Long time lurker, slow learner.

[Lincolnman]

Hello, all.
I figure that I ought to start with an introduction post here. I am a member of a number of forums, most of which I visit infrequently when I need specific information about a particular vehicle. That said - this may be the first forum I have ever joined specifically because I had to learn from it. I am not used to not knowing a fair bit going in, and so Megasquirt has proved to be more than a mental challenge to me.

So - here's the basic parts and concept overview. All parts mentioned are already purchased.
Vehicle - 1973 Lincoln Mark Continental Mark IV http://en.wikipedia.org/wiki/Lincoln_Co ... al_Mark_IV
Engine - Mercedes Benz M120 http://en.wikipedia.org/wiki/Mercedes-Benz_M120_engine
ECU - MS3X V3.57 and JBPerf 4 Channel board. http://www.msextra.com/forums/viewtopic ... 34#p313034

Currently the car is still in running / driving condition with the original 460 big block. Then engine was a (supposedly) low mileage pull out from a crashed car. It is the earlier version (pre-1995) and missing the distributor caps and rotors. At nearly $500 to replace them, I will be going to LSx truck style coils. (I have a bunch of those engines laying around, anyway to donate coils.)
Eventually I will build my second M120 engine to be fitted with dual Eaton superchargers (for hood clearance issues I have to go to two splayed out), but as of now I just want to get the stock M120 running in full sequential with the VVT working. The MS3X, on the other hand, is currently upstairs in a disassembled state awaiting my learning how to use it properly.

I have been reading, then reading, then reading some more but nothing is sinking in. I guess I just keep glazing over as I go through it. I think there is a possibility that I have the unit figured out for anything up to a V8, and may take a chance by fitting a MS3PRO to my 1979 KZ1300 since that would be much simpler than the V12, but I have not pulled the trigger on a second unit out of guilt for not yet using the first.
As of this exact moment I am not even asking a question, I guess - just introducing myself.
Any thoughts, criticisms, or brand bashing is welcome.

[Matt Cramer]

Welcome! That sounds like a cool project. I considered putting a German V12 in my '72 Chevy pickup when I found the 350 had a cracked block. But I wanted to get it back on the road quickly, and the level of documentation available for an LS swap tipped the odds in favor of a later truck motor. Got any pictures of the project?

[Hey_Allen]

I've seen a few people consider the M120 in older MB's and still turn to LS motors due to information available, and the sheer expense of playing with M120 engines.

Well, the expense, and the fun of the biodegradable wiring harness issues that MB had through those years. Having the throttle by wire secondary throttle valve drop synchronization with the cable activated primary valve made for interesting reading, but I wouldn't want to be the one trying to drive the car when it happened.

I'll be interested to see how it works out though, and wish you the best of luck and the least drama in this project!

[elaw]

Have you read this yet? http://www.msextra.com/doc/ms3/v10_v12.html

The easiest way to do ignition would be to run wasted-spark and just use 6 spark outputs, each driving two coils. But that manual page does tell you how to get 12 spark outputs.

Injection-wise, you could run batch-fire, or use the instructions there to add 4 injector outputs, using the board you already have.

Do you know what the crank/cam trigger arrangement on that engine is? Depending on the specifics, that can be pretty easy or pretty challenging.

I love Hey_Allen's term "biodegradable wiring"... I'm gonna have to remember that! It sounds like if you're going to Megasquirt the Benz engine you'll want to use all your own wiring. The motorized secondary throttles I'm sure can be dealt with via a creative mechanical solution.

[Hey_Allen]

I know that there is at least one benz forum with a tutorial on how to rewire the harness powering and linking the two throttle bodies. It looks like a bit of a pain but nowhere near as involved as a MS harness from scratch. It's just a bunch of pull wire, replace wire, and make sure you got the right wire.

If I were working on the S600 that the m120 came out of, I would be having much more concern, as if the engine harness was breaking down from heat/oil/whatever, you're also looking at other wiring near the engine breaking down. I heard rumors of at least one car fire caused by the insulation breaking down.
Since the OP is planning to use it in another car, at least he should be safe in that regard!

[Lincolnman]

Thanks for the responses, guys. I was a little worried that I might hear crickets chirping after posting.

But I wanted to get it back on the road quickly, and the level of documentation available for an LS swap tipped the odds in favor of a later truck motor. Got any pictures of the project?

Oh, yeah - the level of documentation on any small block Chevrolet is unending compared to basically anything else if you are talking about the United States. I wanted the M120 because it was the best V12 I could afford. I had considered Jaguars and BMWs, but they had their own drawbacks. I definitely did not take on this project with quick, easy or cheap to finish in mind. I don't have any pictures of anything right now, really. It's all just parts and an old Lincoln sitting in my storage unit at the moment. I might snap some later just for kicks, though.

I've seen a few people consider the M120 in older MB's and still turn to LS motors due to information available, and the sheer expense of playing with M120 engines.

Well, the expense, and the fun of the biodegradable wiring harness issues that MB had through those years.

Yeah, if a person is going to do a V12 in anything that it did not come in they have to do it for the sake of having a V12. There are much simpler, cheaper and more powerful options out there. The old saying about fast, cheap, easy - pick two? You can have all three better by not using a V12. For me, it's a mechanical love thing. (Does that sound weird?)
Totally right about the wiring, anyone curious about this should check out the site http://badmercedes.com/
Also, I am going full mechanical on the throttles, not messing about with that over engineered stuff they used. A V12 is more of the same parts and therefore not much more complicated than a single cylinder of the same design. Going from mechanical parts to electromechanical parts, though - that is different story. (Let's not point out the VVT or injectors for the sake of argument.)

Have you read this yet? http://www.msextra.com/doc/ms3/v10_v12.html

The easiest way to do ignition would be to run wasted-spark and just use 6 spark outputs, each driving two coils. But that manual page does tell you how to get 12 spark outputs.

Injection-wise, you could run batch-fire, or use the instructions there to add 4 injector outputs, using the board you already have.

Do you know what the crank/cam trigger arrangement on that engine is? Depending on the specifics, that can be pretty easy or pretty challenging.

I love Hey_Allen's term "biodegradable wiring"... I'm gonna have to remember that! It sounds like if you're going to Megasquirt the Benz engine you'll want to use all your own wiring. The motorized secondary throttles I'm sure can be dealt with via a creative mechanical solution.

I have read it, many times. I am slowly getting a handle on the basic idea, but that tutorial was not written for my hardware. Most of it translates, just not directly. I have Jean's V2.0 board, rather than the initial iteration shown there. Trust me, I will probably read those pages a dozen more times and skim them a hundred or more before I finish. Before purchasing my MS3X, I read every page that I could find via Google for V12s with Megasquirt. Most of it was not helpful or people saying "hey - neat idea here..."
I am debating running wasted spark and batch fire initially then changing it over later when I have a better handle on it, but I have not quite decided on that route yet. I have been too busy parting and crushing cars lately to do much but research, anyway.
I have not read into the factory crank and cam triggers, yet. If they prove to be too exotic, I will fit different ones.
All the wires will be new - none of the garbage that MB should have recalled for me, thanks.

I know that there is at least one benz forum with a tutorial on how to rewire the harness powering and linking the two throttle bodies. It looks like a bit of a pain but nowhere near as involved as a MS harness from scratch. It's just a bunch of pull wire, replace wire, and make sure you got the right wire.

If I were working on the S600 that the m120 came out of, I would be having much more concern, as if the engine harness was breaking down from heat/oil/whatever, you're also looking at other wiring near the engine breaking down. I heard rumors of at least one car fire caused by the insulation breaking down.
Since the OP is planning to use it in another car, at least he should be safe in that regard!

I am a member of a couple of Benz forums, and have seen some tutorials on how to rewire them. I plan on ditching almost everything that would have been affected, though. I know the harness will be a pain, but hopefully it is worth it when I get it running. On that subject, I have been thinking of welding up a running cradle for it so I can wire it out of the car and test it as such before the install. Anyone ever done this? Was it worth the extra little bit of effort?
As for the allegation of the wiring causing fires - it's true. It also lead to a disgustingly high number of early destruction and I think significantly damaged MB's previously stellar record. Think of it this way - the harness grounds out, the injectors run full on, and the cylinders get washed out. This on an unlined (Alumisil) aluminum block. Now you need a new short block - a mere $52,000 from Mercedes. No big deal, right?

Anyway - thanks again for the responses, guys - I will try to put together some more information, pictures and 10K foot view of the plan of attack.

[Hey_Allen]

As to welding up a frame to mount the engine, I found a simple engine stand from shucks a few years back that I was able to secure a MB m117 engine on.
I had to flex the frame inward a little bit to get the bolt holes to line up with the mounting points on the engine, but it's set stably on the stand for a few years since I pulled the blown motor out of my SEC.

