Lap, lap, lap your seats, under the diesel spring...

[Turbinepowered]

Soooooooo... lapping these injector nozzle seats blows.

The car the engine came out of had 150k+ miles on it... and I think these were the original nozzles. If they were ever replaced, I don't think these sealing surfaces were lapped.

I've taken a shim increment's height off one of these! .06mm, and the gouges in the nozzle sealing surface still aren't gone! I'm still on 200 grit sandpaper and light oil, working on a glass tabletop.

One of them is looking nice, though. 200, 400, and 660 grit sandpaper, and she's nice and clean and shiny as a mirror.

[Turbinepowered]

Oh, and, as a question for Vince and others who have done this... how long does it usually take for you guys to do the lapping per injector?

It's really only the nozzle sealing surface that's giving me crap. The injector halves lap nicely, and their respective seat sealing surface is a piece of cake too. Just that nozzle seat...   :x

[subsonic]

You are not alone, I did a set and it took a long time to get rid of the grooves. Longer then I thought it would.  Be careful you dont loose patience and start giving it some to get it done quicker.  I did and ended up with 2 that were not perfectly flat.  Ie.. leaking.  I suggest setting up infront of the tv with a six pack, throw in a movie and away you go.

[Vincent Waldon]

Oh, and, as a question for Vince and others who have done this... how long does it usually take for you guys to do the lapping per injector?

It's really only the nozzle sealing surface that's giving me crap. The injector halves lap nicely, and their respective seat sealing surface is a piece of cake too. Just that nozzle seat...   :x

My recommendation would be "easy does it"... a quick pass with the rougher sandpaper and then most of the time (maybe a minute ?) on the 600 (or even finer if you can get it.).   I found a supplier of 1000 and 2000 and that's what I'm using these days.  I also tend to skip the rough paper if there are no visible wear marks on the sealing surfaces, and head straight to polish.

I actually found a 4000 abrasive bar that I use as a final polish.. as I understand the official Bosch procedure that's about the grade they use to do their polish as well.  No doubt the entire thought of using sandpaper makes Bosch-trained folks shudder... but it seems to work.. again, easy does it !!

[Mark(The Miser)UK]

Just been experimenting with some injectors. Cleaning the carbon off I've found an oven cleaner foam softens quickly and can be wiped off.
On one I decided to lap the pintle. Under an eyeglass the trailing edge of the seal was pitted.
 
I used some ancient valve lapping paste [fine paste side] I dabbed some on the tip, reinserted carefully into nozzle and used a small hand drill to rotate oiled pintle removed /cleaned etc  and reassembled. It did seem to work. Inspecting seating area it did look a little grooved, but that may disappear after use.

When increasing break pressure, I'm unclear why there is talk of lapping several different parts. The only part that needs lapping is the top half of the injector. this is easily done with one of those cheap diamond impregnated wood chisel sharpening stones.

 The more faces you try to lap, the more chance of loosing parallel mating and then forcing to mate the surfaces, binds up the pintle IMO
If things are mating properly then injector body shouldn't leak with maybe 15lb ft torque. [Increase when happy with setup.]
 If  there is a leak then disassemble and use permanant black felt tip to find leak

[blkboostedtruck]

Ha Ha Turbinepowered! it's not as easy as it seems! my finger's ach just thinking about it!
i actually hate doing them now! buying this poptester i realize was not such a great idea after all !
you still sending them to me to poptest or did you make up your own rig?
Duane

[Turbinepowered]

My recommendation would be "easy does it"... a quick pass with the rougher sandpaper and then most of the time (maybe a minute ?) on the 600 (or even finer if you can get it.).   I found a supplier of 1000 and 2000 and that's what I'm using these days.  I also tend to skip the rough paper if there are no visible wear marks on the sealing surfaces, and head straight to polish.

I'm not bearing down on it at all, just the weight of my finger in a circular motion; I don't want to cut more grooves in the thing. The problem is all my "wear marks" are quite deep, concentric circles that match up with the top of the nozzle. They aren't uniformly deep, they're almost gone directly under the fuel ports, but the arcs between those ports are still visible, and I still hang up when I draw a fingernail lightly across them.

I actually found a 4000 abrasive bar that I use as a final polish.. as I understand the official Bosch procedure that's about the grade they use to do their polish as well.  No doubt the entire thought of using sandpaper makes Bosch-trained folks shudder... but it seems to work.. again, easy does it !!

So reaching for the 3k grit stone wouldn't be a bad idea for the final? I imagine using a bottle-jack based pop tester makes them shudder, too, but I am clean with this process.

[Turbinepowered]

Ha Ha Turbinepowered! it's not as easy as it seems! my finger's ach just thinking about it!
i actually hate doing them now! buying this poptester i realize was not such a great idea after all !
you still sending them to me to poptest or did you make up your own rig?
Duane

I finally found the leak, so I've got them covered. Missed an entire bleeder port, eeesh.  :roll:

I keep coming home from work (12.5 mile bike trip at 3AM, nice ride), having a sandwich, then sitting down at my glass table with the radio on to lap a seat.

[Duster 5.9]

what are you guy's talking about? are there any pic's or vid's in the archive's? on what your really doing?

[Vincent Waldon]

Yeah, it's a bit obtuse, isn't it.

We're talking about "lapping", one of the steps needed when rebuilding injectors:

http://vincewaldon.com/index.php?option=com_content&task=view&id=20&Itemid=28

[commuter boy]

Hey Vince, you're famous!  

I had a set of newish nozzles swapped into the 1.9 bodies from the 1.6 ones that came with the umwelt AAZ Passats and the Bosch guy mentioned that he had an increasing amount of injectors show up at his shop "because some guy put a DIY page up in the internet and now all these people are screwing up their injectors and showing up at my shop with "rebuilt" injectors that need to get cleaned, re-done, shimmed and pop tested to work properly."

He wanted to thank you for all the extra work you're sending his way  

[burn_your_money]

LOL

[Vincent Waldon]

That's actually my secret evil plan to keep the remaining diesel shops in business.

You're welcome, Giles !!!   ;-)



Vince

[blkboostedtruck]

He! He! thats funny! and that means mine that i have done are good even the one's i did for my self! so either that means i know how to read? or i'm just brilliant and luckey ? but i could not have done it with out Vinces site!
they are a lot of work ! but well worth the effort compared to buying new?
AAZ are a different breed even i know that i can not do those with the equipment i got! but some day?
as it stands now i've done 4 sets and have not heard anything being wrong!
but i am sure they would tell me if they were!
Duane

[Vincent Waldon]

True, some people can break a crowbar in a sandbox.

Having said that,  based on all the email I get:

- there's a healthy appetite out there on the Interweb for working on these beauties ourselves
- many people are hundreds or thousands of miles from a shop that even knows what an IDI diesel injector is
-  there are still things I can do to make my particular instructions clearer... and I will.  

Might even add in a story about a little shop in Burnaby...    :wink:


All in all... I'm just happy to see people going ole skool and actually getting greasy... becoming less and less common these days sadly.  And if you break something... well, you tried and you learned.  Perhaps you learned to read the instructions ??!!!

AFAIK there are exactly two 1-man shops in Edmonton, a city of nearly 1 million people, that will still happily work on air-cooled VWs.   :cry: