My Rix SA-6 Diesel

[rob.mwpropane]

Just a quick update. Topped off 6 tanks today, took 57 minutes. 4 HP 100 pumped to 3600, 2 of which had less than 1000psi and then 2 AL 80's pumped to 3100. Can't tell you how ecstatic I am to be able to do this. I'm like a little kid on Christmas.

Quick question to you veterans, what is your shutdown procedure? Do you open the bleeders then shutdown or wait until off and then bleed down? I'm thinking to open the bleeders then shut the engine off..

 

[grf88]

I shutdown and then bleed off.

 

[G Ellis]

For both the SA-6 and SA-3

1. Rock from side to side the rod end casing at 3 position TDC, centre line and BDC on each of the 3 stages.
2. If the rod end metal casing is clear of the swash plate metal housing your OK
3. If its not and metal touches metal then you need to replace the pins. (two for each stage)

If all you want is a tighter tollerance or "rock" angle then simply remove the rod end bolt, pull out the 2 guide pins and reverse the plastic guide pin rods so a new "face" is showing.

Now if you then find that the other end has been used already and shows heavy wear grooves or an angled scuff, then you need to replace the pins with new.

The guide pins are made from a simple 1/4" rod, its the specific plastic polymer material that's the expensive part at $9 each and I can't offer a cheaper alternative such as delrin, co polymer acetal or POM. All of which would work to a point but life expectancy would be greatly reduced and the consequence of snapping off a con rod is an expensive risk. Iain.

I am tipping these pins are either a polyimide (not amide) or PEEK.

 

[rob.mwpropane]

I am tipping these pins are either a polyimide (not amide) or PEEK.

Mine have not gone past the minimum amount of play so I won't be changing them.

 

[iain/hsm]

I didn't know you worked for the magazine also

Well it's good it's the 2nd and not the 3rd I guess. Is there any chance that this can work itself out? It seems to be getting to be less and less of a leak... I don't know, wishful thinking maybe?

Edit: just went back and looked, sure enough it's the 2nd stage.

I work with the sweat of my brow for who ever wants to pay me I'm not that fussy. But thanks for the magazine suggestion. Now as for "this can work itself out" nonsense that my friend is the sort of junk advice that belongs in a womans magazine. Hope dies last with the wishful thinking.

If you can't hear it leaking anymore there is a simple answer: You've gone deaf with the noise its been making.
Take it out inspect the rings and replace the o-ring if required.

Now you do have one advantage if you still have that 2nd stage pressure gauge fitted, check the interstage pressure
while running.

1st group in barg and psi line is at FINAL PRESSURE
2nd group is 2ND STAGE @ SEA LEVEL
3rd group is 2ND STAGE @ 1500 M 5000 FT ELAVATION
Done in BARG and PSIG just to confuse the heck out of everyone

137 barg / 2000 psig 29.3-32.7 barg /425-475 psig 26.8-30.3 barg /390-440 psig
172 barg / 2500 psig 31.0-34.4 barg /450-500 psig 28.9-32.4 barg /420-470 psig
207 barg / 3000 psig 32.7-36.2 barg /475-525 psig 31.0-34.4 barg /450-500 psig
241 barg / 3500 psig 34.4-37.9 barg /500-550 psig 33.1-36.5 barg /480-530 psig
275 barg / 4000 psig 37.2-41.3 barg /540-600 psig 35.8-39.3 barg /520-570 psig
344 barg / 5000 psig 40.0-44.8 barg /580-650 psig 37.9-42.7 barg /550-620 psig

Low pressure will be caused by one or more of the following:
Worn 1st or 2nd stage piston rings.
Leaking 1st stage valves.
Broken 1st stage head gasket.
Leaks in piping or 0-rings.
High 1st stage piston clearances.
Restricted inlet hose or filter.

High pressure will be caused by one or more of the following:
Leaking 3rd stage valves back into the
Worn 3rd stage rings.

Warning: Running the compressor for long periods with low interstage pressure may cause
overheating of the 3rd stage resulting in reduced ring life and probable 3rd stage 0-ring failure. Your call,

 

[rob.mwpropane]

I work with the sweat of my brow for who ever wants to pay me I'm not that fussy. But thanks for the magazine suggestion. Now as for "this can work itself out" nonsense that my friend is the sort of junk advice that belongs in a womans magazine. Hope dies last with the wishful thinking.

If you can't hear it leaking anymore there is a simple answer: You've gone deaf with the noise its been making.
Take it out inspect the rings and replace the o-ring if required.

Now you do have one advantage if you still have that 2nd stage pressure gauge fitted, check the interstage pressure
while running.

1st group in barg and psi line is at FINAL PRESSURE
2nd group is 2ND STAGE @ SEA LEVEL
3rd group is 2ND STAGE @ 1500 M 5000 FT ELAVATION
Done in BARG and PSIG just to confuse the heck out of everyone

137 barg / 2000 psig 29.3-32.7 barg /425-475 psig 26.8-30.3 barg /390-440 psig
172 barg / 2500 psig 31.0-34.4 barg /450-500 psig 28.9-32.4 barg /420-470 psig
207 barg / 3000 psig 32.7-36.2 barg /475-525 psig 31.0-34.4 barg /450-500 psig
241 barg / 3500 psig 34.4-37.9 barg /500-550 psig 33.1-36.5 barg /480-530 psig
275 barg / 4000 psig 37.2-41.3 barg /540-600 psig 35.8-39.3 barg /520-570 psig
344 barg / 5000 psig 40.0-44.8 barg /580-650 psig 37.9-42.7 barg /550-620 psig

Low pressure will be caused by one or more of the following:
Worn 1st or 2nd stage piston rings.
Leaking 1st stage valves.
Broken 1st stage head gasket.
Leaks in piping or 0-rings.
High 1st stage piston clearances.
Restricted inlet hose or filter.

