i know this has come up before, but what is the consensus on this, is it more likely to leak around the injector or is a prechamber leak more likely?

i dont have a good mental picture of the exact relationship of all of the above.

thanks in advance.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Tom,

I was hoping my Indy could do a compression check for me, and didn't have the right fittings 8(. He returned the car with an injector return line leaking
8( 8( 8( . I just replaced a couple of the return lines tonight and have a small pool of diesel on the base of 2 injectors. I noticed the bubbles coming from the base of the injectors also. I think I have fixed the return line leaks, but I was too messy to get into the car and drive it and evaporate the diesel. I'll let you know in a day or so if the bubbles are still there.

My hypothesis... it appears there is a small vent hole of some type at the base of the injector where it screws into the head. Note the base of the injector is flush against the head for 355* of the injector base, but there is a small section that is purposely curved inward along the outside diameter. I'm guessing it is some kind of vent to allow air to move in/out while the injector moves.

Anyone else have a better idea?

Chuck

so you are thinking a few bubbles around the base of the injector might be normal?

i wouldnt have thought so, but it sounds plausible.

what about it guys? bubbles normal? of course you need some fuel there to get bubbles, like when you have changed the bypass hose.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

If you reused heat shields and there are bubbles then I'd say replace the heat shields. Even if the heat shields haven't been touched in a while I'd say change them on the chance they were fitted the wrong way.

If you have the right tool you can try retorquing the prechamber locknuts. Maybe there's a sealant you can apply to the locknut. Or a very fine copper thread.

gsxr provided instructions for machining 603.96 prechambers to work with -17- and later heads. I don't know how precisely a reworked prechamber can seal since there's no compression ring between the top of the prechamber and the head in 603s are there is in 617s. FWIW I didn't see bubbling around the prechamber in my 603 which had machine shop reworked prechambers in a -22- head.

Sixto

now i am really showing my age, anybody remember lawrence welk?

i talked to my favorite machinist today and he said no, bubbles werent normal. so i have an extra metal seal for under the injector. tomorrow i will have my bro change that and see if it does the trick. if that doesnt work it will go to my favorite machinst's shop and he will pull the prechamber out from the top and check it out.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Tom,

I may have mis-understood your situation. The reason I had bubbles was I had a pool of diesel sitting around the base of the injector from a leaking return hose. That dried up today and I have no bubbles or dampness now.

Was yours bubbling without fluid at the base of the injector?

Chuck