't need much being forced up from the bottom