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+--- Thread: Gas Powered 2 stroke OM617 (/showthread.php?tid=5313)
Gas Powered 2 stroke OM617 - jsl240z - 02-04-2014
Hi new member here, I often read the forums here but I have not joined until now. The reason I had to join was to share the amazing pictures I found. It appears to be a OM617 with a custom head converted to run as a gas powered 2 stroke. This is easily one of the coolest engines I have seen.
![[Image: DSC02937.jpg]](http://i298.photobucket.com/albums/mm268/punkrider99punkrider99/DSC02937.jpg)
![[Image: DSC02939.jpg]](http://i298.photobucket.com/albums/mm268/punkrider99punkrider99/DSC02939.jpg)
![[Image: DSC02938.jpg]](http://i298.photobucket.com/albums/mm268/punkrider99punkrider99/DSC02938.jpg)
RE: Gas Powered 2 stroke OM617 - Simpler=Better - 02-04-2014
That is incredible! Belt driven supercharger, crossflow billet head...if it's for sale buy it no matter what.
RE: Gas Powered 2 stroke OM617 - lgreeley83 - 02-04-2014
I want to hear it run :-)
RE: Gas Powered 2 stroke OM617 - MFSuper90 - 02-04-2014
Wow, that's incredibly interesting
RE: Gas Powered 2 stroke OM617 - raysorenson - 02-04-2014
How does is work without intake and exhaust ports in the cylinders?
RE: Gas Powered 2 stroke OM617 - Tmadia - 02-04-2014
Wonder why a 2 stroke needs a camshaft.
Looks to me like a custom made 4 valve per cylinder head with those 10 exhaust pipes.
RE: Gas Powered 2 stroke OM617 - Duncansport - 02-04-2014
(02-04-2014, 12:06 PM)raysorenson How does is work without intake and exhaust ports in the cylinders?
Note the intake and exhaust manifolds mount to the cylinder head...
RE: Gas Powered 2 stroke OM617 - CRD4x4 - 02-04-2014
(02-04-2014, 10:29 AM)lgreeley83 I want to hear it run :-)
If it really is a 2-stroke, it'd probably sound similar to this:
http://m.youtube.com/watch?v=EmnsXTMLzCE
RE: Gas Powered 2 stroke OM617 - Duncansport - 02-04-2014
(02-04-2014, 01:29 PM)Tmadia Wonder why a 2 stroke needs a camshaft.
Looks to me like a custom made 4 valve per cylinder head with those 10 exhaust pipes.
Im guessing here, but a long time ago Toyota made a two stroke engine that had the camshaft timing events happen every compression stroke. They did this by forced induction and very late intake timing as well as overlap. This helped scavenge the cylinder of exhaust. Then there would be a fuel delivery via a direct injector, piston goes down and both valves open, exhaust is forced out by incoming air, ect. Similar to a miller cycle engine.
RE: Gas Powered 2 stroke OM617 - lgreeley83 - 02-04-2014
Oh yeah and did they barrow that rusty engine block from Simple? another one from under the ocean.
(02-04-2014, 01:57 PM)CRD4x4 If it really is a 2-stroke, it'd probably sound similar to this:
http://m.youtube.com/watch?v=EmnsXTMLzCE
That is awesome. Is there a reason in theory as to why it looks like an octopus?
RE: Gas Powered 2 stroke OM617 - raysorenson - 02-04-2014
2 strokes that require a supercharger for scavenging use positive displacement superchargers. That's centrifugal.
RE: Gas Powered 2 stroke OM617 - ecFSE - 02-04-2014
http://www.youtube.com/watch?v=IRiGq-VYWUk
RE: Gas Powered 2 stroke OM617 - swampmonkey - 02-04-2014
there is a lot of talk and not much numbers...
still havent figured out completly how it works, it "injects air-fuel" mix at the same time it blows the exhausts out?
what about the air-fuel mixture you blow out the exhaust? and the exhausts that stay in?
different timing of valves in different rpms? seeing how hugh of difference exhaust port timing changes characteristics of a regular two-stroke.
i call bogus untill proven other
why not run it in a car? what about expansionchamber exhaust pipes instead of straight?
looks to me like it isnt exactly "well" made or i might be missing some point.
put it in a car, get me some HP numbers and get rid of the hideous quality+animations and i might be interested
RE: Gas Powered 2 stroke OM617 - jsl240z - 02-04-2014
Interesting responses, let me try clear up some things. First off the engine was made by legendary racer and engine builder Bruce Crower. The engine has a camshaft for the 2 exhaust valves per cylinder, there are no intake valves and it runs a positive displacement supercharger as the fuel/mix is forced in during compression of the cylinder.
