2 cycle out of a 4cycle? - Page 2 - PeachParts Mercedes-Benz Forum

pawoSD · #16 02-12-2008, 04:00 PM

I always wondered why those Detroit engines sounded so different. 2-stroke engines.....interesting. Ok, now I know they can run higher than 1000rpm.

Somehow I don't think its ever going to happen/work.

patbob · #17 02-12-2008, 07:56 PM

Changing to DI has been discussed.. you need a new head of your own design. So, $$$ If you do this, then you have a lot of options, and the below doesn't apply unless you want it to.

You''ll need a new cam that opens both intake and exhaust valves simultaneously. You'll need a supercharger so you can raise the intake air pressure to blow the exhaust out for the next cycle. You'll need the IP to pump twice as often.. I think it might work if you can run it at 2X RPM, but I doubt you could substitute a smaller sprocket to accomplish that. You'll use 2X fuel at all RPMs and you'll have to have a manual transmission as I doubt the torque converter & ATF could withstand converting all that extra torque to heat when stopped.

I like your idea of using a supercharger and turbocharger, but the supercharger will be partly pumping the turbocharger, which sounds difficult to control to me. Mightbe easier to let the supercharger change intake air pressure with engine RPM.

If you do this, certainly write back.. success or fail, I'm sure lots of people would be interested

Cervan · #18 02-12-2008, 08:25 PM

Quote:

Originally Posted by patbob

Changing to DI has been discussed.. you need a new head of your own design. So, $$$ If you do this, then you have a lot of options, and the below doesn't apply unless you want it to.

You''ll need a new cam that opens both intake and exhaust valves simultaneously. You'll need a supercharger so you can raise the intake air pressure to blow the exhaust out for the next cycle. You'll need the IP to pump twice as often.. I think it might work if you can run it at 2X RPM, but I doubt you could substitute a smaller sprocket to accomplish that. You'll use 2X fuel at all RPMs and you'll have to have a manual transmission as I doubt the torque converter & ATF could withstand converting all that extra torque to heat when stopped.

I like your idea of using a supercharger and turbocharger, but the supercharger will be partly pumping the turbocharger, which sounds difficult to control to me. Mightbe easier to let the supercharger change intake air pressure with engine RPM.

If you do this, certainly write back.. success or fail, I'm sure lots of people would be interested

Haha, Yeah it will use fuel, like a fiend it will drink that stuff. But you cant get something out of nothing right? (Thats one thing my father never understood, "Why dont you just bolt a turbo on there and get more power?"

) Anyways, before i start this project im going to finish my little honda project so atleast i have something to drive in the meantime. As for the thought on the supercharger moving the turbo, i was thinking of making a reverse VVT turbo. Closing the vanes at low speeds and opening them at high speeds. Of course there are two ways this can be done, somehow seal the turbo from the intake path at idle and low speeds, and then opening it up to let the turbo build psi. but then again.. if i just put a normal turbo infront of the supercharger.. maybie that will help it abit because it will allways be spinning (Maybie not very fast) But maybie it will account for the lost spool up time? and a supercharger is allways spinning because of the crank i dont see how it could hurt anything.

As for the injection pump and valve cam. Ill probibally try to swap the cam sprocket onto the injectionpump, That will make it 1:1 with the crank (Right?) And for the cams.. ill have to either get them machined and then metal added to them to make them what i want. or buy ones casted the way i want. (Yeash sounds costly allready)

The bottom end ill be building as well, ill get the crank microbeeded and knifeedged, the rods shotpeened and the cyilnders overbored .30 over with matching pistions (To get the tolerances perfect) Ill lighten the flywheel (Just taking the casting off of the rear maybie 1 or 2 pounds) Ah forgot, ill add pistion oil coolers (Along with a high pressure oil pump) Throw it back together and pray.

As for the head ill get stainless steel valves and a 6angle valve grind (So i dont burn the valves) Im really taking a chance with the precomb chambers.. im hoping that they dont cause any problems.. Hey forced, where could i find a VVT at?

Oh and the tranny is a stick with a new clutch so i should be good to go. (Reason im wanting to do this so badly is because final ratio went down on this year, meaning i cant hit 75 no matter what >.

__________________
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

Last edited by Cervan; 02-12-2008 at 08:31 PM.

#19 02-12-2008, 08:32 PM

Quote:

Originally Posted by Cervan

As for the injection pump and valve cam. Ill probibally try to swap the cam sprocket onto the injectionpump, That will make it 1:1 with the crank (Right?)

Cam and pump run 1:2 to the crank. You would have to put a crank sprocket on the cam and pump or a cam sprocket on the crank.

