F&#$ing pop tester...

[ghunt]

I must have bad luck or something.

I have a new set of uhaul injectors and IP waiting to go in my truck, and I want to get it done soon since fuel just keeps going up and up.

I figured I'd build an injector pop tester and test them myself.

First I bought a used 4 ton bottle jack. Put it all together and it wouldn't build pressure, instead when you pumped it it would just pump fuel back into the fuel reservoir.

OK fine, I guess I should have started with a new jack. So I bought a new 2 ton jack. Put it all together and #1, it won't hold pressure, and #2 there was fuel shooting out of pinholes where I welded the pipe coupling into the top of the jack (this is with it welded AND jbwelded). So I figure OK, I must have not done a good enough job. I run ANOTHER weld bead around it figuring it was probably getting up around the threads, then put on another good coat of JB weld.

So I refill it, start pumping it up, it still won't hold pressure and it's still shooting fuel out of pinholes in the same area.

God dammit, I give up. I've managed to waste $50 on something that won't even work. I should have just sent the ******* things out and had it done.

 

[jperecko]

in case you do try to approach the project again... be careful with those pinhole leaks - direct contact with your hand and you can get an injection of diesel or whatever you are pumping and you DO NOT want to deal with that type of injury

long story short, likely amputation

just be careful when dealing with anything high pressure - check for leaks with a piece of cardboard or something disposable and shield yourself from any potential high pressure spray

back to the project itself... I would grind down the welds that you have and clean up the surface really well so that you get a nice clean weld and you should be able to get it to hold pressure just fine
JB weld can work for lower pressure stuff but I would not rely on it for anything in hydraulic ranges

 

[icanfixall]

Your asking JB weld to handle 2000 lbs of pressure..... Its great stuff but its not going to handle that pressure. No epoxy will. Either grind it down and use brakeclean. Get all the oil out of the weld area and reweld it.... Or get another cheap pump and start over. But this time use brakeclean before you weld. What steel are you welding. Hopefully your not using galvanized pipe. You can not weld that unless you grind off all the plateing and thats really a tuff thing to do. Common black water pipe will weld fine. What rod are you using too. Stick rod 7018 works fine or 7024 mud rod will make a nice bead but it will not run uphill or around pipe. It has to be welded flat. 7024 is what the WWII ships were welded with. A 1/2 inch diameter rod about 3 ft long in a tripod. Strike it off and walk away. Start another rod on another weld.

 

[jperecko]

Your asking JB weld to handle 2000 lbs of pressure..... Its great stuff but its not going to handle that pressure. No epoxy will. Either grind it down and use brakeclean. Get all the oil out of the weld area and reweld it.... Or get another cheap pump and start over. But this time use brakeclean before you weld. What steel are you welding. Hopefully your not using galvanized pipe. You can not weld that unless you grind off all the plateing and thats really a tuff thing to do. Common black water pipe will weld fine. What rod are you using too. Stick rod 7018 works fine or 7024 mud rod will make a nice bead but it will not run uphill or around pipe. It has to be welded flat. 7024 is what the WWII ships were welded with. A 1/2 inch diameter rod about 3 ft long in a tripod. Strike it off and walk away. Start another rod on another weld.

good advice and one thing about brake cleaner... a great all around cleaner but just make sure it is not chlorinated or else it makes residue that turns into nastiness that can kill you when heated

 

[ghunt]

I'm just gonna have Russ do it. With some rapid pumping I could get it up to around 500 psi, but the pressure would fall right back off and fuel was shooting out of those pinholes anyway. I was using my mig welder, the bushing I welded in was forged steel and I had a good weld as far as I could tell. Bah I dunno what the problem was. I'm not putting any more money into this but I might see if I can make this one work eventually.

 

[Knuckledragger]

Maybe not even you. The bottle jacks now are all made in China with crappy metal and no qualtiy standards. You are probably welding on a sintered piece or a junky casting. Pinholes galore.

 

[hce]

The no weld solution

Fits inside a china 2 ton jack. Still need to drill the through hole. O-rings are low enough that they block the little hole on top.

 

[subway]

neat idea but you better pin the crap out of that or you have a large bullet ready to launch when the pressure builds.

calculate the area of that circle and multiply that by the psi you need to achieve plus a nice safety factor to get an idea on the force that thing can make.

not trying to flame i just saw that and i dont want anyone getting hurt.

 

[jperecko]

neat idea but you better pin the crap out of that or you have a large bullet ready to launch when the pressure builds.

calculate the area of that circle and multiply that by the psi you need to achieve plus a nice safety factor to get an idea on the force that thing can make.

not trying to flame i just saw that and i dont want anyone getting hurt.

guess we turned this into a hydraulic safety thread... oops


actually fluids do not store energy like gas or air does... so even if whatever was securing it was to fail, it should just kinda nudge up a little

 

[david_lee]

about the pressure leak-down, remove the top nut that you welded the pipe coupling into. have a look at the threads on the nut from the inside. odds are that there is a flat cut into the threads.

i believe this is done to allow any air or fluid between the pressure (lower) seal on the shaft and the wiper (upper) seal on the nut to flow out from between the seals and avoid a pressure buildup as the shaft rises.

i used jb weld to seal that relief slot on mine. the tube that the nut screws onto should also screw into the base plate (essential quality for sealing the nut). i did it by
1. measuring the assembled height
2. removing the nut and reservior can
3. scribing a line in the pipe and base to mark their current alignment
4. put the base in a vise and take the pipe loose
5. set the pipe at 1/4 turn from original location (allows for inconsistentcies in the next step)
6. screw the nut on the pipe, without the reservior can, to the assembled height measurement
7. scribe a line on the nut and pipe to mark proper alignment (incase you accidentally move it)
8. remove pipe and nut together
9. apply jb weld and allow to sit and harden for 24 hours (i then put mine in the oven for 6 hours on lowest setting to make sure that the jb weld had cured to the fullest)
10. reassemble with reservior can
11. leak-down fixed

you should grind down your welds, clean it all up, and reweld it before sealing the threads cuz i dont know how the jb weld would like the heat from the welding

 

[ghunt]

So why not just weld that top nut onto the tube? I suppose i might try that as well...I dunno. Haven't heard from Russ yet, I guess he's not around today.

And no JBweld doesn't like being welded around, it's only good to 300 degrees. It gets soft and crumbles.

 

[typ4]

Got your pm, I will be gone for 2 weeks at the job, so the turn around wouldnt be good. No charge just to pop them.

 

[david_lee]

Welding it would work too, but I didn't trust my welding skills enough to be sure that I wouldn't warp the tube or burn a hole in it

 

[david_lee]

Also, I forgot that I loosened the nut one full turn, then applied the jb weld and retightened the nut back to the alignment marks

 

[ghunt]

Got your pm, I will be gone for 2 weeks at the job, so the turn around wouldnt be good. No charge just to pop them.

Well actually that is probably alright because I might get to them Easter weekend at best. What day will you actually be back and how long would they take to test? Also I wanted to balance them, if I wasn't clear on that.

Ahh, I might mess with my pump again and see if I can make it work.