My Bosch rebuilt injectors have a so, so spray pattern...
 

I took my two year old "rebuilt" injectors to the Bosch shop to get tested. I noticed a very slight drop in mileage last year, and well now I know why. The pop pressure is fine across all 6, and they won't leak down, but the spray pattern is so so at best. They spray heavy and don't atomize the fuel nearly as well as they should. They hooked up another MB injector that they had just rebuilt to show me the difference, and yep it was a lot better. The guy who tested them said they are not really bad enough to rebuild, but not that great either. He said I should run them for another year and run a lot of cleaners through, to see if that doesn't improve them. If they don't clear up by the fall I'm going to have this local shop do them.

I still regret replacing the originals, they were probably better than these.

Injector nozzles
 

member:

C Sean Watts

sells the Monark injector Nozzles (made in Germany) for about $20.00 USD each.

If it is effecting your fuel milage it sounds cheaper in the long run and for that reason alone to replace the nozzles now. It should also allow for easier starting and less carbon build up; especially until the engine is up to operating temp.

What were the "rebuilt" injectors that you put in two years ago?

Source?

I've questioned the "rebuilt" term on these for awhile. It could mean just a dunk in some cleaner..........no nozzle replacement.

Probably another scam.

One person's tuneup can be another person's rebuild. Rule of thumb: always get as much detail as possible.

They were ordered from Worldpac, so God knows where they got them from and who "rebuilt" them. I had a heck of a time when I first got them, the car ran like crap and I had to send a few back before getting a good set.

Yep.........no surprise there. Anybody "rebuilt" them and you paid way too much for it.

Leason learned, just cost me a few hundred to learn it.:rolleyes:

Balacing & 'pop testing
 

So, What are you guys paying for balancing & pop testing? I just cleaned out a set of injectors, changed a set of nozzles (Thanx Sean! ) and had them balanced and pop tested. And I paid enough for balancing & pop testing, to be reluctant to say:rolleyes:

What are the choices: Buy new if you can find them, exchange for rebuilts, have a local shop rebuild them, take a chance on a used set, or rebuild them yourself.
For your 2 models of Mercedes it is possible to by rebuilt injectors off the internet for around $40 each (in the US) if you take the time to search for them. Added to that is the cost to ship them to you and the cost to ship back the old ones (cores) to get the money back for your core charge.
What did you get for that money: A set of injectors that are not as well balanced as the local shop would do and spray nozzles made in an unknown country.
Since the unknown country Bosch spray nozzles alone are selling for around $30 or more each the spray nozzles frim Sean C Watts are a good deal especially since you know what you are getting.
So compare the overall cost (don't forget the shipping) and QUALITY of buying rebuilts off the shelf and paying to have injectors done by the private shop with quality parts and I think you are ahead in the long run.
So lets say you supplied your own spray nozzles and you payed $30-40 each injector for labor (which I think is a little high). The local shop is going to do a better job on them as they know you are local and can come back for warrenty work.
You have to consider it an investment.

I was thinking of having this done. The diesel performance guy in that article is right down the street from me. I imgine this was for DI engines and not IDI, but who knows. If the price really is $40 and the increase in performance that tangeable, why not?

Balance and "Pop" test
 

Testmaster

BOSCH Service Center

Whoeeee! $36.00 each

(I can borrow,make or buy a tester...And I sure know how to balance and test.)

balancing
 

Your logic is pretty sound. It's an hour drive to go yell at the guy if he did a crappy job but I still have that option so I agree with you about hiring local labour.
I am VERY happy with my transaction with Sean for 265 nozzles. of course I haven't run them yet but I expect no problems with the nozzles they were packed very well and I think are probably a good product.(And a good Price)
I paid nearly $50 each for balancing and pop testing:rolleyes: at a Bosch approved shop in Calgary.
I think I will either buy a pop tester off E-bay or make one before I do the other car. If I find I like doing it maybe I'll lay a supply of shims and start doing them for others:D

Alberta Luthier, what shop did you use for injector testing?

I just had my injectors tested at GCL Fuel Systems in Calgary, which is a Bosch authorized shop. They quoted $55 to test four of them (and the quote didn't mention the additional $11 in shop supplies and surcharges that showed up on the final bill). However, they did tell me that they all tested OK and had a good spray pattern and pressure, so I appreciate their honesty. The place was really clean and the staff was friendly.

If rebuilding or cleaning was done, they said it would be about 1/2 hour ($55) per injector to disassemble, lap, seal, and balance if necessary. Fortunately I didn't need to do have this done.

Injector heat shields ($0.96 online) were $6.99 each there. I try hard to support local businesses but I can't when the price difference is that big.

He's increasing the fuel flow into the piston with his internal polishing of the injectors. You'll get more apparent power, but that's because you'll be putting more fuel in all the time. In other words, won't you just be hitting max load at a different throttle position?

Of course, you'll also get more than stock max load at WOT, so if you then play with the boost, you can get beyond stock HP before needing to diddle around with the max load setting on the IP. Has potential.

Yes and no. The result of the Extrude Hone process is an injector that flows more fuel than stock or a so called "high flow" injector. At a given "throttle" setting the IP is still delivering the same amount of fuel as it was before so the modified injector does not increase fueling by itself. What is does do is inject that same amount of fuel in a shorter period of time, expressed in degrees of crankshaft rotation. Injecting the same amount of fuel in a shorter period of time means that there is more time, again in degrees of crankshaft rotation, for combustion. This CAN increase power simply from a more complete combustion process. Obviously the modified injectors also allow more fuel and help to maintain the injection time period when the IP is turned up. Clear as mud. RT

I don't think it's quite that simple. Backpressure from restriction in the injector shouldn't affect flow rate too much in this situation, because the IP plunger will just push it through at a higher pressure, maintaining the same flow rate... that is unless you attribute a delay in injection to flexing of the high pressure injector lines...

In short, injection duration should remain pretty much the same.. unless the system actually does flex enough to make this effect occur, in which case this mod, combined with adjusting the pop pressure to a higher setting, should result in significant (measurable) gains in power, and conversely, fuel economy, especially in the high end of the rev range where timely injection duration is of the greatest importance.

EDIT: It is important to remember that the IP really doesn't "care" what pressure it is seeing. It can handle many times the 135 or so bar at which the injectors pop.

From what I read on Extrude Hone process i got the impression they were talking about direct injection injector spray nozzles that have multiple tiny holes in them. On direct injection nozzles the seat of the injector pintel has a lot of metal around it and is exposed to combustion by way of the tiny holes.
Pintlel type nozzles normally (as in Mercedes) have only 1 hole in them and part of the pintel stick out into the combustion chamber. If you enlarge that hole enough (extreme example: if you enlarge the hole enough the pintel will fall out of the injector) you are going to get more carbon particles under the seat and expose more of the pintel seat to the heat of combustion. For racing this is not a problem but for everyday use you want longevity.

I did get mine done at GCL as well. The injectors are VW 2 spring AAZ injectors with new Monarch 265 nozzles. Although I had thoroughly cleaned the injectors and installed the new nozzles, I wanted to be sure they were balanced, (150 bar) and pop tested. So I knew I would have to pay for some time but having spent quite a bit of time cleaning them out ( Boy do they ever get cruddy in there!) I thought I might get billed for actual shop time not 1/2 hour per....
What really counts for me anyway is: Did they do it right? I hope so. I expect so. And I can hardly wait to scrape a couple of hours of free time together so I can get 'em in and find out.:D
I keep changing my mind which car to put 'em in they both need them!