High tech injection system for the 616, 617
 

I have been pondering the idea of a kit to convert the old diesels we love to a high tech injection system such as is used on a modern diesel. I am wondering if it is feasible to come up with a system that bolts into the hole our mechanical injectors use and so forth.

Imagine, a 45 mpg 240d with more power and less smoke and noise.

Tom W

we discussed this over at schumans.... its a pipe dream with a massive price tag

In the past you had a good chance of finding out what was wrong with your (gas) car. Now so much electronic stuff has been added it is difficult to trouble shoot them with out special analyzers or taking it to someone to trouble shoot.
While it is true that mechnical fuel injection systems are expensive when they need to be fixed; if the system is kept clean they are not troublesome and there are proceedures you can follow to find out what might be wrong.
In an envornment of heat and vibration electronic components do not hold up as well as mechanical ones. Not to mention it will take special testers to check out these type of systems. As an example of cost I just looked on Ebay one Ford Powerstroke diesel injector is $99-$139 each; an injector drive module $159-$249 and so on.
I would rather put up with my old fuel injection system then have one that I cannot trouble shoot without buying alot of expensive testers or afford to repair.

This is one of those "do it because you can" projects.


If you want a CDI 240D, which would be a what? E240CDI?:D Its possible...

1. Get a nice 240D with a blown engine, that shouldn't be that hard to do.
2. Find, somehow, a 4 cylinder MB CDI engine, with all the computers that are needed to make it run. You will probably also need transmission.

3. Place CDI engine in the 240D, which is the simple part. Now hook up the computers and get it to work.

http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/178997-m120-into-560sl-pictures.html

While a different engine and car, thats about what you are going to have to do.

Let's see. You can buy a high pressure belt-driven CP3 pump for around $3000. It'll come with some soft and hard lines, and you can probably make or have fabricated your own common rail for a few hundred dollars. After that it starts getting expensive. I don't think there are any common-rail injectors that will fit the OM616/617 head, so you could either modify (most likely design and build a completely new one) head that takes an available injector, or design and build your own injectors to fit the head. I'm thinking a new-from-scratch head would be cheaper and easier. If you're good with design and have previous experience in internal combustion cylinder head design, you could probably come up with a working design in a month or two, less if you bang away at it full time.

Then you have to get someone to manufacture the head for you, unless you have a sufficiently good home shop to do it. With CNC, this is a lot less expensive for a one-off than things used to be, but I'd still expect to pay over ten grand for one head.

After that, you'll need to come up with some sensors, an ECM, and a fueling strategy. You could probably make it run with just a TPS, and a cam position sensor, but to come up with a really good fueling strategy, you'll need to be able to measure exhaust gas temperature and manifold pressure in real time, at least for R&D. Since you don't have to deal with the EPA, you'll have a much much easier time with your engine program than the OEM's do, but it's still going to be a lot of work to get it running the way you want.

So, short answer to your question, yes it can be done, but the cost in time and money would probably buy you a new Bluetech (at least).

Modern diesels use direct injection. A 240d uses indirect injection. Totally different cylinder head design. No pre-chamber with a DI engine.

It would be much easier and a lot cheaper to just swap an entire 220 CDI motor in. 45 mpg's and 170 hp from a 220 CDI motor, BTW. ;)

It would be nice to at least know if the newer engine could be swapped into the old 240s. Eventually they are going to turn up from car wrecks.
It is probably a given that the transmission has to go in as well. Maybe the rear end too. If a guy had access to all components of a wreck it might be doable. Are you ever going to need a shop manual for this one Tom. :D
It is still the best way to modernise the injection system if everything can be squeezed in there. Should kill a weekend easily. :)

About three and a half days, right?

Tom W

Awwwww, you guys are no fun!