Making the pump sprocket smaller runs into the problem of compensating the loss of the timing mechanism built into the sprocket while a large crank sprocket would interfere with the oil pump.

You could always remove the pump and turn it into a dry sump.

Quote:

The bottom end ill be building as well, ill get the crank microbeeded and knifeedged, the rods shotpeened and the cyilnders overbored .30 over with matching pistions (To get the tolerances perfect) Ill lighten the flywheel (Just taking the casting off of the rear maybie 1 or 2 pounds) Ah forgot, ill add pistion oil coolers (Along with a high pressure oil pump) Throw it back together and pray.

Now you are getting into expensive one-off fabrication stuff. At that point you might as well drop the money into a SBC and out of the gate you'll have 2x the power you could ever squeeze out of a 616. Slap a turbo on that SBC and you'll have 6x the power of your ultimate 2-stroke 616.

Cervan · #20 02-12-2008, 08:42 PM

Quote:

Originally Posted by ForcedInduction

Cam and pump run 1:2 to the crank. You would have to put a crank sprocket on the cam and pump or a cam sprocket on the crank.

Making the pump sprocket smaller runs into the problem of compensating the loss of the timing mechanism built into the sprocket while a large crank sprocket would interfere with the oil pump.

You could always remove the pump and turn it into a dry sump.

Now you are getting into expensive one-off fabrication stuff. At that point you might as well drop the money into a SBC and out of the gate you'll have 2x the power you could ever squeeze out of a 616. Slap a turbo on that SBC and you'll have 6x the power of your ultimate 2-stroke 616.

SBC? What does that stand for? The reason for this madness, was because i love 2-strokes allways have wanted to have something diffrent, Maybie the bottom end can handle the extra stress.. i do have a free engine... (Edit) Ah, smallblockchevy Gotcha. Well i was planning before this to put a twin turbocharged 302 with a built c4 tranny into this very same car, but the two stroke idea grabbed my attention.

myssrhl · #21 02-12-2008, 09:07 PM

Man,

I have a MCI bus RV with the ole 2 stroke in it "I love it"..

Feels like electric power.

First one was a 8v71, now the new has a 6v92 w/turbo.

The 8v would pull off the line but the 6v will stroll down the hwy.

Yet if a supercharger seal blows you have a runaway that is as scary as 3 mile island.

Those darn would start if a mechanic turned the crank with a wrench.

Yet if you want power how about propane injection.

Buses us that to climb mountains.

Otherwise ......wheeeww...you are reinventing the wheel.

Those ole Detroit block like cheesecake with inlet ports.

I am considering starting a small block chevy project.
Build an engine / trany and be ready if she pukes.
If she doesn't put it in the 51 chevy p/u

Oh hell lets do it.

#22 02-12-2008, 09:18 PM

Get it over with and throw in a 3-71.

Or a 4-71.

Screw it, go all the way and use a quad turbo 12V149.

Hatterasguy · #23 02-12-2008, 10:02 PM

It would be cheaper to go just buy a CDI. You would have to re-engineer the block and recast the block and head.

Besides 2 stroke diesels sucked, I remember the old Detroits. Heck I got smoked by a tired 8-71TI in a Hattares 53 a couple of weeks ago. Loud smokey old things. Why would anyone want such an annoying engine?

One of the boats I fish off of has a pair of 6-71's which are super loud and annoying. You fire them off at 4am and they cover half the parking lot in smoke. Not to mention you have to shout at cruise, loud SOB's! I think he should repower with a set of modern Cummins or Volvo's. The new computer controlled engines are better.

Cervan · #24 02-13-2008, 01:29 AM

Quote:

Originally Posted by Hatterasguy

It would be cheaper to go just buy a CDI. You would have to re-engineer the block and recast the block and head.

Besides 2 stroke diesels sucked, I remember the old Detroits. Heck I got smoked by a tired 8-71TI in a Hattares 53 a couple of weeks ago. Loud smokey old things. Why would anyone want such an annoying engine?

One of the boats I fish off of has a pair of 6-71's which are super loud and annoying. You fire them off at 4am and they cover half the parking lot in smoke. Not to mention you have to shout at cruise, loud SOB's! I think he should repower with a set of modern Cummins or Volvo's. The new computer controlled engines are better.

Because i can?

gota do something with this engine laying around here.. and who has done this conversion before? nobody. I think it will be fun and interesting and quite a story.

Now, my thoughts on the valvetrain.. Why not get rid of the cams alltogether and install electronic solenoids to actuate the valves? im sure they can be more than quick enough and there is a ton of things you can do with electronics, adjusting valve timing is just the start..