You may be able to find something off the shelf to do what you want, without having to custom fabricate it.
That said, if you want to take the time to replicate the motor mount geometry just to have the stand cradle the engine in comfortable and familiar surroundings, who am I to tell you otherwise.

[Lincolnman]

Oh, I have a couple of engine stands of the traditional type that hold the motor from the back side bell housing bolts. I was asking if anyone thought that it would be worth the time to make a stand in which one could run the engine and get it up to temperature for setup and testing purposes?
Something like this -

[Lincolnman]

Has no one ever had a stand like this to set up their engines and test them prior to install? I would like to hear some insight from anyone who has...

[jsmcortina]

I have my test engine on a regular engine stand and a chain attached to an overhead beam for extra safety. That looks like a nice setup, the radiator mount on mine is a pain.

James

[Ollie8974]

These test stands are nice, for the one time engine builder they are a bit much. Do like jsmcortina suggested use an engine stand.
For a shop yes they are nice.
http://www.easy-run.net/default.aspx

[Lincolnman]

I am just digging this up again because I am starting back into the project. Recently I began thinking about it again, prioritizing some of my car projects. I made a new year's resolution to "simplify" my life. This means letting a lot of the car stuff go - but not the Lincoln. (Never the Lincoln.)

Anyway, I started reading about the engine some more to try to determine what sort of cam sensor that it had and where it took signal from. As it turns out, though I do not have the distributor caps or the rotors, I have the base of it (I think Mercedes calls it an "intermediate gear" or something vague and silly). The cam sensors, however read off the base and so I should be able to get signal just fine when I can determine what sort of signal they generate. I am not even sure if they are Hall sensors or something else. They are listed that way on some parts website, but I fear that they may use it as a generic term. From what information I have managed to gather so far I think I have a multi-tooth wheel with a flying magnet and what appears to be a two wire sensor. That is about as much as I know so far.

So then I got looking into the ignition buffer listed in the manual, and later realized that JB Performance had updated their board when I bought mine and the manual is referring to the old style, so all the junk I bought for making the buffer units is now useless because they are already built into the add on board. I even knew that, but had forgotten.

I have decided to weld together a running stand, when I am done with it I am sure that my friend will put it to good use, as he builds about two or three motors a year. It should not be too hard to make it fit multiple engines, just knock together some mounts.

Anyway - that is the update.

[elaw]

If you could post some photos of the cam sensors and whatever triggers them we can probably provide some input. Also how many wires connect to the sensors. If it's two, they're almost certainly VR sensors. If three, they could be Hall or VR - their appearance may tell. Of course if you have a wiring diagram for the engine that would probably tell you too.

[bradyzq]

I looked into these M120 engines for a fantasy build (don't have car or engine) I was dreaming about.

Remember what you paid for this contribution and value it accordingly, but I think the crank trigger is a 60-2 wheel with 2 VR crank sensors offset by 60 (I think?) degrees. With MS3X, you need only one of them.

For the cam sensors, they should be Hall effect half moon or shorter single tooth, but again, you need only one, or none actually, if you run wasted spark and batch fire.

Cool idea to bring back the V12 Lincoln! Carry on.

[Lincolnman]

If you could post some photos of the cam sensors and whatever triggers them we can probably provide some input. Also how many wires connect to the sensors. If it's two, they're almost certainly VR sensors. If three, they could be Hall or VR - their appearance may tell. Of course if you have a wiring diagram for the engine that would probably tell you too.

I do not have the distributor's "intermediate gear" out to show the trigger side of it, and I have been having a lot of trouble finding a picture of it online. I hate to remove it, lest I disturb something that I will have to try and set correctly again later. It appears to have two wires (one center pin and one outer connection), so that made me think VR.
Here is a shot from a parts website showing the type of sensor.

On the other hand, when looking for them online I found them listed as Hall effect on another site, but I do not know if the site that listed them that way was using it as a generic term for any camshaft position sensor, or even if they were referring to the later years unit. From what I can tell, they changed the style from the early M120 to the late M120, but from what I do not know...
I bought a "full factory repair manual" dvd from eBay at one point for like $40, but it was a complete scam. Unusable files for horribly outdated software, missing information, you name it. So I do not have a whole lot to use for reference.
I have read a couple of places that said that the sensor generates a pulse which increases voltage with RPM, and that makes me think that it is a VR.

I looked into these M120 engines for a fantasy build (don't have car or engine) I was dreaming about.

