White Is Wonderful!(post Omc Pics Here)

[gmcgruther]

U wanna know what a stock block looks like? 6 runners going into a "tuner" covered by an exhaust chest There were different blocks over the yrs some work better than others depending on what your looking to do and how hard you wanna turn them.

I have to ask this because it seems you don't know what the inside of the exhaust cavity of a OMC looks like? For one, each cylinder dumps directly into its own exhaust pipe should I say header pipe, on that particalure bank (which there is three), then dumps in a single opening for that side(Collector), same go's for the other side. then it go's in to a tuner(Collector extension). The two different blocks are open deck and closed deck. One has bigger ports then the other. I did find this out by making a few phone calls. All I needed was the resource's to get this going and I found them. Thank you guy's. It's been a bumpy road from the start but life is not easy. If I came off sounding arrogant, I'm sorry, I miss place words or type the wrong words and sound that away. In the futhure if I do the same please ask me to reword it to not to sound arrogant. I don't know everything but I do have the resource's to have things done and I need some guidence at times.

[2.5_stoker]

[BarryStrawn]

Not to sound cocky but don't the 3 into one dump directly in one cavity? If not, I stand corrected then( A simple header.) The Mercury does not have the same system, remove any exhaust plate on a Mercury and see all three dump at once( not individaully like a omc) then into a tuner then dumps in to single area. Mercury is more of a simple vehicle exhaust manifold not a header design.

Do you need an explanation of how 120 degree exhaust tuning works on a three cylinder two stroke?

[gmcgruther]

Do you need an explanation of how 120 degree exhaust tuning works on a three cylinder two stroke?

Please do, But remember we are speaking of a 2 stroke v-6. Remind you I do know what a OMC exhaust looks like in the exhaust cavity! Thanks to someone very special. No names mentioned but he did Ray Leach's engine! Ok.

[gfinch]

Had a lot help from a lot of good people! The latest part of the project is getting close to completed. We managed to make a trim system that is much faster. Reduced the time from fully tucked under to neutral, 2.5-3 seconds to about 1 second. The boat is more manageable and quicker now on take off.

Beginning of last year
http://youtu.be/ywOB6z2_Qc4
Third and last day of tuning at Havazoo, Az.
Last year at Lake Shasta, Ca.
http://youtu.be/RkIaIr5nTr4
WAR10 May 2010 Trim was to slow to tuck under and take off, boat just laid on it's side until trim caught up.
Last weekend after fixing two problems.
http://youtu.be/49-FxypAKQE
New trim system.
Same
http://youtu.be/xuV5dBiTWdI
Single ram on 24 volts.

Now I have to slow down the 12 volt system because it's too fast to fine tune the trim. Have a coil of 10 guage wire probably 30' long with a tap at probably 20'. Drops the voltage = slows the trim pump motor.
I have ordered a speed controller(Pulse Modulation) so I can fine tune it and not burn up the trim motor.

A special thanks to Dave, Andy and Stan and numerous others that have helped on this project.

Gary

[BarryStrawn]

Please do, But remember we are speaking of a 2 stroke v-6. Remind you I do know what a OMC exhaust looks like in the exhaust cavity! Thanks to someone very special. No names mentioned but he did Ray Leach's engine! Ok.

For exhaust tuning purposes, most folks think of a V6 as two three cylinders joined with a common crankshaft. Any interaction down in the midscetion where both banks dump has no effect. How the three cylinders in each bank interact is the important part.

This is from an old SAE paper written by two OMC engineers that explains the basics.

Fig 6 shows a port timing diagram for a three cylinder engine firing at 120 degree intervals. The diagram shows that just prior to the closing of the exhaust port of one cylinder, the exhaust port opens in a succeeding cylinder creating a positive pressure pulse in the exhaust manifold. Fig 7 shows the sequence of these positive pressure pulses.

[gmcgruther]

For exhaust tuning purposes, most folks think of a V6 as two three cylinders joined with a common crankshaft. Any interaction down in the midscetion where both banks dump has no effect. How the three cylinders in each bank interact is the important part.

This is from an old SAE paper written by two OMC engineers that explains the basics.

Fig 6 shows a port timing diagram for a three cylinder engine firing at 120 degree intervals. The diagram shows that just prior to the closing of the exhaust port of one cylinder, the exhaust port opens in a succeeding cylinder creating a positive pressure pulse in the exhaust manifold. Fig 7 shows the sequence of these positive pressure pulses.

