Making a small fortune from a 2 stroke V8 1

[motorsportsdesign]

Here is my plan....Start with a large fortune, then make a large V-8 2 stroke for sportsman dragster racing.

The basic scheme is a supercharged piston port design with 4.840 bore spacing so I can use big block Chevrolet crank and rods.

The foggy areas for me at this point are port design, since the 2 stroke design software that I have looked into so far is not a good fit for bores in the range of 4.0".

I will also need to find a source for a piston with a ring on the bottom, I wonder, can a ring on the bottom piston be forged? It seems that it would be a big undercut.

Last thought is if the engine would require expansion chambers to make good power as they might be rather bulky I will have to model that to see once I have the approximate dimensions.

Any thoughts would be appriciated.


Jonathan T. Schmidt

http://www.motorsportsdesign.com

 

[Grue]

Maybe you'd like to start with a model V8 plans and castings available on my site.

We have managed to get 3.2HP at 5000RPM.

Specification 1/2" bore, 3/4" stroke approx 1/6 scale. Length 5 5/8", width 6 5/8", height 7/78" over air cleaner, 6 1/8" under bonnet. Capacity 19.31cc - 1.178cu" Idles around 800RPM.

Glenn.

http://www.metalbashatorium.com

 

[Snork]

I suspect with enough money you could get pistons made with rings on the bottom, but even with a piston ported design I'm not sure why you need this. Piston ported 2 strokes typically don't have a ring there.

As to expansion chambers - YES you will need them to make the engine run well. I have personally witnessed a person who took a well tuned 500 cc 2 stroke at about 105 hp, and turned it into a helpless pile of junk that could barely move the vehicle by simply removing the tuned pipe and replacing it with 4 stroke type exhaust. A good place to start is Blair - Design and Simulation of Two Stroke Engines - available from SAE. Be aware that good pipe design is only about a quarter science - the rest is sweat, hard work, and most importantly, innate ability granted by the Gods for the promise of the soul of your first born.

Good luck.

 

[76GMC1500]

500cc Grand Prix bikes are pushing near 200hp out of the 2-stroke engines. When you say you are going to use a block of similar size to a BBC, I see a few potential problems. You're going to have huge cylinders, 800-900cc's each. This means you will have scavinging difficulties, especially at higher rpms. In order to overcome the scavenging difficulties, you will need to have a very long stroke to give the cylinder plenty of time to scavenge. In order to accomodate the long stroke, you would have to use a very tall deck block which is heavy, and the long stroke of the crankshaft will limit how many RPM's you can turn. For naturally aspirated applications, you would have to seal a chamber underneath each cylinder in order to get the compression and vacuum needed to draw fuel into the engine and force it into the cylinders. This would add weight and the crankshaft seals would create a lot of drag. And, finally, for forced induction applications that do not move air through the crank case prior to it entering the cylinder will have to have a piston skirt longer than the stroke with a 2nd set of rings in order to keep the scavenge ports from becoming uncovered and supercharging the crankcase.

I hate to be so negative, but if you were to find a way around these problems, you could pull in a small fortune as you said, but not through racing. Instead, I'd think companies like Detroit Diesel would be very interested.

 

[i278]

motorsportsdesign,

Well, if you've already got the large fortune, why don't you just bolt together two of these V-4s:

http://www.deltahawkengines.com/drawin00.htm

It's diesel, of course, but the rest is close.

Regards

 

[patprimmer]

I thought Detroit Diesel made a large number of 2 stroke diesels in various capacities from 4 cyl to 14 cyl "V" configuration.

Also Johnson/Evinrude made a V8 2 stroke outboard motor some years ago. It might be down on capacity for your plans, but might be an easy starting point to prove or disprove some ideas.

Regards
pat

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[76GMC1500]

Mercury makes a 2 stroke gas engine that is good for some 350hp, but it is a realativly low displacement engine, not like the one described earlier. Formula 1 boats use 2 stroke engines, possibly v8's also.

There are plenty of large displacement 2-stroke diesels, but they are very limited on how fast they can turn. Almost all 2-stroke diesels are forced induction of some sort and run RPM ranges from 100-2100, none of which will do you much good for racing. The fact is that 2-strokes lose a great deal of efficience the faster they run.

 

[motorsportsdesign]

Thanks all for the input,

I am planning to avoid the crankcase pumping style in favor of the roots blower scavenging. I have ssen many diesels with blowers but with valves in the head.

Thanks for the reminder about the Deltahawk engine, I had not looked at it for some time!

Best Regards



Jonathan T. Schmidt

http://www.motorsportsdesign.com

 

[Warpspeed]

I like Pat Primmers idea. Find an old GM 4-71 two stroke diesel. Replace the diesel fuel injector with a spark plug, and fit some EFI fuel injectors into the intake plenum around the cylinder bores somehow.

You are going to have to lower the compression a bit, but otherwise it should run o/k. A four cylinder distributor working at crankshaft speed might do the trick as well for both fuel and spark timing.

With a blower scavenged two stroke, you do not need to have the fancy pressure wave exhaust, with the expansion chambers and the very limited powerband it gives.

You could even two stage it with a turbo, just as they do on larger diesel trucks these days. It might actually breathe pretty well, especially if it has four exhaust valves per cylinder, and you overdrive the blower a bit.