Remember what you paid for this contribution and value it accordingly, but I think the crank trigger is a 60-2 wheel with 2 VR crank sensors offset by 60 (I think?) degrees. With MS3X, you need only one of them.

For the cam sensors, they should be Hall effect half moon or shorter single tooth, but again, you need only one, or none actually, if you run wasted spark and batch fire.

Cool idea to bring back the V12 Lincoln! Carry on.

Correct, the crank trigger on the later M120 engine is a 60-2 on the ring gear, the earlier units (like mine was until I bought a later ring gear) have three slightly wider equidistant tabs on the ring gear. Also, yes there are two crank sensors offset by 60* on the backside, plus an additional crank sensor (or so I am told - I have not looked) on the front for diagnostic use only. I know there are for sure the two on the back, not sure about that third one...
I want to run full sequential, so that is why I am looking into it.


I do have some information from the MB forums, if anyone can make something meaningful of it.
One of the members was good enough to post a couple of pages from their repair manual, though they felt it was probably not much help. I see what looks like a flying magnet trigger multiple teeth trigger wheel, and it is listed on another page as Hall Effect, though again - that may or may not be for a later year... That said, I think that the later units were exactly the same, just without the integrated lead wire.
On these pages the engine is listed as M120, 120, M104, or 104. The M104 is the inline six cylinder version of this motor, pretty much the same exact thing, but they added another bank for the M120.
http://i.imgur.com/Vs92zwE.png
http://i.imgur.com/TIwIiGT.png
http://i.imgur.com/OjE8al5.png
http://i.imgur.com/D5AUJML.png

I will add more as I dig through the latest help from the other forums.

[Lincolnman]

A two wire Hall effect THEORY from another forum - has anyone heard of such a thing?

Quote:
Originally Posted by oldtrucker

"What I write here is pure therory and don't quote me on it.
Also, I have little to no experience with this engine type.

If I had my fingers in the design, I would use a hall effect sensor. sort of a transistor that I can switch on and off with a magnet.
This type would require some voltage to be applied.
The induction sensor is probably not the way to do it, since there are other sources of interference that could lead to misreadings. Also, an inductor has the disadvantage to generate a negative pulse and Voltage and Current are out of phase for a brief moment every time it gets triggered, causing unwanted harmonics (Interference). It can be knocked down, but in a vehicle, we don't want to overdo it, if there is a better solution.

The cam shaft has probably teeth or magnets (magnetized theeth number depends on how accurate it needs to be) at the end with one of them being slighty larger than the rest of it.
This would allow for a start position sense and then in conjuction with a fixed number of pulses, the exact position of the shaft could be determined by counting the teeth from the start pulse.

With a two wire design, the actual wire could be the supply and signal wire at the same time.
Physically, I can see a coaxial connector, center signal/supply and the outer is possibly a shield attached to chassis or computer ground.
The device that receives the signal is probably "low active" meaning there is a supply voltage as soon as the ignition switch is on. As the cam turns the teeths on it will pull the hall receiver to ground, meaning it is active. if a non magnetic part matches the Hall sensor, the voltage will rise to whatever supply it is, and so on. The slightly longer active time (low) will determine the start position of the cam. Now there is most certainly more involved, but I think that is the pricipal of the beast.

The distance between the magnet and the Hall is important."

[bradyzq]

Considering that's it's a Bosch EFI (well, 2 of them) from the 90's, it's probably a Hall effect on the cam, as it says on the M120 parts layout pic.

From the component pics, it looks like the cam sensor, with bare metal exposed at the bolt hole, may be grounded through the engine, negating one wire. And the magnet is usually in the sensor.

Gotta run.

[Lincolnman]

Aw, jeez.
Why had it not occurred to me that the bolt hole was probably a ground?

[Lincolnman]

Wait a minute - can I actually use engine as a ground for MS? I seem to recall that was a no-no for some reason like noise or such.

...or will I need to run a wire from the mounting ring back to the MS?

[elaw]

The first two docs you posted clearly describe a VR sensor. Indications are that the sensor signals ("h" traces) have a sharp positive then negative spike, and the fact (on the next page) that it states the amplitude increases with RPM. Hall sensor outputs are square pulses (they go from 0 to a specific positive voltage, stay there for a time, then go back to 0) and their amplitude doesn't vary with RPM.

They also just look like VR sensors, and the # of wires points in that direction too. It's possible the wire shield is grounded to the block, but for one of the actual sensor wires to be grounded to the block is very unusual, especially if it's a Bosch system.