Uh oh.. look at this.. 80kn of pushing force... thats alot... http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=102700

junqueyardjim · #25 02-13-2008, 10:39 AM

Cervan, if you will let a pair of smart dolphins design it, it will probably run better and cost you a lot less money. Now did you know that a guy by the name of "Airship" Pennington designed a two cylinder petroleum fueled engine in Franklin, Indiana, as I recall before 1880. I wonder why they called him "Airship"

GREASY_BEAST · #26 02-13-2008, 01:45 PM

Cervan, if you are actually serious about making a powerful 616, heres what you should do:

1) keep it 4 stroke due to extreme costs of trying (and probably failing) to make it 2 stroke

2) take the engine apart and install piston oil squirters from a turbo 617 (yes it has been done)

3) take the head apart and install sodium cooled valves from a turbo 617

*) now you have an engine that is on par with a turbo 617 in terms of robustness and ability to take power mods

4) install an appropirately-sized VNT

5) Get an injector pump with 8mm or 10mm elements. 4 plunger M-Pump clones are available elsewhere in the world with bigger elements. Find one and buy it.

6) upgrade your injectors (265 nozzles at the least, 2 stage injectors are probably what you are really after though)

7) The only real sticky point is the cam. You may have to get a cam ground because turbo and non-turbo cams are different.

With these mods, you don't really have to do anything drastic to the engine, and you aren't really re-inventing the wheel anywhere, and therefore will probably cost you a predictable (albeit still fairly large) sum of money. The head and block mods have been done commercially (look up Force Motors in India).

EDIT: you also need one hell of an intercooler, and maybe water injection or some other method of keeping the EGTs down

Cervan · #27 02-13-2008, 01:52 PM

Quote:

Originally Posted by GREASY_BEAST

Cervan, if you are actually serious about making a powerful 616, heres what you should do:

1) keep it 4 stroke due to extreme costs of trying (and probably failing) to make it 2 stroke

2) take the engine apart and install piston oil squirters from a turbo 617 (yes it has been done)

3) take the head apart and install sodium cooled valves from a turbo 617

*) now you have an engine that is on par with a turbo 617 in terms of robustness and ability to take power mods

4) install an appropirately-sized VNT

5) Get an injector pump with 8mm or 10mm elements. 4 plunger M-Pump clones are available elsewhere in the world with bigger elements. Find one and buy it.

6) upgrade your injectors (265 nozzles at the least, 2 stage injectors are probably what you are really after though)

7) The only real sticky point is the cam. You may have to get a cam ground because turbo and non-turbo cams are different.

With these mods, you don't really have to do anything drastic to the engine, and you aren't really re-inventing the wheel anywhere, and therefore will probably cost you a predictable (albeit still fairly large) sum of money. The head and block mods have been done commercially (look up Force Motors in India).

EDIT: you also need one hell of an intercooler, and maybe water injection or some other method of keeping the EGTs down

hmm... from the sounds of this.. it may just be better to go buy a 300sd with a 603 in it.. then build that engine..

MB-Owner-in-ind · #28 02-13-2008, 02:06 PM

I never saw a 2 cycle engine with intake valves. I think the scavenging capability of an intake valve next to an exhaust valve would make this engine run poorly at best.

Hatterasguy · #29 02-13-2008, 02:11 PM

Quote:

Originally Posted by Cervan

hmm... from the sounds of this.. it may just be better to go buy a 300sd with a 603 in it.. then build that engine..

Well after all that work a 616 may put out almost as much power as a stock 603.

ZackaryMac · #30 02-13-2008, 09:00 PM

Quote:

Originally Posted by MB-Owner-in-ind

I never saw a 2 cycle engine with intake valves. I think the scavenging capability of an intake valve next to an exhaust valve would make this engine run poorly at best.

2 stroke gas engines don't have valves like you are probably thinking (reed, rotary, or the piston itself are the valves), however 2 stroke diesels all do, to the best of my knowledge. As mentioned before, the valves are all exhaust, as the air is brought into the cylinder through "holes", or ports, part way up the cylinder wall. If you've ever seen a chainsaw engine apart, you'd have a good idea what this is similar to.

2 stroke gas use oil in the gas or injected oil for crank/cylinder lube, 2 stroke diesels use engine oil like any other diesel.

2 stroke gas typically are naturally asperated (I have heard of race turbo'ed engines), 2 stroke diesel have to be force inducted (supercharged) to run.

Same name, similar concept, much different excecution.