Injector balancing: Shady Tree Mech. style

[coachgeo]

Started this thread so not to hi-jack another one.

Seems you need a pop tester and lots of different thickness washers and other parts.

below is a few post coppied over to this one for reference.

[coachgeo]

Originally posted by coachgeo
How do you adjust them and what is being adjusted" Is pop pressure being equalized between each injector? I assume so. Does one adjust them by the size of the washer that sits on the spring inside the injector ?

Originally posted by TomJ
Yes, pop pressure is being equalized in the set, good way to put it.

Yes, adjusted by washer thickness that sits on the spring.

For those who have bought one of these ebay pop testers, you can also switch and swap housings and springs to come up with the bar you are shooting for if you don't have a wide selection of shim washer thicknesses.

[coachgeo]

HERE is a picture of a pop testor. Sorry I cant just put the pic here. Apparently you cant use an [img] link to a file that already exist on this forum. Sounds like a dumb way to write the coding but that's how it is.

[coachgeo]

Originally posted by TomJ
....For those who have bought one of these ebay pop testers, you can also switch and swap housings and ....

Housings? How do these differ enough to change Pop pressure?

[phantoms]

Here's a good looking injector tester. Haven't inquired as to price though.

http://www.toolgate.com/det05.html

[jbaj007]

"Here's a good looking injector tester."

A real shade tree mechanic makes his own
Here's mine, made from a bottle jack.

[Benzcrusher]

OOH, do tell how you made that tester!!! That is right up my alley....

[jbaj007]

I used a small bottle jack (Craftsman 2 ton, I think) and removed the top nut (really torqued on there!!!).

Take apart the cylinder of the jack and remove the center rod and seals (like on a master cylinder).

There is an inner cylinder, that the center rod was in, that is the pressure chamber of the jack and there is a small hole near the top of this inner cylinder. Seal that little hole (weld it or I just used JB Weld).

Drill or grind out the hole in the top nut where the center rod passed thru and tap it for a bushing (mine was 3/4 NPT, I believe).

From there it's a matter of some plumbing fittings and an old injector line. The metric adapter to mate up with the other copper fittings and to the injector line was difficult to find; I can't remember if I had to do a little "thread adjustment" with die and tap to go from pipe thread to metric. It takes a little finagling, but, if I can do it, you can, for sure. FWIW


Edit: I think this is where I found the metric/NPT adapter (at least it was in my "Favorites" folder for something):http://www.fittingsandadapters.com/metric.html

[Old300D]

Originally Posted by jbaj007

I used a small bottle jack (Craftsman 2 ton, I think) and removed the top nut (really torqued on there!!!).

Take apart the cylinder of the jack and remove the center rod and seals (like on a master cylinder).

There is an inner cylinder, that the center rod was in, that is the pressure chamber of the jack and there is a small hole near the top of this inner cylinder. Seal that little hole (weld it or I just used JB Weld).

Drill or grind out the hole in the top nut where the center rod passed thru and tap it for a bushing (mine was 3/4 NPT, I believe).

From there it's a matter of some plumbing fittings and an old injector line. The metric adapter to mate up with the other copper fittings and to the injector line was difficult to find; I can't remember if I had to do a little "thread adjustment" with die and tap to go from pipe thread to metric. It takes a little finagling, but, if I can do it, you can, for sure. FWIW


Edit: I think this is where I found the metric/NPT adapter (at least it was in my "Favorites" folder for something):http://www.fittingsandadapters.com/metric.html

I want to thank you for your valuable contribution. I built myself a diesel injector tester very much like the one you describe here and it works brilliantly!

I tapped the bottle jack for 3/4" NPT, and JB welded the bushing in, as there was not much thread. I also JB welded the setscrew I tapped into the pressure relief hole in the cylinder. For adapting the MB injector line to the standard plumbing, I used a 1/8" NPT to 6mm OD metric compression fitting on a sawed-in-two line - no thread adaptation necessary! I have a complete parts list from McMaster-Carr if anyone is interested - the total bill was less than $60.

I tested a set of used NA31x injectors with a fluid mix of ATF and Marvel Mystery oil - had good spray patterns, nice popping, and as far as I can tell, consistant pressure relief at 1850-1900 psi.

[phantoms]

The one thing I've noticed with all three of these (and others I've seen in the past), is that it seems it would be hard to get an injector within a couple bar of each other since the scale is usually in 10 bar or more.

[BoostnBenz]

Isn't factory spec 5bar? If it is broken into 100psi increments that is a little over 6 bar per increment so you pretty much have to hit the same area between the two at once.

Nice creative work jba, I think I'll bookmark this page for future reference.

[phantoms]

Originally posted by phantoms
Here's a good looking injector tester. Haven't inquired as to price though.

http://www.toolgate.com/det05.html

They moved the page to http://www.toolgate.com/index_files/dit.htm


I've sent a e-mail requesting the price.

[Old300D]

Does it matter what fluid you use in the DIY tester? Does it have to be bled before testing an injector? Excellent idea there BTW.

[jbaj007]

Bosch specifies a special test fluid for their testers.

I use Mazola oil.

It bleeds itself after a few hearty pumps of the handle.

[phantoms]

I would imagine diesel itself would work well and give an accurate indication of the injector.