Anyone ever thought of doing away with the precombustion chambers on a 5cyl 126 diese

[bigchingan1]

I don't know if eliminating the porus piece in the precombustion chambers would increase the power, I know it would increase the noise Anyone ever tried this. Reason I'm asking is we have a few old engines of that type that I would like to play around with, see what type of power we could get out of them (remember the c199 I think it was, it was the same engine, highly modified that won the 24 hour race at le manns in the late 60s or early 70s)

Now thats some real tinkering please keep us updated.
Dave

[MS Fowler]

If I understand your question, you intend to remove the precombustion chambers? I do not believe the engine will run w/o the pre chambers. These are not direct injection engine; the pre com chambers are a necessary part of the process. They help to mix the injected oil with the heated ait and control the spread of the flame front. I do not believe removing them is an improvement. ( I bet M-B would have removed them if it helped)

They would have made it that way if it was better is often stated on this board. Well the way they made it was all give and take. They could have made it faster but it would cost more, would be too loud, hard to start poor fuel mileage, ugly. And so on and so on if you want just pure speed MBZ did not make that diesel but they could have and it would be very different then the one you drive. If you want fast ceramic coat your piston heads lighten your rods gasket match all parts put on fiberglass front end. Wouldn’t that be kewl hood and fenders lift out of your way when you want to work on it. If you want the way MBZ wanted it you better get one imported there way different than the models sold in the states. And finely the pre chambers do help mix the fuel.
My 2 cents Dave

you plug the space left by the precombustion chamber with something of just the right volume to produce a workable DI compression ratio.

You are kidding, right?

MB pioneered the diesel powered automobile and has done, by far, more research and development in this area than anyone in the world. Do you REALLY think that you can improve on their millions and millions of R&D Deutshmarks poured into all this?

If you are going to remove the prechambers, don't forget to pay attention to piston crown shape. This was carefully designed for the flame propogation caused by the prechamber, just as the new pistons in direct inject engines are designed for NO prechamber and take into careful consideration the injector location and resulting flame propogation.

If you have really deep pockets and are ready to embark on such an R&D campaign, please share your results with us.

Have a great day,

Originally posted by bigchingan1
I don't know if eliminating the porus piece in the precombustion chambers would increase the power, I know it would increase the noise Anyone ever tried this. Reason I'm asking is we have a few old engines

I'll take a stab in the air and guess you mean the ball pin(?) inside the PC?

(The yellow part across the PC below the glowplug.)



I still have to agree with the others that MB put countless hours into it's design. It would take countless more to make a reasonable (30%+) increase in power to make anything worth the time. (You could get that increase by making a swap with an OM603 and I'd bet that would be cheaper.)

[73MB280SEL]

One really wild idea I had a while back was to put a common rail injection system on an older indirect injection engine. Think about how quiet an indirect common rail engine would be.

Of course, I've also thought about a OM616 powered BMW 2002 or an OM616 powered lawn tractor.


Sholin (thinking creatively) in Mustang, OK.

How about a 300D turbo engine in a 240D body?

[psfred]

First, you are most likely to damage the engine by messing about with the existing system -- the reason the MB engine is so quiet and smooth is the design of the pre-chamber and injector.

You cannot use a waisted pintle injector on a direct injection engine, it will promptly burn a hole in the top of the piston. DI engines use side hole nozzles OR some other system of directing the flame into a diffuser of some sort -- on the CDI engines this is a steel insert in the piston that performs the fuctions of the prechamber (high swirl and flame diffusion).

Removing the ball pin will result in failure of the prechamber tip, with resultant engine damage from chunks of hardened steel roaming around in there during operation.

The prechamber and ball pin DO NOT reduce the power, they actually increase power, reduce noise, and permit higher rpm operation. They are there to promote even combustion for the entire injection cycle with longer flame duration. The holes in the tip both diffuse the flame away from the piston crown and set up a high velicity swirl in the pre-chamber that causes high mixing and efficient burn of the fuel during injection, etc.

You can do whatever you want, but you won't improve much on the MB design, and modifications to the prechamber (like removal of the ball pin) will give you running problems or damage.

Peter

wait what if i change it so TDC is a point where the piston lingers for a moment to achive a more complete combustion. Causing a more thru burn. Also I cermaic coat my pistons so they wont have holes in there tops from the injectors. Oh I cant resist has any one thought of using that funny engine starting fluid stuff for fuel real strong head bolts might work.
If you want a better diesel look at the amg. Or look at the truck sites lots of stuff they due you can do to a MBZ if thats what you want.
Dave

[Tymbrymi]

Okay, so taking the Prechamber out appears to be a nono unless a completley different injector is used.

So.... what about eliminating the IP and putting a common rail system that is controlled by computer? Or any EFI system? Dunno how hard it would be to get a Common rail system. There are a few junked sprinters already aren't there

This would be a good senior deisgn project for me and if its remotely possible I'd like to do it.

John
'79 300SD

[rickg]

Want more power? Leave it the way it is, and add on a propane system.

[DslBnz]

Originally posted by rickg
Want more power? Leave it the way it is, and add on a propane system.

I second that one....And get an ever-essential pyrometer.

That way you'll have enough power to get out of a tight situation, and can install a switch to shut off the external tank when you're finished with it.

You don't need 500 horsies on tap all day long. Most of us only travel between 65 and 95mph on the interstates anyway with the SUV's being at the higher end of that range(those things have 100mph limiters too! Which means that a few people keep their feet to the floor).

As far as I'm concerned, anything above 100 mph, in ANY car should be taken to the track. You endanger others as well as yourself.

Originally posted by rickg
Want more power? Leave it the way it is, and add on a propane system.

I like it but I would try nitrous first. That should be a more safe option with the precombustion chamber design.

Advancing the timing (The TDC idea) by 2-3* can make a difference. Remember to set it to the correct 24* BTDC FIRST. Chain wear may change it over time and messing with timing that my be 20* or 28* makes it worth the time. I advanced mine 2* about 4 months ago and it did make a noticable increase in low end and a small decrease in high end.