Injector to head sealing

[bugnut]

I just fired up the franken engine I have been working on for the last 2 years.  Everything is great except the leak between the injectors and the head.  The head has been rebuild and the injectors were rebuilt from giles.  I installed new heat shields the first go around and it leaked.  I can see bubbles between the threads and the injectors.  I bought new heat shields and put them in on just #1 cylinder and torqued to I think it was 52ft/lbs.  Restarted and still have leak.  I spray soap around the injector at the head and get bubbles.  What do I do from here?

[BAM]

Are you leaking compression or fuel?

[bugnut]

It looks like compression. 

The bubbles the first time were from the anti-seize I put on the threads. 

[BAM]

If it is compression and all has been torqued to spec and there is no marring at any of the mating surfaces, no worries.  The minor leaks will seal up with heat cycles and carbon in a few hundred kilometers.   

[bugnut]

Now it seems to be leaking fuel out the threads.  I clean the injectors and head with brake clean till they are bone dry. After 10 miles of driving check and find fuel at the threads.  I have some old injectors laying around would it be worth it to try those or should I send these injectors out and get them tested?

[jseeley]

If you leaked any diesel into the threads it will bubble as it boils off and sometimes takes a couple heat cycles to stop.  The soap will also bubble as it boils off.  Bad test.

If it is compression and all has been torqued to spec and there is no marring at any of the mating surfaces, no worries.  The minor leaks will seal up with heat cycles and carbon in a few hundred kilometers.   

I can attest to the above. If it's not leaking a huge amount, I would give it a little time if you can. I too was disappointed after putting everything back together with a new pump, seals, and injectors to find I was leaking from one injector. However after a few weeks (heat cycles) it actually stopped completely and and hasn't leaked since.

[BAM]

Sometimes you will get leaks from the return lines after things heat up.  Check it when it is hot, watch you do not feed the engine the brake clean it run away and make some nasty noises