om606 Head thickness at injector well...

[Proctor750]

This motor I pulled was sitting for a long time and all the wells were filled with water. I have no idea...


It appears the only damage to the head (so far) is in the 4th injector well where the prechamber seats against the head.


It's hard to tell if it goes through or is just a cavity, I need to get a mirror and play around more.



Any idea what the thickness is here and if there is a water journal looming nearby..? I am not familiar with the internal layout of this head.

[Diesel911]

There is good news. The part that the 2 arrows point. My eyes are not good enough to tell if the heatshield is still there or not but. If the heatshield is still there removed it and replace as you are supposed to do each time the injector is removed and replaced. Make sure the heat shield goes in correctly.

Above that are the threads where the injector screws in. Those 2 areas being good are all you need for it to function correctly.

If in the picture that area where the read arrows is pointing is rough around the outer edges the cheapest way to go is to clean it up the best you can and see if a new heat Sheild will seal it.

If it does not sea, I have not read of any reseating tool that goes inside of the prechamber to renew the surface. You would have to invent something to do that like somehow attaching a heat shield to something and using some lapping compound to smooth it out.

What the rust issue is most likely to cause is difficulty removing the prechamber retaining ring. As long as the treads in the prechamber for the injector are good and under that the sealing area is good nothing prevents it from functioning as it should.

In the diagram the squggled set of lines shows where your injector threads into the prechamber and the arrow points to the heat shield.

[Proctor750]

Got it, so the area in question in red below (see my edit) is irrelevant and isn't near any water or oil passages of any kind?


The diagram looks different from an om606 head based on the angle and layout or maybe it's just an odd image.



I am tempted to replace pre-chambers but the motor only has 160k on it.

[Diesel911]

Originally Posted by Proctor750

Got it, so the area in question in red below (see my edit) is irrelevant and isn't near any water or oil passages of any kind?


The diagram looks different from an om606 head based on the angle and layout or maybe it's just an odd image.



I am tempted to replace pre-chambers but the motor only has 160k on it.

I would say not but in the factory service manual on your specific engine there is a similar diagram, and it would be showing how the angle injection is set up compared to the injector and would have a similar cut away view.

The prechamber is under that rusted splined ring. Below the area you showed.

3 things can happen to the prechambers themselves. One is if you leave the glow plug in and remove the prechamber you ruin the pre-chamber. I forgot that and ruined one of mine.

Two is the ball pin inside can become loose. Not sure how that happens but it is more than just extremely rare.

The most common thing is that over time the tiny holes at the bottom of the tip of the prechamber over time erode and enlarge. That normal enlargement seems to cause no issues I know of.

Now the above is burning diesel fuel.

There is no need to remove the pre-chambers unless you are just curious. Also, the pre-chambers are in a dry hole. They are not directly exposed to coolant.

Something else. You need to have the piston up close to top dead center and the glow plug removed. When you pull out the pre-chamber it peels off deposits from the outside of the pre-chamber and they fall on top of the piston head.

When I did that after the prechamber was out I put a vacuum cleaner on the glow plug hole, and it sucked out all of those deposits. If you have vacuum cleaner attachments for clearing a computer, you might be able to get down in there and vacuum the top of the piston head through the pre-chamber hole.

Now this is not about the pre-chamber themselves. On the engines with aluminum heads, it is not unknown for the bore the pre-chamber seats in get warped. There is a cutter for that to reseat the sealing area but that is down under the lip of the pre-chamber.