Tom W

You know, though...
A Blutec conversion kit (all the bits to make the new engine fit and work) in a 123 chassis would have a reasonable chance of selling...
How much is a crate motor and crate trans these days?
-nB

This idea is not so far fetched. Before you hang me, let me explain. Here is what I am pondering. I know many guys with gas vehicles that need to run stand alone fuel injection systems. Why couldn't we do that with a diesel engine? I know that a mega squirt can be used to run fuel only ( not spark ) , all it needs is a tach signal, so the control unit knows where the engine position (timing) is. you might need a crank and/or cam position sensor and maybe a manifold air pressure / vacuum sensor.

So , quickly thinking about it, we would need:
The stand alone engine control system.
electronic injectors
electronic fuel pump(s)
Fabrication of a fuel rail, maybe injector adapters, maybe a toothed wheel for the crank
Wires, etc.

you would ditch the factory injection pump, lines and injectors.
the electronic fuel pump(s) would feed the fuel rail,
you would take the tach signal ( crank/cam sensor signal ) and the MAP sensor and feed it to the control unit.
then the control unit would send a signal to open and close each injector.

Its that simple. the only thing is that you would have to program the fuel map.

This would open up a world tunning options.

A quick search on ebay for "stand alone diesel injection" and I found:

http://www.nexumresearch.com/Commonrail.html

http://www.mwfi.com/fass/fass.html

the second link shows that these are replacements for some vehicles, but the idea is the same.

this is just a quick idea I gathered in 3 minutes while I posted this. If we think about it for a few days and research it, I think it could happen. BUT it would have a price tag, probably somewhere between $500 - $1000, However the benefits would be great. This would be great for people would want to run crazy boost levels since you are directly controlling the fuel delivery.

Doesn't Tempo in India do something like this already? Don't they have a direct injection version of the 616???

It wouldn't really be a direct injection system as the prechamber would not be eliminated. thats the hard part and really not all that necessary.

I'd totally swap a 220 CDI engine into my 240D, with a new transmission...trouble is I don't know where to get one from.

Well, now there are some possibilities!

The one system apparently is already being marketed, but at $7000 the payoff would be pretty long!

I am not sure a system like megasquirt, designed for gasoline, would work for the heavier viscosity diesel fuel.

Tom W

Megasquirt is a computer system, not an injection system.

As Forced said it is a computer not an injection system so there is no such thing as megasquirt injectors, etc. Still, megasquirt is designed for gas engines, which do not need precise timing on injection events. You just spray a bunch of gas into the intake (or in front of each valve if you want) and you're good to go. A diesel wouldn't run too well that way. ;)

See my other post about Megasquirt... There is no way that it would work for a diesel. Totally different beast. Also, there should not be any vacuum on a diesel's manifold, but if there is boost pressure you would need to know that.

The most realistic way of accomplishing this is to use the normal injectors, but with some kind of electronic valve to control it with a common rail supplying the pressure. This may sound simple, but keep in mind that our injectors need 145 bar, and you have to have timing that is precise to within microseconds (.000001s). Until you find that.... nothing is going to happen.

The second link is not a standalone fuel injection system. It also seems like a snake oil product. The first link costs $7,000 for a ONE CYLINDER engine. It is targeted at research labs trying to research engine designs, etc. Not a road worthy vehicle.

If all the parts do actually exist (injector valves, etc), the fab work isn't all that expensive, and somebody designs an open source (or cheap) common rail controller you'd be looking at $3k easy. It *would* be great for lots of tuning and performance mods, but you'll still have an engine that gets crappy fuel mileage relative to modern direct injection diesels.