RE: Gas Powered 2 stroke OM617 - Duncansport - 02-04-2014
Bruce did a lot of cool experimental engine work. Six stroke engine comes to mind,
Im sure there are no "HP numbers" for this engine as it was most likely a design study of some sort.
RE: Gas Powered 2 stroke OM617 - swampmonkey - 02-04-2014
(02-04-2014, 05:03 PM)jsl240z Interesting responses, let me try clear up some things. First off the engine was made by legendary racer and engine builder Bruce Crower. The engine has a camshaft for the 2 exhaust valves per cylinder, there are no intake valves and it runs a positive displacement supercharger as the fuel/mix is forced in during compression of the cylinder.
hmm, how does it force the air/fuel mix into the cylinder? throu what?
seeing there seems to be a carburator before the supercharger, and it going into the head, hard to imagine that beeing directly feed into the cylinder true an open port?
seeing the pictures presented in the video i could swear there was an intake valve, but those ideas perhaps are totaly different ways of solving the two-stroke but both on an om617?
it shure as hell is cool, been in the thoughts of building myself a 2 stroke 1liter or 2 liter engine myself, seeing that my dirtbike put out 50hp from 250cc, 200hp from one liter and 400hp from 2 liter would be cool as hell
untill one has to fill it up :/
RE: Gas Powered 2 stroke OM617 - willbhere4u - 02-04-2014
looks like a normal 4 stroke set up to me just 4 valves per cylinder and gas
RE: Gas Powered 2 stroke OM617 - sassparilla_kid - 02-04-2014
Ooohhhhhhhhhhhhh what the hell is this thing?
RE: Gas Powered 2 stroke OM617 - jsl240z - 02-04-2014
The engine does not need an intake valve because the piston rises to the point of covering the intake port. It seems to have many similarities with a detroit diesel 2 stroke.[/quote]
RE: Gas Powered 2 stroke OM617 - swampmonkey - 02-04-2014
(02-04-2014, 07:48 PM)jsl240z The engine does not need an intake valve because the piston rises to the point of covering the intake port. It seems to have many similarities with a detroit diesel 2 stroke.
okay, then it makes more sense, looking at the pictures, there seems to be no modifications to the block, but only the head is changed, but if they somehow has managed to get the inlet port to be covered by the piston it suddenly seems more ok
expansionchambers in the exhaust is nothing you have seen? seeing how different characteristics one gets just by altering the geometry on a regular two-stroke i was surprised to not see it on one of thse.
RE: Gas Powered 2 stroke OM617 - Eric78 - 02-05-2014
(02-04-2014, 12:06 PM)raysorenson How does is work without intake and exhaust ports in the cylinders?
It has a cam & valves, the cam is driven at the same speed as the crank, engines like this usually can't run without being under some amount of boost, this kind of mod is more commonly done to large motorcycle engines used for drag racing.
With the trouble gone to to make a custom head I'm surprised the builder didn't make it cross-flow too.
RE: Gas Powered 2 stroke OM617 - sassparilla_kid - 02-05-2014
It looks like its crossflow, as the blower is going into the side of the engine with the oil filter, while the other side looks like exhaust?
RE: Gas Powered 2 stroke OM617 - dude99 - 02-05-2014
lgreeley83 Is there a reason in theory as to why it looks like an octopus?
Yes, performance two stroke use tuned expansion chamber systems to improve performance. The swelled section of each pipe is calculated so that it creates a sound wave that bounces back up towards the engine. This wave pushes the fuel mixture that leaked into the exhaust system during the intake stoke back into the cylinder, sort of a supercharging effect.
