D7 3T Fuel Injector

[texaspatd73t]

Having a problem with a leak around fuel injector on a D7 3T. Could hear leak and looked up in parts book to see if there was a seal between injector and pre combustion chamber. Ordered seal and I have tried twice to install. Did not see any evidence of old seal. Both times seal has flattened out and tore.
Anyone have any ideas, is there really supposed to be a thick seal between the injector and chamber. Seals look like thick cork. Could I use maybe a copper washer as a seal?? I am sure to be losing power because of this.

[Old Magnet]

The original arrangement had a "cover" retainer as well as the gasket.

Attachment 21640Attachment 21639

[texaspatd73t]

Does have the caps in place but gasket still spread and tore. Might have something to do with not having proper wrench to install. Had to get tight with hammer and chisel. Guess I will try again looking for any roughness that might tear it.

[willitrun]

i thought cork was to keep dirt and water out, seal between combustion chamber and injector was taper between the two.

[willitrun]

i've used red silcon, works good

[Julian]

This is interesting, I've got an injector on my D4 that always looks a bit wet with diesel around the area of that cork seal - I guess fuel is migrating up from the bottom due to a tiny leak and pressure of combustion gasses.

What are those serrations for on the injector body - are they just to keep the injector from turning?

Cheers

Julian.

[Old Magnet]

The serrations/splines were utilized by matching sockets to assemble and disassemble the units.....not for gripping with pipe wrenches as the chisel set would do.....

[STEPHEN]

Daryl & OM is correct

[edb]

Hi texaspatd73t,
the injector leak you mention as being power robbing is sealed to the pre-cup by tapered lapped surfaces.
The cork seal is only to keep dirt/water etc out of the space between the injector body and the precup.
All the ones I worked on at The Dealer that leaked combustion at this point had dirt on the seat. The seat and injector then needed to be lapped with grinding paste to get a good seating.
Another thing to look for is that the injector retaining nut and pre-cup threads are clean/rust free so that the nut can be screwed in without binding and can actually exert clamping pressure on the injector so it can seat tightly into the pre-cup and seal effectively.
There could also be a combustion and fuel leak if the injector body has been loosened in its retaining cap nut. This will require the injector to be dismantled cleaned and its own sealing faces lapped with special fine paste.
The injector then needs to be thoroughly cleaned and all its adjustments and tests attended to.
Hope this helps.
Cheers,
Eddie B.

[texaspatd73t]

Makes sense, thanks as always for the great information.