Thanks for the information but The exhaust does'nt look anywhere near like that one picture, it has one pipe per exhaust leading to one on one side and same goes for the other side, the top exhaust goes in a casted aluminum pipe going down, the center goes in casted aluminum pipe going straight foward and the Bottom exhaust goes in a casted aluminum pipe going up which they all join in the center of the exhaust cavity and same goes for the other side, then they have a down spout going down to a tuner which is located in the midsection below the power head. Beside's that the engine does'nt fire all three on one side then goe's to the other side. it's two and one the other side does the samething. so it's firing two on one side and one on the otherside then vise versa. Always having a pulse signal.

[moomba]

75HP Stinger looking for a new home

[BarryStrawn]

Good luck with your project.

[baja200merk]

I have to ask this because it seems you don't know what the inside of the exhaust cavity of a OMC looks like?

I dont know what it looks like? Even after watching monty's process on a sister motor to one of leach's pipe motors?

The runners and chests changed quite a bit over the years, the smallest displacement v6 loopers have the best flowing exhaust chest.

[BarryStrawn]

Thanks for the information but The exhaust does'nt look anywhere near like that one picture, it has one pipe per exhaust leading to one on one side and same goes for the other side, the top exhaust goes in a casted aluminum pipe going down, the center goes in casted aluminum pipe going straight foward and the Bottom exhaust goes in a casted aluminum pipe going up which they all join in the center of the exhaust cavity and same goes for the other side, then they have a down spout going down to a tuner which is located in the midsection below the power head. Beside's that the engine does'nt fire all three on one side then goe's to the other side. it's two and one the other side does the samething. so it's firing two on one side and one on the otherside then vise versa. Always having a pulse signal.

I think I am going to regret posting this, but the firing order is 1-2-3-4-5-6. Think about it for a while.

[baja200merk]

then they have a down spout going down to a tuner which is located in the midsection below the power head. .

its not a 2.5 merc

[6Killer]

Barry: Thanks for posting that pic. It is truly amazing how so few people understand what is going on there. It is the heart of of the exceptional performance a 6 cylinder 2 stroke has to offer, or a 3 cylinder for that matter.

gmac, you say it doesnt look like an OMC and you are right.

BUT, you need to study it very carefully, the shape might be slightly different but they do the same thing with the same benefical effect on performance.

[gmcgruther]

I dont know what it looks like? Even after watching monty's process on a sister motor to one of leach's pipe motors?

The runners and chests changed quite a bit over the years, the smallest displacement v6 loopers have the best flowing exhaust chest.

Ok, Let me explain something to you, I six pictures of leachs engine as it was first cut then rewelded, sent by monty him self after I talked to him after a hr and a half on my project i want to do, oh by the way ford V-8 1234 ON ONE SIDE THEN 5678 ON THE OTHER SIDE DOES THAT MEAN ITS FIRING THE SAME WAY. THE FIRING ORDER MIGHT BE 123456 BUT I bet the number one cylinder is the opposite side of number two. Dave Bush and I talked for a hr and a half today, trust me,I have been schooled on way the exhaust works and why it will be difficult to get any large amount of power unless we use stinger pipes then we can see some good power and if we can figure out the exhaust like yamaha did on the 2 strokes we could be lookin at 1000+hp and room to play. yes Dave and I talked long and hard about every aspect of this project and the no go's and possiblities. Both Monty and Dave are full of knowledge and I got to pick at it and get information on where to go to get more. Don't get me wrong I'm not a know it all but when I get my information from this guy's, I think there alittle more well tuned then you and I. Yes there is reverse pulse's but not do to what you think, Thats why a stinger pipe will make thee best supercharger effect on the exhaust side. Just call Dave and get schooled and same goes with Monty, call him to and they'll have a very close if not the same thing to say.

[gmcgruther]

Barry: Thanks for posting that pic. It is truly amazing how so few people understand what is going on there. It is the heart of of the exceptional performance a 6 cylinder 2 stroke has to offer, or a 3 cylinder for that matter.

gmac, you say it doesnt look like an OMC and you are right.

BUT, you need to study it very carefully, the shape might be slightly different but they do the same thing with the same benefical effect on performance.

Maybe you should look at Yamaha's exhaust on there two strokes compare that to OMC exhaust! As Dave said to me, "If we can get the same exhaust as Yamaha has, the 3.3L would of been 600 hp bone stock." Yes thats what Dave said. now think about that. There making 300 to 385 hp N/A on three cylinders now add 3 more. There turbo two stroke has hit 400 already and it's not on kill yet and it's a three cylinder. So yes two strokes are a wonderful thing if OMC AND MERC would do there homework they could be extremely fast too.