Air bubbles in the oil........

[widget]

If the seat in the oil regulator has overlapping impressions, it will allow air back flow.

Craig

Yes, I am starting to move in that direction as well now Craig. I chatted to an independant technician today here in Johannesburg and he also suggested it could be the regulator seat and spring, especially as we had some heavy fluctuations in the oil pressure previously, his theory was the spring and seat are getting tired and not sealing anymore (plus there may be overlapping grooves in the seat) thereby allowing air back into the sight glass and carrying the oil with it back to the sump.

..............and word from the field (the guys just called me) now is that under a magnifying glass there are distinct grooves in the ball.

So maybe we are homing in a bit here, but I still dont understand how air is getting to the ball in the first place.??
Any idea, is it harmfull to the unit?

 

[pescador775]

Widget, the only sources of bubbles are blowby or blowback and we now believe that the latter cannot occur. Even a new piston/sleeve will pass some gas (ahem) into the crankcase. With a bad seat, a portion of this gas is probably diverted into the channel leading from the regulator and into the bypass tube. For this to happen, I expect that as the 4th stg pressure builds some of the blowby is leaking back through the worn valve poppet ("ball" valve). The orifice on which the poppet is seated is probably sized to prevent this if everything is in order. That is, the total back pressure on the poppet will not lift the spring even at max delivery pressure. IOW, the spring pressure on the poppet is sufficient to prevent backflow. This is all negated if the seat is bad. IMHO

 

[CraigAClark]

If the regulator can't maintain constant pressure down stream (maintaining the "seal"), you will get back flow. If the machine is run long enough in this condition a loss of lubrication on the floating piston may cause damage to it. I'm curious, when the blow back occurs, is there fluctuation on the oil pressure gauge?

Craig

 

[pescador775]

I could be all wet on this but here goes; if the oil pressure is spec the spring might be OK. However, increasing the spring pressure on a bad seat will cause intermittant bursts of back flow of gas resulting in fluctuations bearing in mind that blowby gas pulses in synch with the piston.

 

[widget]

Blow back is only occuring at pressure above about 100-130 bar, if we keep a bleed open so pressure dosnt build, there is not air in the sight glass, so it stands to reason (or my reason anyway ) that air pressure is overcoming oil pressure somewhere.

But your theory Pescador makes sense,some of the air that is diverted into the return is overcoming seal pressure at around 120 bar, is that what you mean Pescador?? Sounds reasonable, but wouldnt that mean the spring is also a bit tired?

Cant remember if oil pressure changed when it started frothing Craig, I dont think we checked actually, at lower pressure before the bubbles start (ie) below 120bar the oil pressure is fairly steady at 6 megapascals.

I am just wondering why air takes the difficult route out (through the oil return) and not just straight out through the crank case?

If we wanted to test this "ball joint" theory, could we use any ball bearing of the same size, or is this a special type / coating etc, I dont really want to go buy a whole oil regulator kit, only to find its something else again.

I like Bauer products, but not that much.

 

[CraigAClark]

Hey Pesky,
If you look at the Capitano book, there is an exploded view of the regulator and oil circuit (don't know if you have seen it). The pump and regulator are the same as what is on the K14 and the oil circuit is the same principle, supply tube and return tube.

Bauer may or may not sell internal parts for the regulator, but I do know that if a part does not have a number, it isn't available except as an assembly. Older books will show
individual parts like connecting rods with part numbers, but you can only get them as part of the "running gear" assembly, the aren't sold individually.

Craig

 

[CraigAClark]

I am just wondering why air takes the difficult route out (through the oil return) and not just straight out through the crank case?

It gets to the inlet oil port, before it can reach the bottom of the piston on the compression stroke.

Craig

 

[widget]

Craig, could you just let me know on the "ball joint" theory, I edited it in on my previous post a bit late.?

Thanks man, I understand now the oil route story.

 

[pescador775]

Craig, yep, I noticed; I've been looking at the drawings.

 

[CraigAClark]

OK, here is a part number for a rebuild kit 072439. However it does not include a spring. Pesky the manual I have and the one you have of the Capitano, shows the older version of the regulator. The new one has the ball and carriage are now one piece.

Craig