# opposed engines



## tim1972 (Jun 19, 2012)

I have seen on you tube where some people bolted to engines together by the heads making one cylinder. A few I have notice are two stroke engines.So now for the dum question Is this the only way you can make this type of engine is with two stroke?


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## ChuckH (Apr 23, 2012)

tim1972 said:


> I have seen on you tube where some people bolted to engines together by the heads making one cylinder. A few I have notice are two stroke engines.So now for the dum question Is this the only way you can make this type of engine is with two stroke?


Do you have a link? I have to see this. I suspect they used 2 strokes because the lubrication is in the fuel so no oil sump.


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## Hoodoo Valley (Nov 14, 2006)

Also, what would be the advantages I wonder?


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## Mickey (Aug 14, 2010)

Since you said they were bolted together at the head, one much give thought to the valves. How can the valves work if the engines are facing one another. Unless the engines were a flat head design there wouldn't be any valves. Also, since he pistons normally go up to the top of the cly, where is the combustion chamber? You can't compress the gases into zero space.

Also don't see how this could work with a 2 cycle unless the pistons were flat which many times isn't the case. And we still have the lack of a combustion chamber.

Not mentioned but possible was the insertion of a spacer between the tops of the cyl that could function as the combustion chamber.


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## Rusty (Jun 15, 2011)

Please post a link to this video so we can see what the heck you're talking about. bolting engines together at the head makes no sense to me.Why,and What for?


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## tim1972 (Jun 19, 2012)

*youtube*

youtube search key words opposed 2 crankshaft engine running


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## stickerpicker (Sep 16, 2003)

The natural gas turbo dual crank opposed piston I've retired from operating and maintaining was a 2 cycle. 4 cycle would be somewhat difficult I'd think.

I've heard a very similar engine, probably in diesel, can be viewed in Muskogee,OK on the submarine USS Batfish.

This Fairbanks in the link is the exact engine except ours was the 6 cyl. version. All boiler plate construction frame and a bunch of horses for such a small package. 

http://www.tugboatenthusiastsociety.org/Pages/tugmach-diesel-modern-FM.htm


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## Hoodoo Valley (Nov 14, 2006)

stickerpicker said:


> The natural gas turbo dual crank opposed piston I've retired from operating and maintaining was a 2 cycle. 4 cycle would be somewhat difficult I'd think.
> 
> I've heard a very similar engine, probably in diesel, can be viewed in Muskogee,OK on the submarine USS Batfish.
> 
> ...


Certainly some great reading. Thanks for the link Sticker!


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## stickerpicker (Sep 16, 2003)

tractor beam said:


> Also, what would be the advantages I wonder?


I'm suspecting double the length of stroke since length of stroke is a one determining factor of horse power.

Disadvantage - that engine is about 8 ft. tall.

PLAN / 33000

P = brake mean effective pressure
L = length of stroke
A = area of cylinder in sq. in.
N = no. of power strokes / min. 

I hope I got that right. It's been awhile.

I'll not deviate from the OP's question more after mentioning one more thing about the Fairbanks engine in the link.

If you look closely at the end view cross section picture in the link you can detect there is a slight difference in the timing of the upper and lower crank shafts. i.e. while the connecting rod on the upper shaft is vertical the rod on the lower shaft isn't by just a few degrees and the purpose was for exhaust purging.


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## Hoodoo Valley (Nov 14, 2006)

But could you imagine the logistical nightmare of bringing those two cranks together for one power source, let alone rebuilding the engine when the time came? Still, that is one cool concept no doubt!


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## Mickey (Aug 14, 2010)

With link to youtube I'm getting a different picture. This is not merely the bolting two engines together at the head. The B&S example did address the issue I brought up about missing combustion chamber. There is a spacer between the two engines and from description, the cyls are not in-line. In my initial post I forgot to bring up the fact if the engines were merely bolted together, there'd be no provision for the spark plug.

Nothing real special about opposed twin with two cranks. Just needs to address valve issue and spark.

Here is a pic of such an engine but it was designed from scratch and addressed all the issues. Pic taken at the Portland Or. GEARS model engine show a couple yrs back.


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## Rusty (Jun 15, 2011)

I still don't see the reasoning here,BMW and even Harley Davidson built hrizontal twins using a single crank, the only use I can think of for this set up would be Nautical, in applications where you would have twin screws(propellers for you land lubbers) also,are the rotation of the cranks the same?


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## Larry in OK (Jul 22, 2010)

stickerpicker said:


> The natural gas turbo dual crank opposed piston I've retired from operating and maintaining was a 2 cycle. 4 cycle would be somewhat difficult I'd think.
> 
> *I've heard a very similar engine, probably in diesel, can be viewed in Muskogee,OK on the submarine USS Batfish.*
> 
> ...


Opposed piston engines are pretty common in diesel engines used as emergency generators on US submarines, at least they were 20 years ago when I was still making my living riding them.

Also if you're ever in the area the USS Batfish museum in Muskogee is very worth the visit.


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## tim1972 (Jun 19, 2012)

Thank you all for your replies. Also I found my answer Larry in OK, your link and explanation of where these where used. I would never guess that type of engine would be used.


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