Here's a moving diagram that illustrates the principle http://en.wikipedia.org/wiki/File:Arbeitsweise_Zweitakt.gif
The pipes are tuned so as they do this in a desired rpm range. This is one of the reasons why on a two stroke motorcycle with a tuned pipe you experience that sudden surge at a certain rpm. That surge is rebounding wave coinciding with the engine speed and pushing the fuel back in.
RE: Gas Powered 2 stroke OM617 - Eric78 - 02-05-2014
(02-05-2014, 12:35 AM)dude99 <quote=lgreeley83>Is there a reason in theory as to why it looks like an octopus?</quote>That isn't a functional expansion chamber, no convergent & divergent cones in that system, also expansion chambers usually don't work with mechanical exhaust valves, which is why 2 stroke diesels don't use expansion chambers.
Yes, performance two stroke use tuned expansion chamber systems to improve performance. The swelled section of each pipe is calculated so
RE: Gas Powered 2 stroke OM617 - dude99 - 02-05-2014
Quote:That isn't a functional expansion chamber, no convergent & divergent cones in that system, also expansion chambers usually don't work with mechanical exhaust valves, which is why 2 stroke diesels don't use expansion chambers.
I believe that he was referring to the video posted above, not the om617 in the first post. I answered regarding the piped in the video, which are expansion chamber pipes. I am aware that expansion chamber don't work with mechanical exhaust valves.
This video http://www.youtube.com/watch?v=EmnsXTMLzCE&app=desktop
RE: Gas Powered 2 stroke OM617 - Eric78 - 02-05-2014
(02-05-2014, 01:31 AM)dude99Quote:That isn't a functional expansion chamber, no convergent & divergent cones in that system, also expansion chambers usually don't work with mechanical exhaust valves, which is why 2 stroke diesels don't use expansion chambers.
I believe that he was referring to the video posted above, not the om617 in the first post. I answered regarding the piped in the video, which are expansion chamber pipes. I am aware that expansion chamber don't work with mechanical exhaust valves.
This video http://www.youtube.com/watch?v=EmnsXTMLzCE&app=desktop
Oops, my mistake.
In the video looks like two v4 outboard motors coupled together, or did they actually make V8 outboards?
RE: Gas Powered 2 stroke OM617 - jsl240z - 02-05-2014
In the video looks like two v4 outboard motors coupled together, or did they actually make V8 outboards?
[/quote]
Yes Evinrude made a 2 stroke v8 outboard.
RE: Gas Powered 2 stroke OM617 - raysorenson - 02-05-2014
(02-04-2014, 05:03 PM)jsl240z Interesting responses, let me try clear up some things. First off the engine was made by legendary racer and engine builder Bruce Crower. The engine has a camshaft for the 2 exhaust valves per cylinder, there are no intake valves and it runs a positive displacement supercharger as the fuel/mix is forced in during compression of the cylinder.
To be clear, I'm talking about this engine:
What I don't understand here is how the pictured supercharger is positive displacement. If someone could clarify for me how, what appears to be a centrifugal supercharger, is a positive displacement supercharger I would be appreciative.
RE: Gas Powered 2 stroke OM617 - MFSuper90 - 02-05-2014
Anybody else see those sparkplug wires hanging down the side of the procharger?
RE: Gas Powered 2 stroke OM617 - Simpler=Better - 02-05-2014
It's a gas conversion, I bet there's some kind of distributor where the IP should be.
The air intake could be a flapper valve-when then piston is drawing down, or the boost exceeds the exhaust pressure fresh air comes into the cylinder. When the cylinder pressure is higher than the intake (compression/firing) the flapper would be forced closed. The cam now runs all 10 valves as exhaust valves.
RE: Gas Powered 2 stroke OM617 - winmutt - 02-05-2014
I want more pics and video of it turning by hand!
RE: Gas Powered 2 stroke OM617 - MFSuper90 - 02-05-2014
A procharger like pictured isn't a positive displacement supercharger, so how could it work like a 2stroke Detroit?
RE: Gas Powered 2 stroke OM617 - Simpler=Better - 02-05-2014
(02-05-2014, 12:24 PM)MFSuper90 A procharger like pictured isn't a positive displacement supercharger, so how could it work like a 2stroke Detroit?
