Precombustion chamber collars do not want to leave the head.

[dalek]

I took the head out of my 75 300D turbodiesel to a shop to have it checked. Owner said he could take the collars out no problem. Well, he called me and said he tried everything without luck. So, I decided to pick the head and give it a try. Well, I was not very happy with what I saw (including the surface rust on it):


As you can see, those collars suffered quite a bit of abuse and still will not come out. Would any of you have an idea for how to remove them? Using the drifts shown in the picture did not got very far. I am past the point of getting pissed at it; I just want to get this done so I can put my car back together.

[t walgamuth]

I wouldn't worry about the rust.

I would ask him if he used heat.

My favorite machinist uses heat and candle wax to get the most stubborn things out.

Tom W

[dalek]

Could you elaborate on the process? Do you mean heating up the collars (torch? Oven?) and then pouring the candle wax so it pours between the threads?

[pawoSD]

I had the opposite problem yesterday! I was loosening an injector and the collar came loose with it!

I tightened them both back in, then rapidly cooled the injector, and out it came (by itself).

[vstech]

a drift will just damage things.
you need to buy or build a proper tool based on a socket with ears to grip the notches.

[vstech]

and you will have to buy new PC rings because those are now mashed pretty bad...

[TheDon]

75 300 Turbodiesel? you sure about that

[d.delano]

Originally Posted by vstech

a drift will just damage things.
you need to buy or build a proper tool based on a socket with ears to grip the notches.

yup
the proper tool would have had them out already

[t walgamuth]

Originally Posted by dalek

Could you elaborate on the process? Do you mean heating up the collars (torch? Oven?) and then pouring the candle wax so it pours between the threads?

YOu just heat it up really well, then take a candle and "color' around the joint between the parts you wish to separate. It works every time., I think he says.

Tom W

[lietuviai]

Who did that with the drift?
I don't even with the right tool they'll come out now.

[dalek]

Originally Posted by vstech

a drift will just damage things.
you need to buy or build a proper tool based on a socket with ears to grip the notches.

Yes, I actually told the shop when I drop the head to hold off while I bought the tool. It looks like a pipe of the right diameter which is then tightened down by a bolt inside it against the collar so the two teeth can grab the collar. Then you turn it by using a wrench (or a socket) over the hex face on the pipe. Unfortunately, by the time I walked in with it he seemed to have had too much idle time on his hand and decided to see if he could pop them out. I bet such techniques work wonders in, say, a SBC but someone (me!) forgot to tell him this is a Mercedes and not a Chevy 350.

It also makes me concerned: I had him rebuild the engine off my 87 Integra. At least on that one I took everything apart before giving to him. In hindsight that was what I should have done.

Originally Posted by TheDon

75 300 Turbodiesel? you sure about that

It better be. I had to do some massaging and modifications to drop that engine and tranny (off a 83 300SD) in the car. Still need to find the wiring diagram for the speedo sending unit; driving with speedo saying I am doing 0mph is a bit of a drag.

Originally Posted by t walgamuth

YOu just heat it up really well, then take a candle and "color' around the joint between the parts you wish to separate. It works every time., I think he says.

Neat! I wonder if a propane torch would suffice. I do not care much about the collars as I bought a new set (at $4 each they are too cheap not to replace them anyway).

Originally Posted by lietuviai

Who did that with the drift?
I don't even with the right tool they'll come out now.

I showed the pictures to a guy at a Mercedes independent shop and he said
the same...

And, the guy did not even use a drift, he used a chisel. And, I was told, lots of hours. IMHO a drift probably would have been less traumatizing, but now it is too late and I have to deal with the present he left me.

[t walgamuth]

I doubt that a propane torch will do it. I think he gets them red hot.

Tom W

[vstech]

I would insist on him ordering a full set of PC collars, and a replacement head from metric motors! and since the PC's are inaccessable a new set of those will be needed. agree to pay the fee you would have paid for the repairs he would have done, and take that off what metric motors will charge for the head.

[alamostation]

dalek, where did you find the collars for $4? The MB dealer here charges $21 apiece.

[dalek]

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