Another Injector Pop Tester DIY

[camboscams]

Hey, i have access to a standerd injector pop tester at work but it is designed for standard fractional style injector sizes... My question is what is the thread size on the vw injectors so i can get the right sized fitting

[Op-Ivy]

Where does the diesel enter this system?
Any pics showing that?

In the last picture, under the plate in the cylinder. Between the outer and inner cylinder. That is what you fill.

[anto]

Thanks op-ivy, its just i saw other pop testers with a reservoir built in, but i gather it doesnt matter and people only do that for ease of refilling.

[Op-Ivy]

I just took Andrew's idea and used a tranny fluid bottle. and filled it with clean diesel. Works great!

[anto]

Hopefully have mine working tonight all being well, il post a few pics once im happy with it....

Thanks,

Anton

[AudiVWguy]

Here's the one I recently finished. I got lucky on the gauge.
My injectors were suppose to be set to exactly 155 bar. But their not. (2050 to 2150 psi) 155 bar=2248 psi. Assuming this gauge is accurate (it was calabrated in 1987 then set on a shelf till I bought it on E-Bay)
Guess I'll buy some shims and play around.
Any Tips on cleaning, etc?

[anto]

Some pics of my DIY pop tester;





Just need to cut a hole in a jam jar top to contain the spray and diesel mist and im done.

[anto]

Just wondering should my tester be able to hold the pressure and not let it drop off in between strokes of the handle?

[jtanguay]

Just wondering should my tester be able to hold the pressure and not let it drop off in between strokes of the handle?

it would be best.  is the injector leaking at all?  you should be able to bring the pressure right up close to the breaking pressure and the injector should not leak.  i think theres even a small amount of time you're supposed to hold it at that pressure to make sure it doesn't leak/dribble.

[anto]

Injector doesnt leak, so its not losing pressure there, i think it must be the way i have made it, i just dont know whereabouts i have went wrong!?

[Vincent Waldon]

A couple of possibilities:

* the little one-way valve built into the base of your bottle jack is not holding the pressure.  Bottle jacks are pretty cheap and this happens sometimes... I'd probably just buy another one and swap out the welded parts with a new base.  Did the jack hold weight before you took it apart?

* you forgot to weld over the small bleed hole at the top of the ram tube... it's there to keep the ram from pushing out the top of the jack but will let out pressure when the jack is turned into a pop tester.

[anto]

A couple of possibilities:

* the little one-way valve built into the base of your bottle jack is not holding the pressure.  Bottle jacks are pretty cheap and this happens sometimes... I'd probably just buy another one and swap out the welded parts with a new base.  Did the jack hold weight before you took it apart?

* you forgot to weld over the small bleed hole at the top of the ram tube... it's there to keep the ram from pushing out the top of the jack but will let out pressure when the jack is turned into a pop tester.

Vince i welded over the little pinhole so i dont think it is losing pressure there.
However where you had a hole in the top large nut that could be welded, mine has a channel perpindicular to the threads, which i assume led to the pinhole.

Could this be where im losing pressure?

Thanks for the help guys, il get there in the end....

[smutts]

Just in case it is of use, for those who like playing with high pressure hydraulics in Devon,

 http://www.teignflex.co.uk/

They are lurking at Heathfield near Bovey Tracey just off the A38.

They do compression fittings for 6mm pipe and several hundred bar which is PROBABLY the right size for VW injection pipes, as well as for those weird BSPT fittings for pressure gauges, but Iwill let you know how I get on with mine.

Success! or amputation.

[gigaz2]

I figured a simpler way to do it:



I had the machinist make me a thread on the top nut, its 3/8", then an 3/8 to 1/2 adapter, then a 1/2 to male 1/4", then the T fitting.
also took a 1.9TD delivery valve to be cut into 1/4" thread (not seen done yet)

welded the pinch hole on the cylinder, used a M5x0,6mm bolt on the big nut.

enlarged the side hole on the external cylinder and fitted a 1/8" fittin and nut on the inside.

to do:
-filters (inlet and prior to the big nut)
-bracket for a cup and a small transparent hose
-jar with lid for keeping the diesel vapours out of my lungs
-use sealant on the threads and tighten everything down, if it leaks I'll weld it all around (simple weld compared to those shown)

[smutts]

Ok, I cheated. "Injection Tester" on Fleabay, for £80, so will save me a load of fagging about with a lathe, welding (JB of course ) and assorted taps and picking swarf out of my fingers. So I am now the proud owner of a Citroen Suspension Sphere Tester. DOH! Close, but definitely no cigar. Of to read the small print on Ebay.