Idi injector style - threaded and sleeveless

[rreegg]

So just starting to get my hands wet with injector work - not on the idi yet but another small diesel engine.

Pulled the injectors on a Volvo penta and they are press fit with copper sleeves. This actually seems to be somewhat standard from what I can see?
My only other frame of reference are idi injectors which seem to thread directly into the head with no sleeve.

Anyone know why this difference is? Maybe a benefit of the sleeve is you could replace it in case of fouling but are easier to get stuck. Where threaded might be easier to pull but more likely to damage/cross thread etc.

 

[Nero]

The sleeve is for a coolant passage, the injector tips are coolant cooled on bigger engines. The sleeves are known for leaking at times too, causing coolant in the fuel.

 

[Rdnck84_03]

The sleeve is for a coolant passage, the injector tips are coolant cooled on bigger engines. The sleeves are known for leaking at times too, causing coolant in the fuel.

Not super common but an issue that the 7.3 powerstroke has. It is normally fuel in the coolant though. Coolant pressure is usually around 15 psi, fuel pressure is around 60 psi.

Guess after shutdown the coolant would have more pressure until it cools, but haven't really heard of them transferring coolant into the fuel.

James

 

[Nero]

Not sure how the power strokes work, but in the big rigs, the coolant that leaks into the fuel is on the return side, so usually zero pressure.

 

[Rdnck84_03]

Gotcha. That makes more sense.

On the powerstroke it is a fuel gallery in the head under full regulated pressure. The pressure is regulated at the filter housing.

James

 

[rreegg]

The sleeve is for a coolant passage, the injector tips are coolant cooled on bigger engines. The sleeves are known for leaking at times too, causing coolant in the fuel.

gotcha thanks, i pulled an injector and it came out with the sleeve and had read there might be a coolant passage there but just sort of left things. gonna leave it be until i can source a new sleeve.
but othewise was curious because don't believe the IDIs are sleeved