Quote:
Originally Posted by BillGrissom
I went back to my post http://www.peachparts.com/shopforum/diesel-discussion/346142-electronic-pop-tester-cheap.html
Your question was about finding McMaster-Carr PN 5269K311 Metric fitting, 1/8" NPT-M to 6mm tube ($4.11)
I opened their website today, entered PN and below showed. That fitting is critical in fab'ing any custom pop tester since the M-B injector tube attaches to it (same fitting as M-B Delivery Valve). I read where some people machined their own. Somewhere (VW TDI site?), I saw reference to the fitting description and that someone bought one from McMaster, so searched and found it. While on the site, lookup the PN's I used for injector shims.
Correct that I didn't notice a difference in the idle from when it had 3 1600 psi and 2 1950 psi injectors in the 1984 300D. Of course, hard to compare then and now. It does idle fairly smooth now, perhaps slightly better but I don't recall significant shaking before, though the air cleaner danced then and now.
Your videos of the pressure gage needle and spray are similar to my results, (and most on youtube). It is hard to resolve better than 50 psi with the gage needle. One might get more consistent results with a gage with a "peak grabber" needle. I added an electronic pressure sensor to try to get better resolution, but even then the results vary a bit with the way the handle is pumped. I found that if I didn't press hard enough (I think), I could sometimes get a continuous spray from an injector instead of pops. Faster strokes tended to give more consistent results, and is probably closer to the real engine. I would get ~10 pops from one stroke of the handle, coming much faster than in your video. |
Thanks for the info Bill, I searched 5269K311 McMaster just now and found it no issue. Their search engine must have been down the other day (searching exactly the same way).
I made a custom fitting for the adapter between injector to the pop tester by using a broken 1/4" NPT pressure gauge brass block, cut in half, drilled and tapped for the 6mm injector hard line cut in half, threaded the end with a die, screwed into the brass block then either brazed or silver soldered it. It's workin fine so far. Lot's of DIY pop tester articles says to use all steel fittings, not brass. The gauge that you are using has a brass NPT base (similar to what I used except I used the next size 1/4 NPT, heftier than 1/8 NPT) so I think I should be OK?
To see the gauge needle better I may try using a borescope magnified on a PC and see if that helps.
Took the car for a spin and wow, big improvement in power! There was a lot of traffic, no room to do a 0-60 timed run. I do have a leak on #4 maybe #5 injectors coming from either the return nipples or the injector flare...will have to isolate which. I need to buy some braided return lines to replace those clear (now browned) Tygon polyurethane return lines which are 1.5 years old and in my experience will fail soon.