Here’s a horrible opinion

Trial & Error

Remember that injectors do not pop at the same pressure every single time. You have that “range” which could be up to one BAR or a little more

Second, there’s an old flame war regarding balanced injectors. FSM says +/- 50 PSI which is 3+ BAR

That’s five BAR alone.

I would experiment in increments of 7 or 8 BAR

So, 115, 123, 131 assuming the above. Obviously the tighter the balance and less flutter in your pop range then slightly different but you’ll see the same pattern although different BAR settings.

On the practical side, OEM shims are stepped .05

It has taken me years to get 3,000+ shims. Getting shims thinner would make McMaster Carr happy.

Rule of thumb is .05 = 3 BAR

That sounds perfectly reasonable.

It’ll be a build that happens in stages. A few things I need to learn along the way…

__________________
1981 240D 4sp manual. Ivory White.

Look at my thread “Will the real Hans Gruber please stand up”

I tried to remove all engine parasitic drag: VP & water pump delete; manual steering

Modified intake and turbo air filter

If the car ends up road worthy and ok to drive I will swap in a 5 speed and 2:88 differential

Then I will pop in the #242s and see if I can brake 100 mph

Weather has stopped my project, either too cold or it’s raining

“Will the real Hans Gruber please stand up” –Great thread

OM616 –meant to ask, what are you using for intake/exhaust manifolds?

__________________
1981 240D 4sp manual. Ivory White.

Were you able to determine how much metal remains after you machined that shoulder to accommodate the squirter? Also, is there a way to replicate your results easily since this appears to be the major missing piece when it comes to turbo-ing an OM616. I do not see a way to easily do an oil pump mod. An external sump pump like the 6.9 would be possible, but those costs are insane and the gains are about zero. Rather, trying to use current OM parts, although from different models, seems the easiest way to go.

The new cutter inserts came in Saturday along with some short drills I need to get in under a couple of the mains but one of the drills was labeled wrong and was too small diameter. I kind of want to finish this cylinder and make sure the dimensions are still good before I move on to the 3rd cylinder (which which requires the most material removed and is the one I am most concerned about wall thickness). The correct drill is coming in Tuesday. Once I have confirmed this cylinder is good, I will cut the 3rd one and see how the new inserts do and how much wall is left.

I still have to make shim plates to lift the squirter up and I am considering machining pins into the plate that plug into the block and leave the squirter pins alone as they will plug into the plates. As machined, the current pads are .100 to .120 inches lower then the 617a squireter pads.

Once I am confident that I nothing needs to be tweaked I can send you a drawing. All feature dimensions are referenced from the center of each cylinder and the bottom of the block. A custom cutter will have to be made to allow removal of metal below the main bosses. Also the lower right hand holes (for the hold down bolt and a dowel pin) are just about below the main. Even with a ER11 holder I still need a screw machine drill to get low enough to get the holder nut under the main boss on some of the cylinders.

Regarding the oil pump, I have not looked at that yet, but what I want to see is how much room there is between the pan and the pick up. As I recall the pick up just about sits on the bottom of the pan. A common practice to increase volume with OEM pumps when upgrades are not available is to make a spacer to put between the pump body halves and install longer rotors. I want to see if I can put the driven rotor of a 617a pump in a 617NA pump housing and EDM the bottom off of the 617a drive rotor and put that under the 617NA drive rotor making a 617NA pump with the same size rotors as the 617a pump. Then I would make a support collar to reinforce the end of the drive shaft. That is on the list to look at.

A good machine shop would be able to machine up the block.

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Oh wow. Impressive

Right now it’s incredibly cold outside or I would be rummaging in my crawl space for some extra squirters to send you.

I’m about one day’s worth of wrenching away from having a fully functioning cooling system, air intake, and charging system done. At that point its brakes and some sheet metal for the floors

I’ll track down some extra cores to build a set with the #242s.

If you can figure out some marketing ideas I’m game for a production run of 500 nozzles (#242s)

It is miserable cold here too. I have a bag of squirters that I have acquired over the past few years, more then I need, but I appreciate the thought

You are going to need some though

Sounds like you are really close!

I have a dumb thought-
If wall thickness is the limiting factor, would it be possible to mount slightly elsewhere which would require a “shim” to serve as a super thick gasket. Something tells me wall thickness is variable in the casting. The hole bore is probably pretty small compared to the mounting bolts or pins.

Not dumb at all. My plan B is to make a banjo type squieter that only requires a bore large enough for the ring, and it could even be installed at an angle so it wouldn't require boring into the side of the block. I have seen some MB squirters from some other engine that probibly could be made to work.

The block looks like they had "banks" of cores, one for each cylinder, that they stacked up next to each other. The #3 cylinder has a very large wall offset that will require the most material to be removed and is where i am concerned about the finished thickness.

The correct drill bit came in and I finished the #2 cylinder pad and it looks good. The next step is to put a 617a piston in the holes and varifiy the spigot fits into the piston properly.

With the second pad done, I thought I might as well ruff in the 3rd and check the wall thickness. I found that the thrust bearing main requires a smaller diameter shank on the cutter so I could not finish the inner features, but I was able to cut the side wall portion of the pocket.

The outside of the block in that area is very pocketed with some stud bosses and pockets under the oil gallery and there is one area, a corner really, that is the thinnest and that measured out in the .150 to .165 inch range. Sitting here thinking about it I did not check to see what the stud boss was for... could be a motor mount or accessory. Personally I am comfortable with that wall thickness in that area.

One pic is of the second pad and the other is of #1 and #2 installed.

I also took apart the 617a oil pump and removed the rotors. I need to get a 617NA pump to see what I can do with it.

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Great progress!

Half way done !

Also meant to ask you, what are you doing for nozzles these days?
Seems like monark, bosio, even Firad are NLA.

All I can find are bosch (likely, india) and ali-express style knockoffs.

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1981 240D 4sp manual. Ivory White.