DIY 617.9XX prechamber tools - Page 4 - PeachParts Mercedes-Benz Forum

Diesel911 · #46 08-13-2012, 12:11 AM

Quote:

Originally Posted by macdoe

I am not sure how you would tell. I bought a set of 2.0 mm which is stock (no re-surface to the head). We ended up having the head re built and in doing so the machinist resurfaced it and removed .012. He stamped it on the surfaced part of the head and so it would be impossible to tell it has been resurfaced without taking the head off and then you would have to see the stamp. I guess this is why people tell you to double check your prechamber protrusion into the combustion chamber after the prechambers have been torqued in place with your new crush washers.(also done with the head off).

We had to order the first oversize prechamber crush ring which is 2.3mm.

Since I had both 2.0mm and 2.3mm I decided to measure them to make sure I got the correct oversized ones sent to me. I also thought when looking at these two different sizes side by side that they looked like the same size. Being that you probably can't actually see .3mm with the human eye...this makes sense. The two rings were different sizes when measured with calipers...just how much...I can't remember. I think it worked out to close to the .3mm I was after.

What they measure out at once they have been torqued down once is another story...I don't know what they would be.

I have been thinking this same thing through..... If the car changes owners.... how will the next owner know that the prechambers, if removed... will require the oversized seal rings? I guess I'll have to remember to tell them.

See if you can remember this. I noticed that the Standard sized Prechamber Ring had one groove around the outside diameter.
I am guessing the next larger size has 2 grooves and so on.

Diesel911 · #47 08-13-2012, 12:27 AM

Quote:

Originally Posted by macdoe

We could measure our old crush rings and compare but I guess there are many variables and very close tolerances to consider. I think I have the old ones around still.

I suppose if the Head was already on the Engine and you had not done the protruding measure you make sure the Piston is not at TDC and install the Prechamber without a Sealing Ring; ues the Retainint Ring to make sure the Prechamber is all the way down bottom but remove the Retaining Ring when that is done.
Get a Dial Indicator and install it so the Pointer is on the lip of the Prechamber with some preload but set at Zero.
Crank the Engine slowly and let the Piston push the perchamber up and read the Dial Indicator at the highest point of travel.

You would use that indicator measurement and figure that amount to the amount of clearance you want and use the total of the 2 to determine the thickness of the Seal Ring.

Due to not being able to calculate the crush on the Sealing Ring it would be best to target how much you need to add to the get them Max clearance.

The above is an imperfect way to do it but safer than guessing.

Diesel911 · #48 08-13-2012, 01:18 AM

About a Month ago I bought a bunch of used Mercedes Tools or I should say abused Mercedes Tools as they almost all showed heavy handed use.

Below is a Prechamber Puller made to use with out a Slide Hammer. It looks like a Homemade job but it has KD and a Logo stamped on it and I have other Tools made by the Same Company; so it is not homemade.

However, you can see the weakness of the thin tube Tool design and it is a Tool that I think could only be used on an Engine with an Iron Cylinder Head.

Like the other Tools it was not used with care, there is a crack in the one picture caused the locating tab of a Precombustion Chamber. Evidently the User of the Tool just kept turning it further than the Tool was made to pull the Chamber.
The tube is also slightly warped; and it look as if someone hammered it back into the shape it is in now.

It will be a good Tool to take to the Junk Yard because it does not need a slide Hammer. But, I think at Home I wolud continue to use the Slide Hammer.

Mercedes used to make an extremely sturdy no Slide Hammer Prechamber puller. But, you need to remove the Valve Cover as it sits on 3 points; 2 are on top of the Head Bolts and the other point is on the flat surface where the Vlave cover would go. The picture is in the FSM.

About 1-2 times a year that Tool comes up on eBay but is expensive.

The KD Tubular Prechamber Tool seems to be made to avoid removing the Valve Cover and I guess to be a cheaper Tool.
But, I think the space would be a little cramped when you use it.

whunter · #49 09-24-2013, 07:04 PM

for a new owner.

.

ichris93 · #50 08-14-2014, 06:28 PM

Quote:

Originally Posted by Billybob

Actually some you can't and some you can!

You can make use of a nozzle holder/injector body if it is the inclined injection type found on OM602.962 and OM603.971 turbo engines 201-87 190D Turbo, 124-90 to 93 300D turbo, 126/140-91 to 95 300SD/SDL turbo cars. These engines use the 5 degree inclined injection system which has its nozzle holders/injector bodies that have M22X1 thread which threads directly into the prechamber itself. These are most easily distinguished by the finer threads nearer to the end of the nozzle holder/injector body and the smaller injection line connection which uses the 14 mm nut.

I stand corrected on this! You would only be able to use an inclined nozzle holder to fabricate a puller for inclined prechambers. D911 is correct on the threading of none inclined injectors and there corresponding prechambers! Thanks!

So what is the thread of the prechamber of an inclined injection prechamber found in the OM602 turbo engines?

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