Bosch injector differences

jbg · #1 02-03-2010, 04:03 AM

I've been collecting some injectors from diesels at the local pick-n-pull so I can rebuild them and swap into the car for minimal downtime. Due to the scarcity of VW indirect-injected diesels I have been sourcing parts from Mercedes Benz vehicles.

My plan was to replace the nozzles with the appropriate part, pop test, and shim as necessary. I have noted that several of the injectors I have gotten are shorter then a D24T-specific injector I have as a reference. These came out of turbo and non-turbo 4 and 5-cylinder engines -- what was available at the time.

Note the difference in height. The injector on the left is from a turbo Mercedes, it is the same dimensions as that of VW/D24(T). On the right is the non-turbo injector. The non-turbo injectors have a breaking pressure of 135 bar as noted on the body.

Note the measurement with my cheap Harbor Freight caliper, this is the turbo MB (same dimensions as VW/D24(T)).

Measurement of the non-turbo injector.

Even the hardware inside them is different. The smaller non-turbo injectors have longer springs and shorter spring seats (three on the right):

Any comments from the collective? I assume I can use the shorter units. As long as they pop to my specification, and they have the VW nozzles, I assume things will be fine.

Jason · #2 02-03-2010, 05:19 AM

The shorter ones are earlier injectors, they would be early 1.6 or 1.5. I also got a bunch of the shorter ones, but I just used them for the shims and built all tall style. I suppose you could use the early style short ones, but I wouldn't mix and match on your engine.

Jason

Jason · #3 02-03-2010, 05:22 AM

Come to think of it non of those injector bodies look right... There should be a smooth sleave looking area below the threads. Those threads are pretty fine looking as well. I don't think you have the right ones there...

Jason

Jason · #4 02-03-2010, 05:25 AM

What you have pictured there wont work in your D24t. I don't know what you have for a reference injector but thats not the correct one either. You may be able to use the shims out of it for shim selection when you go to pop test them and set the pressure. Having extra shims will come in handy. Here is what it should look like:

http://www.dieselvw.com/16NAInjector.htm

Jason

jbg · #5 02-03-2010, 06:46 AM

Quote:

Originally Posted by Jason

Come to think of it non of those injector bodies look right... There should be a smooth sleave looking area below the threads. Those threads are pretty fine looking as well. I don't think you have the right ones there...

Jason

Jason,

Are you referring to the lower half of the injector that threads into the cylinder head (course threads), and the other end into the upper portion of the injector? If this is the sleeve you mention, it is the same height and dimensions for both injector types. My pictures only show the upper half of the injector, cause that is where the difference is.

Jason · #6 02-03-2010, 04:22 PM

Ya I don't know what I was thinking.. Somehow I thought that was the whole damn thing! Same as the injectors I got too, the non turbo shorter ones came on the earlier vw 1.5 diesels. As you said, if you get them up to the correct spec on pop pressure, they will be fine to use, but I would still only use all the same style in your engine.

Jason

v8volvo · #7 02-03-2010, 11:14 PM

Don't forget that it's not just a matter of getting the injector to pop at the right pressure.... you also have to be able to install it into your engine, and that's not gonna happen if the injectors are not the right shape, or especially if you try to mix and match. The metal fuel injection pipes are a certain shape and are not very flexible -- they will only work if you use the correct type of injector with them. If you try to use the wrong kind, and you install the lines in a stressed position, they will fracture, guaranteed.

The lines are fragile enough as it is -- I have replaced fractured pipes on two different D24s just in the past week or two. As they age they get more and more brittle and susceptible to failure. Don't try to install them in any position they are not "comfortable" in or you will need to get ready for a fuel bath...

jbg · #8 02-04-2010, 03:54 AM

Quote:

Originally Posted by v8volvo

The lines are fragile enough as it is -- I have replaced fractured pipes on two different D24s just in the past week or two.

Thank you both for the replies. v8volvo, where have you sourced the fuel supply pipes?

Jason · #9 02-04-2010, 04:45 AM

There are a couple sets for sale in the for sale section right now.

Jason

lmwatbullrun · #10 07-28-2010, 03:23 PM

how difficult is it to fabricate the lines? ANyone done that?