Sumping Oil Pump Ball Check Seat Burnisher back-step

[Cotten]

Folks,

Sometimes when a new "better idea" comes along, it takes a while before we find out why it wasn't common practice all these years.

I have been evolving my sump ball-check burnishers in several ways, and even attempted to avoid compromise to the point of subbing out some of it to real live machinists and welders. Yet now, after tooling up to assure low cost as well as quality control by doing it all in-house, I find that the seats are not always concentric to the pump's threads.

No wonder my sloppy prototypes produced the best results.

Although I do not solicit folks to send me pumps, one presumed WLA body has presented genuine concerns with dressing techniques.
The casting was phenomenally hard, as if "chilled". It cut more like iron than steel... and believe me "cutting" was a last resort. Even stroking the gasket surface upon a stone made it "sing".

The pump arrived filthy, semi-polished and half-primered, and the bypass frosted in securely.
Upon cleaning, arthroscopic inspection revealed enormous pitting in the primary sump ball-check ('41 to '51 SVs had a secondary sump ball-check as well.)

CHKSEAT1.jpg

My diamond-dressed piloted stone quickly displayed the concentricity problem.
It was actually worse than the general pitting, but for one enormous crater right on the seat.

With nothing to lose, I spent time on fashioning a 29/64" counterboring endmill from drillrod to take the seat surface down from the top to produce a flat surface, and sharp edge to the gallery below for a place to dress the seat. At this point it became apparent that the gallery bore was several thou off center from my pilots.

Whether this is a WW2 fluke, or other models and vintages of H-Ds share problems, or even if some occasionally have been in a fire and then buried in mud before cleaned up for ebay,.... The application of burnishers has its cautions.
For as I attempted a go at it anyway, not only did the hard casting mar the burnisher badly,... it chipped the seat!
Ultimately the seat was refinished at the expense of another stone and burnisher, and some finesse, but lowered .060" in the process.

CHKSEAT2.jpg

After having applied my burnishers to a few dozen OHV pumps, a few 45" motors on the bench a decade ago, and a pre-'41-post-'51 pump or two in my reference drawers, slight marring of the burnisher's ball required many uses. Destroying one in a single use is an extreme example, but now calls for serious reconsideration.

....Cotten

[Huck]

Been wondering if somebody with tools and talent could bore the old seat out and rather than cutting a new seat, press in a new seat? I was playing with a swaglok fitting, they have a little backer rings for the ferrule that looked interesting.

[Cotten]

Huck!

Installing an insert would be three times the effort of just re-cutting whats there.

An insert would have to be installed at a heavy press to prevent seepage around it. This is the same problem I have encountered with petcocks.
Thus you must re-cut the insert's seat anyway.

The 45" pump brought two concerns to light:
Some pumps are cast from un-friendly material,..
and precision piloting from the cap threads is folly.

....Cotten

[FelthamW]

Cotten!!!
(always wanted to do that!)
From what you say, you want the pump body in hand because of this? I have two pump bodies that do it on two different bikes and was about to order that tool. Should I still attempt it and see if the burnisher shows eccentricity or just give up and wait until the motors come out of the frame? This "notice" is good timing for me.
Respectfully,
Wayne

[jibhead]

could you insert a seat cut from peek ?

[Cotten]

Wayne!

I have two of my latest production left,
and the chances of an OHV casting showing these problems are hopefully reduced,

But you may want to wait until I explore the techniques of allowing the burnishing ram to 'float' and accomodate off-center seats.

It is obvious that the complications possible,
with the literally hundreds of thousands of seats out there,
that performing burnishing upon an installed pump has its limitations, mostly of in-effectiveness, but in extreme cases, or in over-exuberant hands, it could cause harm.
A casting previously beaten with a drift may crack further.

Although in-chassis applications haven't resulted in harm so far, it is to be encouraged that pumps be treated on the bench, of course.

And Jib!

I have been approaching the same problem with petcocks, as I have been considering PEEK for the seat instead of the rod. But burnishing, the final step after all other cutting and grinding steps , isn't really applicable to the plastic.

Achieving a surface that needs little or no pressure to mate another surface closer than an oil molecule is wide.. is not easy. It is harder to achieve for PEEK than steel or iron, as the metals are much more finite. They don't move as much.

....Cotten