Leakage Around Injectors? 1HDT Issue

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CaptBeardilocks

CaptBeardilocks

Joined
May 23, 2019
Threads
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709
Location
WNY For Now
My newly refreshed 1HDT is leaking air and/or fuel around the base several of the injectors. The injectors were rebuilt and all new seals added (from the rebuild company). About 15mi on them since then. At the same time pump & turbo were upgraded to G-Turbo Green etc.

I can’t 100% say for sure if the fuel is being forced out of the prechamber around the injector or if it’s leaking down from the return line. I’m going to replace all seals again and see what I get. Either way there’s some small amount of air obviously creeping around the injectors.

Has anyone experienced this? Ideas if the cause?

Photo of out of focus air bubbles in diesel fuel at the base of the injector.


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Literally in the middle of this now. Same setup. Are they rebuild OEM inhectors or aftermarket? Did you use the OEM o-ring or the aftermarket? I noticed I tiny variance in the OEM vs non-OEM o-rings.

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Hey Joey,

They're OEM injectors rebuilt by BECS Pacific I think (without pulling up my records). I honestly can’t remember if they are OEM O-Rings or if I used what they sent back with the injectors. I know the return line copper gaskets are the ones the sent and those don’t fit great.

Honestly I figured the o-rings were more for keeping junk OUT. Id have thought the copper seat would stop and pressure/fuel…
 
CaptBeardilocks said:
Hey Joey,

They're OEM injectors rebuilt by BECS Pacific I think (without pulling up my records). I honestly can’t remember if they are OEM O-Rings or if I used what they sent back with the injectors. I know the return line copper gaskets are the ones the sent and those don’t fit great.

Honestly I figured the o-rings were more for keeping junk OUT. Id have thought the copper seat would stop and pressure/fuel…
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Funny you mention the copper seals. I used Fred Holmes in B.C. for the injector pump and couldn’t be happier. He knew I was putting in new OEM injectors so asked if I needed those funky washers. I didn’t have them yet EO said yes. Pretty sure JIS were aftermarket because they have a slightly different shape than OEM.
 
I just ordered a new round of OEM o-rings, return line washers, and copper seats. If that doesn’t work I’ll probably try to add a small space to the injector hold down forks so the injectors “pull in” a bit tighter.

Can’t think what else the issue could be. Unless my intake valves are leaking a bit of compression when closed.
 
I was just digging through my parts bin and found the OEM o-rings. So I must have used the rebuilder-supplied parts. As soon as my return line washers show up I’ll swap everything back to OEM. Be great if it’s that easy right? Lol.
 
I'd use OEM seals at the head. Placement of the injector tip is critical to getting correct swirl pattern etc for combustion.

Double check that no old seals are left in the head. They can be a bear to get out, and it's not uncommon for the odd one to be missed and left in when new injectors get installed
 
mudgudgeon said:
I'd use OEM seals at the head. Placement of the injector tip is critical to getting correct swirl pattern etc for combustion.

Double check that no old seals are left in the head. They can be a bear to get out, and it's not uncommon for the odd one to be missed and left in when new injectors get installed
Click to expand...
Yeah I had that issue on one injector
 
Follow up here: Pulled the injectors when my new OEM seats/seals got here from Dubai.

The o-rings were obviously smaller than the OEM ones and the copper seats were surprisingly fatter, by around ~0.6mm according to my caliper that had a dead battery.

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As @mudgudgeon mentioned, injector height is critical for spray pattern in the 1HDT. I wasn’t expecting to see a performance difference from the small height difference but…

After all injectors were re-seated & sealed, I was happy to have zero leaks for starters. But I was really surprised at how much better the truck runs now. Completely surprised me. Much smoother, less knock/shake at just-off-idle RPM. I wouldn’t have really said there was something “wrong” with it before but it wasn’t exactly RIGHT either. I’m still tuning the truck… But it sounds much better now.

So the PSA for tonight is: use OEM seats & seals. The aftermarket or otherwise supplied pieces don’t cut it.
 
CaptBeardilocks said:
👍 Follow up here: Pulled the injectors when my new OEM seats/seals got here from Dubai.

The o-rings were obviously smaller than the OEM ones and the copper seats were surprisingly fatter, by around ~0.6mm according to my caliper that had a dead battery.

View attachment 2714108

View attachment 2714110

View attachment 2714111As @mudgudgeon mentioned, injector height is critical for spray pattern in the 1HDT. I wasn’t expecting to see a performance difference from the small height difference but…

After all injectors were re-seated & sealed, I was happy to have zero leaks for starters. But I was really surprised at how much better the truck runs now. Completely surprised me. Much smoother, less knock/shake at just-off-idle RPM. I wouldn’t have really said there was something “wrong” with it before but it wasn’t exactly RIGHT either. I’m still tuning the truck… But it sounds much better now.

So the PSA for tonight is: use OEM seats & seals. The aftermarket or otherwise supplied pieces don’t cut it.
Click to expand...
Glad you got a good result. Good to know it made a difference too
 
with all this injector talk with pulling them out making sure the right seals and washers are put in how come no body talks about cleaning the carbon from the injector hole? maybe a reamer like this can be used??

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veiloctane said:
with all this injector talk with pulling them out making sure the right seals and washers are put in how come no body talks about cleaning the carbon from the injector hole? maybe a reamer like this can be used??

View attachment 3474196
Click to expand...
I've used similar tool to reseat the valve sealing surface in brass valves (fawcet?).
They need s steady/ gentle hand. Its easy to take too much, or leave chatter marks in the sealing surface.
Cast iron is soft too.

Absolutely should be done by hand if you do it, no power tools
 
mudgudgeon said:
I've used similar tool to reseat the valve sealing surface in brass valves (fawcet?).
They need s steady/ gentle hand. Its easy to take too much, or leave chatter marks in the sealing surface.
Cast iron is soft too.

Absolutely should be done by hand if you do it, no power tools
Click to expand...
yeah, I agree by hand maybe even just your fingertips and the weight of the tool to just only remove carbon.

i didn't do this last time I had my injectors rebuilt... but now my pump is leaking I'm going to rebuild both of them at the same time and this time I'll pick up the tool
 
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