Brunner 2012 / A330 compressor - Need some help from the knowledgeable folks.

[Michael1107]

Greetings everyone,

I picked up this little gem on Craigslist for free.....the guy posted an ad for "scrap metal, and misc. equipment". I saw the compressor in the picture, and figured I'd get it, even with out knowing anything about it.

Turns out it an old Brunner....

I've been in touch with a very nice gentleman in Canada, at Atmosphair, and he's helped me with identifying the model, but he's not extremely knowledgeable on the internals.

I've already cleaned up the tank, flushed all the old **** out of it, fixed a few pin holes, and have it hydro tested. I'm going to clean up everything, and put a fresh coat of paint on it, but before I do, I need a little help with the pump itself.

When I removed the head, there was some oil residue coating the top of the piston, as well as the valve area. There is no scoring on the pistons, rings, or bores, and turning the crank slowly would create a strong suction that held for quite a while (almost a minute). Is it possible that the oil rings may not be sealing as well as the compression rings, which is allowing oil to get past, but still hold pressure & vacuum, or is some blow by allowed by design on these old pumps to lubricate the valve disc / springs?

The first pictures are how it looked when I got it home. The close ups are of the valve discs when I pulled the head off. The seats were pristine, but the discs had some wear. The groove is just deep enough to catch a fingernail on......can the discs be flipped over to the new side, or should they just be replaced?

As a side note, I've got quite a few pages of documents from Atmosphair on these old Brunners....if anyone needs some information, I'd be glad to share what was sent to me.

 

[Michael1107]

Here are the pictures of the valves.....does anyone know of a reason why they couldn't just be flipped over?

 

[Ridjobradi]

That's a good looking compressor. There doesn't appear to be any reason not to try. I would flip them and try it.

Sent from my SM-G900V using Tapatalk

 

[Michael1107]

Well, I flipped over the valve discs, and ran some tests with the compressor.

I'm getting a strong suction seal at the filter inlet, so it seems like the valve disc are sealing well. Pumping up from 0 to rated pressure is taking longer than the spec listed in the pages I was able to get from the Brunner manuals. In addition, I'm also getting some oil residue in the output line.

Normally, I'd say this indicates that the rings need to be replaced, but I'm not 100% certain. The crankcase oil level indicator was missing on the pump when I got it, so I have no good way to determine the correct fill level. Being overfilled would cause some blow by as well.

Does anyone have an A330, or Z500 pump in use, that still has the fluid level indicator? If so, could you post a picture from the side, showing the level and the crankcase in the same shot? I can estimate the proper fill level from the picture, and adjust mine accordingly.

If the oil level isn't the culprit, I'm going to order a set of replacement rings from Atmosphair. Is the 0.006" maximum clearance between the bore and piston rule of thumb the best approach for me to use when I hone the cylinders?

 

[mtu2000]

I have a similar compressor and am getting oil in the tank. I’m very curious if you replaced the rings and did that solve the problem? Also need the oil quantity if anyone ever figures that out!