It is going to be a pretty heavy engine though. I wonder if you could get an aluminium block cast? Hehe.

 

[motorsportsdesign]

Warpspeed,

Thanks for the suggestion, casting blocks is not a big effort for me. I have made some very difficult tunnel ram intakes already.

I was planning to have piston port exhaust no valves in the head for simplicity. I am thinking that I will make billet heads like jet skis have.



Jonathan T. Schmidt

http://www.motorsportsdesign.com

 

[Warpspeed]

Valves in the head are going to give you the advantage of being able to alter exhaust timing quite independently of piston position. I think this would be a very great advantage for an experimental engine.

Another advantage is the piston temperature will be more even, if all the exhaust goes out through the cylinder head. Remember exhaust gas temperature is going to be far higher with gasoline, and a two stroke gasoline engine at that.

I think a standard Detroit Diesel might be a good starting point, mess around with it, then when you know a lot more, a custom block would give you an excellent opportunity to do some pretty amazing things.

 

[motorsportsdesign]

I really prefer to have a valvless head, my goal is to make the engine as simple as possible, no cams pushrods valves etc.

These engine will likely be run an alcohal, I'm not sure what that will be like in a 2 stroke.

On the four stroke engines the heads are solid as no cooling is needed.

Jonathan T. Schmidt

http://www.motorsportsdesign.com

 

[enginesrus]

Scott Mc,
The reason you want to have a ring at the bottom, is to keep the pressure from the intake ports from pressurizing the crankcase. Since at TDC the upper ring pack is above the intake ports. And since he is talking about a high positive pressure at the intake ports all the time. Unlike the naturally aspirated piston ported (as you say) design, which only has atmospheric or less at the inlet.

Using a Detroit diesel is a great idea.

 

[dwedel]

Cooper-Besmer and Ajax have 2-stk engines. They only turn 300 RPM and have significantly larger displacement than a 500 cc moto-GP engine. They maybe have a little more wieght than you want. However the priciples of operation may help you out. I think Ingersol-Rand makes a large gas compressor that is a 2-stk as well.

I was one of the people in college that thought 2-stks were only used in small, high rpm racing vehicles and outboard boats.

If you happen to win the lottery, I can think of a few other projects to help you spend the money!

 

[r4360]

ever thought about using the coates spherical valve type head. go to the coates web site this could solve your problem

 

[malbeare]

"motorsportsdesign (Automotive) Jan 29, 2004
I really prefer to have a valvless head, my goal is to make the engine as simple as possible, no cams pushrods valves etc.

These engine will likely be run an alcohal, I'm not sure what that will be like in a 2 stroke.

On the four stroke engines the heads are solid as no cooling is needed.
Jonathan T. Schmidt"
How about a head with an opposed piston and twostroke style porting and air assisted injection that can deliver alcohol fuel and nitros through the injector nozzle.

http://www.jack-brabham-engines.com/

Malbeare


A tidy mind not intelligent as it ignors the random opportunities of total chaos. Thats my excuse anyway
Malbeare

 

[motorsportsdesign]

"ever thought about using the coates spherical valve type head. go to the coates web site this could solve your problem"

The Coates head will only solve problems for those that want more problems. In my opinion there is no commercial future for any engine that has components that have a shperical surface for sealing. The machining is too costly and the wear and rebuild situation would be impractical.

Jonathan T. Schmidt

http://www.schmidtmotorworks.com

 

[motorsportsdesign]

Malbeare,

I took another look at your head, each time I look a little longer. I must tell you, I think you would be better served by a different name the six-stroke for marketing. Every time I hear it I think of some crazy cycle that has the piston making useless motion to air-out the cylinder.

How would you layout the head in a V12? The angle drive sounds too complicated, have you thought of any other schemes for cylinder rows of more than two cylinders?

I will give your design some more thought.

BTW, everytime I download the detailed animation from your site it is corrupt.

Jonathan T. Schmidt

http://www.schmidtmotorworks.com

 

[malbeare]

Jonathan T. Schmidt"

I have spoken to my webmaster about the corrupt file.
Our engine concept is a fourstroke principle. I named it a sixstroke as the upper piston completes two strokes while the main piston completes four strokes 4+2=6.The upper piston is a valving piston that returns some power to the main crank.The disks and or reeds augment the valving process but are not subject to cylinder pressures as the upper piston takes this.

what kind of V 12 are you looking at bore stroke capacity?
regards Malcolm Beare

http://www.jack-brabham-engines.com/

A tidy mind not intelligent as it ignors the random opportunities of total chaos. Thats my excuse anyway
Malbeare

 

[motorsportsdesign]

I understand the concept of your cycle, I just think it deserves a more appealing name. Sorry I can't think of one at the moment. I think something that emphasises the elimination of the poppet valves or follow Otto and Brayton and call it the Beare Cycle.

I have been considering making a 5.0 bore spacing V-12 with proportions most similar to current after marker Big Block Chevrolets used in Sportsman level drag racing about 1.2 HP/CUIN.
Every time I get ready to go for it and start writing checks I get nervous and start thinking about things like 2-stroke V8s that might be less costly.

At the moment I am prototyping a carburetor and also doing some experiments with lost foam casting from machined styrofoam. Actually at this point, I am less concerned about the casting than accurate machining of the foam.

Jonathan T. Schmidt

http://www.schmidtmotorworks.com