Oil Accumulator Pressure Relief Valve Options

I am looking for options/opinions to deal with the pressure relief valve problem on my Accusump accumulator.

Problem needing solved: The pressure relief valve fails and I get a small leak from the valve and I want to find an alternative to the valve Canton provides.



The threaded end with the slot in it is staked in place and the stake fails allowing the threaded end to work its way out. When this happens, the pintle on the valve loses the spring preload and starts to leak. I have already replaced this once with another valve from Canton. The second valve has failed in the exact same manner. The valves they supply are Kingston KSV10H-2-175, set to relieve 175 PSI. The valve has 1/8" NPT threads and vents to atmosphere.

After talking with Canton about this again, their tech suggested I buy a replacement from McMaster to get a different brand. He said that he gets at least one call a day about this failure. A replacement is cheap, around $15. My concern is that if a valve were to come apart and I lose the seal completely, I will end up with oil dumping in my engine bay and on my exhaust system.

This leads me to thinking about the idea of having a vent to atmosphere relief valve in an engine bay is NOT a good idea, especially if the valves are notorious for failing. I started looking into other solutions, like an inline relief that I could plumb to a catch can. They exist, but I cannot find one that is 1/8" NPT with a 175 PSI rating.




I can find 1/4" NPT options, but I will need to take the accumulator apart and drill/tap the port for a larger size. This may be the way I have to go ultimately if I want to have an inline relief, unless someone could share their expertise.

In the meantime, I am going to order a new vent to atmosphere valve from McMaster and I am not sure what brand it is until it shows up. My thoughts are that for now I will probably add Loctite 290 at the threaded end and be careful not to get any on the pintle shaft.

Thoughts?

1/8" to -3 adapter, -3 hose, -3 bulkhead into catch can, convert to 1/8" npt so if it fails it would fill the catch can somewhere away from the belly and motor.

possibly use something like this remote mounted

This is different:

I don’t know if they make a hydrostat at 175 for propane but I can check. Same issue - it’s 1/4” NPT.

So the problem is the slot unscrewing...
Red loctite, or do a better job of staking it?
Run a 1/16" drill down those threads, then stake into that.

Seems easier than re-engineering the whole thing.

It'll still vent, but is that an actual problem?

There was some talk about this very thing in someone's build thread.
They put the PRV on the air side of the accumulator.

That seems like a stupid design though I'm not sure how it's setup. It have an air charge and some type of check valve so captures ~40psi oil off the engine's pump and opens if it drops

How is it possible to pressurize it over what the engine oil pump reliefs at? It'd blow the filter, cooler, etc.

Ok i read up on it.

Apparently their "patented pressure relief system" is nothing more that a $15 air compressor relief.

The claim if the piston fails it could fill the whole thing with oil and somehow overpresurize the oil side.

Two things I've always done with these
Check relief pressure
Seal with drop of epoxy (because I always had it)

I got burned a couple times and just started making it a part of my process.

I don't remember any that were the wrong pressure but I have changed the pressure to get me by in a pinch

subybaja said:

So the problem is the slot unscrewing...
Red loctite, or do a better job of staking it?
Run a 1/16" drill down those threads, then stake into that.

Seems easier than re-engineering the whole thing.

It'll still vent, but is that an actual problem?

Click to expand...

I agree with all of that. The vent to atmosphere isn't really an issue, just thinking about different options since I need to replace the valve at this point. It could be an issue if my oil pressure ever hit 175 PSI, but I don't see that happening... I like your idea of the 1/16" drill.

AKnate said:

That seems like a stupid design though I'm not sure how it's setup. It have an air charge and some type of check valve so captures ~40psi oil off the engine's pump and opens if it drops

How is it possible to pressurize it over what the engine oil pump reliefs at? It'd blow the filter, cooler, etc.

Click to expand...

I'm mowing what your growing and I don't fully understand how this is even needed. But its there and they designed it and I am keeping it for now.

rockmup said:

Two things I've always done with these
Check relief pressure
Seal with drop of epoxy (because I always had it)

I got burned a couple times and just started making it a part of my process.

I don't remember any that were the wrong pressure but I have changed the pressure to get me by in a pinch

Click to expand...

Have you had the same issue with the valve disassembling? What type of epoxy did you use?

Pressure vessels have to have a relief valve for legal reasons. Some 6” air tanks are considered pipe and don’t need valves.
You don’t need one for the system to work and they can’t tell you that.
In theory if the oil pump bypass broke and the pump generated high pressure which equals air pressure then venting the air is going to be replaced with high pressure oil until full and if it goes high enough the accumulator will leak or rupture. Air or oil you got problems. Most likely the oil pump system will break first.
Replace the leaking valve with a plug and only fill it with a ball pump. You only need around 15PSI.

abrogate said:

I agree with all of that. The vent to atmosphere isn't really an issue, just thinking about different options since I need to replace the valve at this point. It could be an issue if my oil pressure ever hit 175 PSI, but I don't see that happening... like your idea of the 1/16" drill.



I'm mowing what your growing and I don't fully understand how this is even needed. But its there and they designed it and I am keeping it for now.



Have you had the same issue with the valve disassembling? What type of epoxy did you use?

Click to expand...

I got a whole box of them that randomly unscrewed or had the pressures way off. Only time I've ever seen them unscrew but it was in a high vibration location. Somewhere else, they'd have stayed in place and never been an issue.
Wrong set pressures, i've sen that more than I care to admit.
They really are junk.