I don't think it needs to. Gas will fire with practically no compression (my bike fires with 95psi) so you would just need to start it "normally" maybe run the choke a bit.
The charger is there for power probably. Once you're up and spinning at 5k, it's going to blow a lot more fuel in there than just vacuum through the manifold.
RE: Gas Powered 2 stroke OM617 - willbhere4u - 02-05-2014
I'm still not convinced its actually a 2 stroke. It may very well be a 4stroke with a blower
Gas 2 strokes often use a reed valves for the intake. And supercharging is not necessary with a gasoline 2 stroke engine but can be done anyways
RE: Gas Powered 2 stroke OM617 - yankneck696 - 02-05-2014
With the cog ratios, that procharger is spinning pretty darn fast. I would think it's definitely giving airflow at cranking speed. I would also think with that overspeed, it would be pretty hot, too.
Ed
RE: Gas Powered 2 stroke OM617 - MFSuper90 - 02-05-2014
(02-05-2014, 12:41 PM)Simpler=Better(02-05-2014, 12:24 PM)MFSuper90 A procharger like pictured isn't a positive displacement supercharger, so how could it work like a 2stroke Detroit?
I don't think it needs to. Gas will fire with practically no compression (my bike fires with 95psi) so you would just need to start it "normally" maybe run the choke a bit.
The charger is there for power probably. Once you're up and spinning at 5k, it's going to blow a lot more fuel in there than just vacuum through the manifold.
Very true, my brain is still in diesel mode
RE: Gas Powered 2 stroke OM617 - jsl240z - 02-06-2014
It definitely looks like the blower is geared up to make pressure at all times. I assume this is necessary because the air/fuel mix is not being drawn in, it is being forced in during compression.
RE: Gas Powered 2 stroke OM617 - Eric78 - 02-06-2014
(02-04-2014, 05:03 PM)jsl240z The engine has a camshaft for the 2 exhaust valves per cylinder, there are no intake valves and it runs a positive displacement supercharger as the fuel/mix is forced in during compression of the cylinder.Are you sure there's no intake valves? The intake does run into the head, even with forced induction 2 stroke engines still need a means of covering/closing the intake ports.
RE: Gas Powered 2 stroke OM617 - Tito - 02-06-2014
That's indeed true. Normal small 2-stroke engines use crankcase pressure to draw en push mixture from carb to cylinder.
RE: Gas Powered 2 stroke OM617 - Eric78 - 02-06-2014
(02-06-2014, 04:09 AM)Tito That's indeed true. Normal small 2-stroke engines use crankcase pressure to draw en push mixture from carb to cylinder.
Not only that, they also have either a rotary valve, a reed valve or are piston ported.
If that engine is only using the pistons for intake timing it means the crowns of the pistons have to actually touch the head which would be very destructive pretty quickly.
RE: Gas Powered 2 stroke OM617 - Simpler=Better - 02-06-2014
We need more pics!!
The valve cover looks like it's made of lexan-can you get a picture down through the top?
RE: Gas Powered 2 stroke OM617 - jsl240z - 02-06-2014
Quote:We need more pics!!
The valve cover looks like it's made of lexan-can you get a picture down through the top?
I did not take the pictures I just found them.
Quote:If that engine is only using the pistons for intake timing it means the crowns of the pistons have to actually touch the head which would be very destructive pretty quickly.
Because I do not know anything about the engine other than what I can infer from the pictures, I am only speculating on it's operation. What I do observe is that the head is a great deal taller than the stock one and the combustion chamber and piston design is unknown. If the pistons have crowns is also an unknown. I know a little about engine design and If I could make my own head I would not use crowned/domed pistons, just my thoughts.
RE: Gas Powered 2 stroke OM617 - willbhere4u - 02-07-2014
It only looks tall the cylinder head is only the bottom half. The top half is a fancy valve cover possibly holding the cam
Can you post a link as to where you found these photos?
RE: Gas Powered 2 stroke OM617 - CRD4x4 - 02-07-2014
Here's a mention of the 2-stroke mercedes engine, presumably the same as pictured above.
http://www.jalopyjournal.com/forum/showthread.php?t=369048