I don't mean to rain on your parade, but the cost makes it very hard to justify. IMO, the best way to have a computer controlled IDI diesel is to use the injection pump off of an OM606 (won't work on OM616 or OM617 diesels though). It has an electronic fuel rack... that way you can control the amount of fuel, without having to worry about all the injection timing events, and gobs of custom fabrication. :cool:

I think so. The problem with converting to DI is there is a different piston and head design. After replacing those it might very well have been cheaper to put in a used DI engine! :(

another obstacle is compression ratio on these cars. DI ratio's are around 14:1, where our IDI CR is around 22:1. so is this plan to just computerize the existing IDI injectors, or to upgrade to DI injection? cause I don't see computerizing IDI as much of an improvement. and I don't see DI working at 22:1 CR... so you are talking about not just redesigning the injectors, you are talking about redesigning the piston and head dome... um. not really possible, but if you think STOCK 616/617 pistons are pricey... try one off pistons...

Well, this is good information.

Not what I was hoping to hear but good information.

I am interested in Gurkha weighing in with the Indian connection to advances relative to the 616 617.

Tom W

On the Mercedes side of things...

The OM 602.98x was Mercedes' direct injection version of the OM602.9x. Introduced in the 1996 E290, Sprinter and Unimog it used a rotary injection pump and an intercooler. Power was mostly the same.

Compression ratio has nothing to do with DI vs. IDI. Nothing. VW TDI motors are direct injection and they operate at 17.5 to 1. The C220 CDI operates at 18:1.

The reason for the slightly lower compression ratio is the increased turbo boost. The newer engines run much higher boost, hence the reason for slightly lower CR. For the same reason, a normally aspirated diesel motor will have a CR that is higher still.

Looks like a less complicated swap. Good luck trying to get one in this country, you would have to import it.

hmm, so power was unchanged in this powerplant, was efficiency improved?
if the CR is different only for added turbo boost, then it's the boost that gives the additional power, not the DI/IDI thing... so... if we put a thicker head gasket on our 617's added a bigger turbo for more boost, and enriched the fuel... would we get a big boost in power without the danger of high EGT? ... HMMMMM

No, you would have lower power and reduced efficiency because of the reduced squish area between the head and piston. If you want to lower the compression ratio you would have to machine out the bowl of the piston.

Converting to direct injection would involve a new head and pistons at a minimum.

However, convering the existing indirect system to common rail injection seems a lot less involved. Need feed pump, sensors, switchable injectors, computer controller and common rail (manifold).

Is this more what you had in mind Tom?


Also, any possibility the existing IP could be used as a feed pump -- disconnect throttle & ALDA and wedge in WOT? That would make playing around with the idea a lot less involved and potentially easily reversible, provided you din't blow up the engine :)

What would be the advantage to converting to common rail?

Want more power? Turn up the pump and/or install larger plungers.
Want better atomization? Shim the injectors to a higher pop pressure (Like mine).
Want a different spray pattern? Install different nozzles (Like mine).
Want multiple injections (pre-spray) from the injectors? Use 2-stage injectors (Like mine).

There wouldn't be any advantage to building a common-rail system to fit an old inefficient engine like the 617. In the end, it would still be far cheaper to buy a wrecked sprinter and transplant the drivetrain.

Yes, I was thinking of using the existing heads and pistons and just contolling the injection process better. I am not kowledgable about the idi di question.

Tom W

My neighbor's buddies planed the head down on one of their gas engines to increase the compresson ratio. They got it up to around 11 to 1 (and no, they can't run normal gas in it anymore).

I'd think piston head changes and changing the distance between the head and block would be equivalant compressionwise. I find these littel nuances facinating, so if you have any pointers to further reading I can do to educate myself on why not, I'd really appreciate it.

I think machining out the tops of the pistons is out. They really aren't all that thick to start with.

Tom W

Planing the OM617 head would not do anything, the head is a flat surface except for the prechamber poking out. Most g@ssers heads have a combustion bowl in the head. Machining their head reduces the size of that chamber and increases compression. The OM617 head is flat so you would just be reducing the thickness of the metal.

Compare. HEMI on the left (the same type the 280E is), OM61x on the right.

http://vegburner.co.uk/DIcombustion.html

Shows what a DI piston looks like. Has a deep "bowl" in it vs. an IDI piston which is relatively flat on top by comparison.