High pressure will be caused by one or more of the following:
Leaking 3rd stage valves back into the
Worn 3rd stage rings.

Warning: Running the compressor for long periods with low interstage pressure may cause
overheating of the 3rd stage resulting in reduced ring life and probable 3rd stage 0-ring failure. Your call,

Thanks for that Ian.

I do have the gauge still installed. If memory serves me correct my pressures are right on the money. I topped off 6 tanks today and kept an eye on everything. Those fall right in line with what I was seeing.

As far as the "blow by" coming from the piston, it's still audible. It's not as much as it was in the very beginning, but it's something that needs to be fixed.

 

[iain/hsm]

Everything was going great until around 2200 psi or so I heard a pop and a hiss. Sure enough a BSP to NPT fitting cracked.

And that's what happens when you buy cheap junk designed for hydraulic applications using scrap metal made in China. And why when any "Frankenstein" compressor build that enters our workshop the first thing we do is work out what parts may end up flying accross the place at the 5000psi test pressure and rip them out.

A quality build compressor will have the makers name on every tube fitting part used and if in doub you can look up the fitting catalogue and find out the design working pressure and burst pressure under a 4: 1 ratio for high pressure pnumatics.

BSP and BSPP fittings on the other hand in Europe are by and large used on low pressure 10 bar 150psi applications
and higher but on static hydraulic applications with a 3:1 ration so looking on the bright side you did pretty well on that 2200 psi burst but never too late to suggest in future use Swagelok.

 

[iain/hsm]

I am tipping these pins are either a polyimide (not amide) or PEEK.

And they are not. Now although I know exactly what material is used for every single component on these compressors but deliberately chose not to disclose certain technical or engineering aspects on an open forum for obvious reasons.

Now while I may choose to offer some mild commercial alternatives to the original Mil-Spec items to make things easier for second time users by way of cheaper cost or ease of availability IMHO it doesn’t help making a guess at the actual material used for a small but important component like the rod end pin that in the event of a premature failure would cause extensive and very expensive damage to the back of the block or piston barrel or liner.

Reason is loosing a home made cheap plastic pin alternative to the original nine dollar rod end pin while running at 1500RPM will at best snap the con rod to save the more expensive rod end bearing. The snapped con rod will now depending where it snaps could be free to smash around the back end of the block or inside the piston liner. Both options are repairable but not recommended. Now I guess you could always bank on switching the thing off quick but with a con rod stump jabbing about at the back end of the block at 25 jabs a second its going to be over before you can blink. All for a $9 part that you can use again by poking out the other end when its done all for $9 dollars.
With an answer like that my talents are wasted in design engineering I should be in sales. LOL

 

[G Ellis]

And they are not. Now although I know exactly what material is used for every single component on these compressors but deliberately chose not to disclose certain technical or engineering aspects on an open forum for obvious reasons.

Now while I may choose to offer some mild commercial alternatives to the original Mil-Spec items to make things easier for second time users by way of cheaper cost or ease of availability IMHO it doesn’t help making a guess at the actual material used for a small but important component like the rod end pin that in the event of a premature failure would cause extensive and very expensive damage to the back of the block or piston barrel or liner.

Reason is loosing a home made cheap plastic pin alternative to the original nine dollar rod end pin while running at 1500RPM will at best snap the con rod to save the more expensive rod end bearing. The snapped con rod will now depending where it snaps could be free to smash around the back end of the block or inside the piston liner. Both options are repairable but not recommended. Now I guess you could always bank on switching the thing off quick but with a con rod stump jabbing about at the back end of the block at 25 jabs a second its going to be over before you can blink. All for a $9 part that you can use again by poking out the other end when its done all for $9 dollars.
With an answer like that my talents are wasted in design engineering I should be in sales. LOL

Hi Iain, yep, some good points. I recently bought a compressor from the same guy as rob.mwpropane and some numpty has not put the shim back on the first stage rod end and run the compressor which has chewed out the pins which means they can't be reversed. Until everything is good I will not be running this compressor. In Australia the $9 pins are $20 each (say $25 aussie each). Speaking of sales, if you can sell spare parts for these compressors I would be happy to be a customer. BTW, Vespel plastic is not cheap at about US$ 55 per inch.

 

[rob.mwpropane]

Hi Iain, yep, some good points. I recently bought a compressor from the same guy as rob.mwpropane and some numpty has not put the shim back on the first stage rod end and run the compressor which has chewed out the pins which means they can't be reversed. Until everything is good I will not be running this compressor. In Australia the $9 pins are $20 each (say $25 aussie each). Speaking of sales, if you can sell spare parts for these compressors I would be happy to be a customer. BTW, Vespel plastic is not cheap at about US$ 55 per inch.

Very sorry about your situation. Since it's just the 1st stage can you buy just those 2 pins to get back up and running? I'm not sure what part you're talking about, the shim?