Differences between the Germany and France injector bodies

[ORCoaster]

I am on a quest to get my Caddy running a bit smoother.  I purchased a pop tester and went through about 20 of the old injectors I have to see what condition they were in and if cleaning would yield me a set that was balanced and had good atomization. 

What a pipe dream!  Those suckers were pissing out the hole so bad I had to laugh.  But I took some time to clean up a set to see where they would come out pressure-wise.  An exercise in diesel fuel folly land.  I then went online to be sure that what I was doing was good enough and the general consensus of cleaning tips to get them to work. 

Most of the injectors people are running are doing so poorly.  One guy had like 55 injectors in his shop and he found 5 that worked as new.  What does that tell you. 

So being fat with cash from a fence build I did a bit ago I purchased 4 new Bosch tips from Rock my Auto.  They came in the mail today so I put them in the clean bodies I had and proceeded to pump them up.  HOLY SMOKE Batman,  Talk about a difference.  Atomization was so much different than I think I tested all four injectors and got about the same amount of diesel in my catch jar as I did with one of the many in the group I tested prior.

I can't wait to put these in tomorrow afternoon and test the ones in there currently.  With nearly 140 K on the clock, I don't think they have ever been serviced or replaced.  I am getting terrible mileage in town for a diesel.  27 to be accurate about it.  My other Rabbit normally gives me 34 and 48 on the highway. 

I read a column on the improvement of new injectors and a turbo swap made for one individual.  I am hoping for the same.

OK, enough of that.  What I noticed in my cleaning and rebuilding efforts was that when I used a German 155 bar body I got poor spray out of the new nozzle.  IF I changed and went to a body made in France I got really good results.  Could there be a difference between bodies like that or do you think it is just those Frenchies were cleaner and performed as they should?  I just find it odd that they did so much better. 

I think I may have found the reason I have been having so much trouble dialing in the turbopump on this Caddy.  Poor fuel delivery is not helped by adding a turbo and the proper IP.  It actually made the problem worse. 

Let you all know what the result of the new parts will do tomorrow.  Unless I am enjoying the ride so much I am still out on the road till late night. 

[ORCoaster]

I eventually got the injectors swapped out today.  I found one heat shield that was cracked and replaced it but other than that I did not have time to put the old injectors on the pop tester to see what they looked like under pressure.

All the injectors were in pretty tight but came out with a slow crank on the big breaker bar.  Pushed towards the head for both the removal and installation. 

No time for a test drive either.  Just going to drive it to work tomorrow morning and hope for the best.

I found my meter of tiny diameter hose for all those little nipples on the injectors.  Finally got rid of those hard leaky lines. 

Later

[Dakotakid]

So, all you did was disassemble and throw the early nozzles into the bodies with NO attempt to sand down the internal erosion on the intermediate disc or other structures? If they are running at any pressure remotely adequate, they should leak at the seam. I carefully sand my internals down to 3000 grit with precision ground block but I do run quite high pressure on turbo engines. Higher than stated in Bentley.

Did you reshape the injectors or simply replace the one broken one?

Is luck commonly employed in your life on everything else....or do I already know the answer?

The early injector bodies do look different and do not share their springs with the later bodies.

[ORCoaster]

Dakotakid, Thanks for the post.

Luck and skill have been with me for most of my life.  I don't mess up often but when I do it is some nasty business.  Like the time I ran my hand through the table saw doing some renovation work.  I lost focus for an instant, cost me 24 stitches, and no feeling in the fingertip and thumb on the left hand now.  But I count myself lucky in that I can still count to 10 and not just 8 and 1/2.

I should have elaborated some on the switching of the French bodies with the German ones.  I did indeed clean them up. Had them all shiny on all surfaces, the springs were clean, the shims were too.  I did notice a wee bit of a difference in springs and was thinking Hmm, still going to pop at 155 bars?  And there was wear on the discs. 

I initially started to clean the tips and nozzles and just bagged that as no amount of work seemed to make them work properly.  I always got streams of fuel as they popped and not so much atomization.  Clearly not what those new nozzles were pumping out.  I did all four.

When I was cleaning the parts of the different injectors I put on my 2.5 power reader glasses and then used my 25x power magnifying glass to look at all the parts for wear and tear.  Some of the bottoms of the nozzles were eaten away, probably from poor fuel delivery and burning at that point.  The internal tips of some would not come out until I soaked them for a while.  So It made me question how well they were working. 

So yes, I think I am lucky.  But I do have a skill set that reduces the problems too. 

[sgnimj96]

vintage mercedes idi cleaning tips
I don't pretend to understand it,  but that's what those old injector cleaning kits were for

[ORCoaster]

Crazy that they have a cleaning kit.  I bet those are found all over the place, NOT!

Ultrasonic cleaners were not common is my guess. 

[ORCoaster]

Well here is some weirdness I didn't know about:

I had enough time this afternoon to take those old injectors from the head and put them on the pop tester.  I used other bodies when I replaced the nozzles.  See prior discussion.

But I had one of those French bodies start leaking at the leak-off tips that move the extra fuel away from the injectors and back to the tank.  Diesel was dripping fairly consistently off the #4 injector.  When I raised the little hose to see if it might have a leak in it I got a spray of fuel out at the joint where the pipe goes into the body itself. 

So I figured to take one of the previous injectors, clean it all up and use it instead.  Well, I just grabbed one stuck it in the vice and cracked the lower part off, and cleaned the spring, the shim, and the disc, and was in the process of cleaning the body itself when I noticed 130 bar!  What the What? 

Turns out the PO had two 130 bar and two 155 bar injectors on the head.  Why would someone who spends 3500 bucks rebuilding an engine reuse the injectors in the first place?  And how did he manage to mix and match them like that?  It explains my timing issues and the lop, lop, lop I was never able to get rid of at idle.  Unless I bumped it to like 1200 rpm.

When I replaced them all with proper 155 bar ones with new nozzles it ran so much better but in light of this information, I now know why.  It wasn't just the new nozzles.  It was the balance between them all. 

Word to those experiencing problems with idle, check the pressure on those injectors.  I know it is one item I never really paid much attention to because I never thought to take them out.  My mistake, they should be at least cleaned and possibly replaced every 60-80,000 miles.  My truck, an 81 had 139 K on it.  Like I said I assumed the PO replaced them not 3 years ago.