There's no way you can machine that bowl into an IDI piston. No way, no how, it is not possible. So forget that idea.

You could have some custom pistons made up, but then for the same $$$$ you might as well do a full CDI engine swap - much easier and you know the engine is going to run. ;)

The key to anything like this is availability of parts. Sure you could import a complete MB CDI drivetrain from Europe but at what cost and who would work on it to figure out codes, etc. when things go wrong. And they will. The next option is to consider a swap from an available chassis here in the US. There have to be some wrecked E320 CDI's around. Is it possible to swap that entire setup? Or a Sprinter setup? I've even heard told of guys turning VW TDI's 90degrees and bolting them up to regular RWD transmissions.... Focus on what is most available and go from there. RT

What about a VW TDI engine then? Thats probably the most logical choice if someone wants to make a more powerfull 240D. With some mods you can put down a lot more power than any 617.

Thats a good point. Of the 1.9 TDI's here in the US, the 1z and Ahu motors have minimal electronics and are popular for use in swaps.

Over on TDIclub.com there's an "engine swap" forum and currently someone is putting one into a Saturn, and someone else has put one into a Volvo 240.

You'd of course be looking at some custom fabrication for things like motor mounts, exhaust, and bell housing adapter for the transmission.

Well it depends how mechanicaly inclined you are and how big your shop is. You need to have the skill and will.

There was someone on here a year or so ago that was trying to wedge a vw diesel into a 123 td, iirc. He had it sitting in the car iirc but it looked like he was headed for trouble as some of the details weren't quite worked out yet. (the infamous sump interference, iirc)

It seems he had the vw steeply tilted in an effort to clear sump and crossmember without cutting anything. I seem to remember he was headed for trouble on the gear ratio too in the rear end.

I wonder what happened to that?

Tom W

Has been done, Force Motors India which is a MB partner here sold their G Wagen clone called Gurkha with OM616 turbo in Germany. With latest BOSCH pump, it passed stringent Euro-IV requirments.

Is it feasible to transfer that technology to an old engine?

Tom

As stated before there is probably a new head, pistons, injectors, etc. So it is possible... you just have to make the financial decision of is it really worth replacing all those parts...

And as stated before, it would probably be several thousand $$$ cheaper to ship a crate engine over here than it would be to convert an existing engine.

Personally, I'd like to get one of those FM OM605's.

Force motorshttp://www.forcemotors.com also converted the OM616 into a turbo DI engine, they changed the pistons, cam, head and IP. It passes euro-III. Another Indian company Mahindra took an ancient Simpson diesel motor which they had the license to manufacture and made it into state of the art CRDI engine with help from AVL Austria. From a measly 38bhp engine the 2.6L motor now makes a nice torquey 115bhp. So with proper implementation of technology, it can be done.

Oh come on guys......just screw the 240 fenders on a new Mercedes Diesel....Problem solved. Dave :D

Don't think the new MBs can take the load of the 240 fenders :)

Yes, I understood the prevous post.

Tom W

As stated above I understood the previous posts which said you would have to change heads and pistons along with the other stuff.

And at that point it would be cheaper to replace the entire engine.

But it still seems to me a lot could be done with just a modern injection system installed on our ancient 616 or 617 engines, without changing the heads and pistons.

Tom W

I am pretty sure the Gurkha set up with the OM616 has nothing really elecronic in it.

A retrofit on the block and IDI head could be electro-mechanic. Timing is determinate by a wheel attached to the port of the pump. and in the same fashion than a distributor cap it sends directly a pulse to an electric injector on a common rail.
I am convinced this would not be a particularly hard set up to come about. No ECU just mechanical brute force like gasoline engine of long gone times...

There also a concept like this about valves control...

Absolutely correct, the Gurkha up to Euro-II was all mechanical affair, but with Euro-III and IV, it became electronic to meet up with the stringent requirments.