Does anyone have a used prechamber nut wrench and prechamber puller they would sell, rent, lease, or loan for a week or two? The puller can be rented from IMPCO, but I don't think they rent the slotted nut wrench. I just can't get excited about buying a $50 tool that I'll probably never use again.

Alternately, does anyone have any brilliant ideas on how to remove the prechambers WITHOUT those special tools?

I was hoping to just leave the prechambers in the cylinder head, but since I'm this far into the engine I'm gonna go ahead and do a full valve & head job, which can't really be done with the prechambers in place.

On a related note, I'll probably have a 12-point cylinder head socket for sale in a few weeks

This might be more appropriate for the Classifieds section, but I don't know how many of you frequent that forum; I know I rarely look there.

Thanks.

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI

Far be it from me to tell you how to go about your rebuild. That said the question begs to be asked...How much are you going to save by doing the rebuild yourself? This is the question I always ask myself when a specialty tool is involved. I personally believe "once you buy a tool , it is yours to keep forever" NO MATTER WHAT MY WIFE SAYS. ( I feel that way about old double barrel shotguns and fine rifles too! ) For instance when I did my first timing belt on a VW diesel I looked at the cost of the dial indicator and adapter for setting the injection pump. ($169.00 at the time) I then subtracted that from what VW charges for a timing belt change. (average of $350.00 around here) I then decided that even if I NEVER did another one again, it was a good deal! Of course I do about 4-6 per year, so the tool has really paid for itself If you end up buying the tools you need, I may be interested in them when you are done, I have to do a head on my '84 300TD. Just a thought, and maybe it will "help" you in making a tough decision easier! Tom

I don't know about the prechamber tools in particular, but I can guarantee that the overall rebuild will be MUCH LESS EXPENSIVE if done yourself than driving it into a shop.

ncarter, email me privately if you want to borrow my wrench, I don't have the puller though.

Have a great day,

Larry I can'''''t say enough about your offer to ncarter. I wish all the people up here were that helpful.
I have the wrench gizmo you use to take the nut off with and I also have a threaded tool you screw into the prechamber to pull it out with. I bought both of them from preformance out of cal. If either one of these tools can help either one your welcome to use them. Larry Thank you for taking the lead I needed a little reminder to try and help others

__________________
Ricali

03 C240 4matic wagon
95 300E 234,000
7 prior 240;s 5 still going
81 300sd gone
65 230sl gone
49 Studebaker Champion
90BMW convert.167,000
60 Dodge D-100

Just in case anyone wants to make a puller, it can be done. The prechambers in my 74 240D were really stuck (maybe they always are), and I didn't feel like getting the expensive tools, so I made my own.
This is what I did: I had an old, broken prechamber lying around, so I used it as a die to make threads on a piece of 1/2" brass plumbing pipe. It turns out that that 1/2" plumbing pipe is exactly the right size for these threads, and it is hollow, so you can put a bolt through it. To make the threads, I used my little Sherline milling machine to make vertical slots through the internal threads on the prechamber. This can easily be done with a Dremel tool, but you have to make the cutting edges sharp, and cut out as much of the threads as you can. Ideally, you would have about 6 or 8 cutting edges about 1/8"-3/16" wide with all the threads in between removed. Then file the end of the pipe so that you can get it started to thread and use a pipe wrench to turn it. I used another old head to hold the prechamber, but you can find a piece of pipe or an old socket that fits around it and cut a slot for the little protruding tab. 3/8"-1/2" of thread seems to be enough. I found that a 3/8" carriage bolt head would just fit inside the prechamber threads, so that is what you use to pull with. The angle of the prechamber hole and the lack of a regular surface makes pulling somewhat difficult after the prechamber is raised up a ways, but until then, you can use a socket on top of the grooved nut to pull against. Afterwards I used soft plastic and wooden wedges with a steel plate on top.
An alternative to cutting the threads yourself is simply to have a machine shop do it, as they can set their lathes to cut practically any combination of pitch and size. Test the thread pitch against several smaller metric bolts to see what it is.
I hope this can be helpful to someone.

Hmm.

I don't have my engine manual handy (machine shop has it). From my knowledge of all the stuff I've taken apart so far, combined with the photos in Performance Products' catalog, it looks like everything works like this:

- The prechamber is pressed into the head.
- The lock nut is screwed into the head on top of the prechamber to prevent the prechamber from coming out.
- The nut wrench screws into the threads in the prechamber where the injector goes, and the toothed sleeve locks into the slotted lock down nut, rotates around the inner bolt of the nut wrench, and tightens or loosens the lock nut.
- For removing the prechamber, the body of the puller screws into the same threads as the injector and the nut wrench, then you use the weight on the rod to "tap" out the prechamber from the head - the same as the impact puller for the bearing pins of the timing chain slide rails.

Did I get all that right? If so, then it one could fabricate a puller using the threads on an injector or the nut wrench as a template for the threads of the puller.

---
Tom,

Yep, I realize I'm saving money by doing the work myself. I've got to use a machine shop for some of it, of course. And, I hope to NOT have to pull the prechambers out of this particular car again for a long, long, long time!

I guess I should hang on to the 12-point head bolt socket, though... since I should probably re-torque after a thousand miles or so, right?

- Nathan
'83 240D "Steiner"
'00 new Beetle TDI

nathan
you got it right from what I remember and that was way back for me (about 5 months) just as a point of info I soaked the pre chambers overnight with a good penetrating oil . I still couldn't get one out because of stripped threads. I finally used a large tap , screwed it in and kept turning with a socket on the end of the tap. more oil of course but it popped out after a bit. when I installed the new one I put never seize on them. but at 330k I don't think they will be out again

good luck

__________________
Ricali

03 C240 4matic wagon
95 300E 234,000
7 prior 240;s 5 still going
81 300sd gone
65 230sl gone
49 Studebaker Champion
90BMW convert.167,000
60 Dodge D-100

nathan

sorry forgot to mention watch out for the little alignment knotch the prechamber needs to come up above it before you start turning.

__________________
Ricali

03 C240 4matic wagon
95 300E 234,000
7 prior 240;s 5 still going
81 300sd gone
65 230sl gone
49 Studebaker Champion
90BMW convert.167,000
60 Dodge D-100

From what I've read on the M/B diesels they use stretch bolts. Like VW and probably every other engine of German origin. So, in this case YES I'm most certain that you will need to use THAT tool again...at least once. On Vw diesels you torque the first time, run the engine till warm and then give all the bolts 1/2 turn with a breaker bar then run the car 1000km and give all the bolts ANOTHER 1/4 turn each in sequence. It is the last one that always gives me the willies. It's hard for me to drive a car 650 miles and then ( even though it's running fine) give all the head bolts another quarter turn. My heart is always in my throat, and I'm thinking...gee I sure hope quality control wasn't on coffee break when these bolts were made!!!!!!! I always felt much better with the "old style" Vw bolts, the ones that after 650 miles you would back them off and then actually re-torque them to spec. Ok, I've rambled on enough about my "stretch-bolt" phobia! Hope it goes well for you and you don't need to pull the pre-chambers, although it's NOT a bad idea to do so , even if it's just to de-carbon the things. ( the 'ol scrub-ola) Cheers! Tom

There are three different thread sizes and pitches involved with the grooved nut/prechamber assembly.
First is the rather coarse internal thread of the nut, this what the injector screws into. Second is the coarse internal thread cut into the head. This is where the grooved nut screws in. Third is the fine thread cut internally on the prehamber itself. This is not visible with the grooved nut on place, but it is this fine thread that must be used to pull out the prechamber. I used a bolt to pull with rather than a slide-hammer because you can get much more force that way.