OM602 Injector Thread Tap

[903hblue]

So I notice injector #3 is leaning way to the side. Performance seems ok, but air is rushing out of that area. I cracked the hard line to that injector and the motor definitely tumbled, so I know combustion is still happening there.
Should I try to tap the threads? Seems a bit risky to me playing like that in that area. Anyone know what size the threads are? I saw M22-1 on a different injector, but not sure on mine. Thanks.

[Diesel911]

If your Pre-chamber Rings Rings have a slot on each side your Injectors should theread into the Prechamber Ring and the threads are M24-2.0

If your Pre-chamber Retaining Rings are splined inside your Injectors Thread into the top of the Pre-chamber itself and the threads are M22-1.5

In both cases the Injectors do not seal on the threads. They seal by way of a Heat Shield between the Pre-chamber and the Injector. So there could be a heat shield issue.

On Engines with an aluminum cylinder head the common compression leak around there is the head warps and the Prechamber seating area does not seal. There is a cutter to recut the seating area but you need special instructions on that.

You might try removing the Injector from the problem area, get the special tool and re-torque the Pre-chamber Retainer Ring and then use a new Heat Shield and re-install the Injector to the proper torque.

[903hblue]

Interesting, thank you. The heat shield is new, so no problems there.
I wonder how exactly the threads ended up like that, maybe someone already tapped? Bizarre.

[Diesel911]

Caution if you end up pulling out the pre-chamber be sure to remove the Glow Plug first or you will damage the pre-chamber and Glow Plug.

[903hblue]

Thank you!

[Diseasel300]

I'd be looking for what's stripped. Either the prechamber lock ring is stripped in the head, or the injector is stripped in the lock ring. Neither is great news.

[903hblue]

Mmm, I’ve already removed the injector, which is not stripped. I’m not sure I see the connection between something stripped, and the injector threads being wonky.

[Diseasel300]

You have 2 threaded parts here - the head and the prechamber lock ring. They will not go together crooked unless someone stripped the lock ring into the head, or stripped the injector into the lock ring. If the threads are good on the injector, your issue is probably the lock ring being stripped crooked into the head. The injector screws into the lock ring, not the prechamber.

[903hblue]

Ohhh I understand. Well ****.

[903hblue]

What would need to be done for correction?

[ROLLGUY]

How about some photos?

[903hblue]

I’ll get some photos up tomorrow

[903hblue]

Couldn't get any good photos without removing the intake crossover pipe, so that will have to wait until at least tomorrow.

Seems like the injector is not making a good seal against the heat shield.
Does anyone think tapping the threads would help to straighten up the injector? I wonder if there is enough meat there to tap properly. Makes me nervous to attempt, like a one try do or die type thing.

[Diseasel300]

I wouldn't try tapping it, personally. If the threads in the lock ring are screwed, just replace the lock ring. Remember that you have full combustion pressure acting against the injector. I don't think it would be a fun day to have that come blowing out of the hole while driving down the road!

[903hblue]

Wait, won’t the threads on the head be screwed, since you think the lock ring was cross threaded?