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Thread: Crescent 500 specs

  1. #11
    Team Member seacow's Avatar
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    More about Crescent from dicko'dea.com
    The Crescent Engines Story:

    In 1964, I was invited to participate in the World 500cc Hydroplane Championship in Stockholm, Sweden. I was invited by a friend to drive a Crescent powered Hydroplane. The only stipulation being that I had to bring my own boat and propellers. Sid-Craft built an 11 Ft. hydroplane and shipped it to Sweden before the May 30, 1964 race.

    I arrived about a week before the race and we did some testing on a small lake outside of Uppsala, Sweden. After I finished testing and feeling I had the boat going quite well, I was asked by the people of the Crescent company to let a German driver, Walter Vicer take a test run in the boat. He was used to driving a lay down hydroplane instead of a kneel down hydroplane, he was not familiar with the handling. On the 2nd or 3rd lap around the lake, he lost control of the boat and crashed into some large rocks at the end of the lake. He was quite severely injured. After looking over the damage, I felt the boat was beyond repair.

    The crescent people contacted a cabinet maker in Stockholm, Sweden, and in record time he was able to repair the boat and I was able to compete in the championship race. After all the excitement, I finished 2nd in the World 500cc Championship. During talks before my return to the US, it was decided that I would be the North American distributer for Crescent Racing Engines.

    The first alky engines arrived in the fall of 1964 and by 1965 the C-stock engines had started to arrive. The Super C-class was formed in APBA and competition began. After about 25 of the C-stock engines had arrived, I was advised by the factory they would no longer supply lower units or drive-shaft housings. They were kind enough to supply me the patterns and we started production of these items in the US. Approximately 25 drive shaft housings were built, 50 lower units, and we used Mercury clamp brackets to finish things off. All told, close to 50 C-stock engines were sold before Powerhead Productions had ceased and about 25 of the alky engines had been delivered in the US. The factory finally decided it was not profitable to manufacture anymore powerheads and we discontinued selling the engine.


    One mystery that should be cleared up; is that the only difference between C-stock and C-alky engine was that C-alky engine had higher compression and used 3 large O’Dea built alky carburetors.


    Today crescent engines have become quite collectible. A small group of Crescent owners in Sweden, still race the engines today with some small parts being made by vendors in Europe.

  2. #12
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    Default crescent power numbers

    Quote Originally Posted by seacow View Post
    More about Crescent from dicko'dea.com
    The Crescent Engines Story:

    In 1964, I was invited to participate in the World 500cc Hydroplane Championship in Stockholm, Sweden. I was invited by a friend to drive a Crescent powered Hydroplane. The only stipulation being that I had to bring my own boat and propellers. Sid-Craft built an 11 Ft. hydroplane and shipped it to Sweden before the May 30, 1964 race.

    I arrived about a week before the race and we did some testing on a small lake outside of Uppsala, Sweden. After I finished testing and feeling I had the boat going quite well, I was asked by the people of the Crescent company to let a German driver, Walter Vicer take a test run in the boat. He was used to driving a lay down hydroplane instead of a kneel down hydroplane, he was not familiar with the handling. On the 2nd or 3rd lap around the lake, he lost control of the boat and crashed into some large rocks at the end of the lake. He was quite severely injured. After looking over the damage, I felt the boat was beyond repair.

    The crescent people contacted a cabinet maker in Stockholm, Sweden, and in record time he was able to repair the boat and I was able to compete in the championship race. After all the excitement, I finished 2nd in the World 500cc Championship. During talks before my return to the US, it was decided that I would be the North American distributer for Crescent Racing Engines.

    The first alky engines arrived in the fall of 1964 and by 1965 the C-stock engines had started to arrive. The Super C-class was formed in APBA and competition began. After about 25 of the C-stock engines had arrived, I was advised by the factory they would no longer supply lower units or drive-shaft housings. They were kind enough to supply me the patterns and we started production of these items in the US. Approximately 25 drive shaft housings were built, 50 lower units, and we used Mercury clamp brackets to finish things off. All told, close to 50 C-stock engines were sold before Powerhead Productions had ceased and about 25 of the alky engines had been delivered in the US. The factory finally decided it was not profitable to manufacture anymore powerheads and we discontinued selling the engine.


    One mystery that should be cleared up; is that the only difference between C-stock and C-alky engine was that C-alky engine had higher compression and used 3 large O’Dea built alky carburetors.


    Today crescent engines have become quite collectible. A small group of Crescent owners in Sweden, still race the engines today with some small parts being made by vendors in Europe.
    I always wondered, how much horsepower these engines made in competitive-stock set up. I read somewhere that they came with a interchangeable tuned pipe in the exhaust. One was for short coarse and one for long coarse. Also, what level of RPM could these engines handle? I don't own one, but in case one day I come across one I sure would like to know more about it. These are interesting engines.

  3. #13
    Team Member seacow's Avatar
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    Further clarification. I asked Dick O'Dea if the Crescent was derived from the Saab motor. Here is the reply, although this still does not tell me if the motor is derived from a Saab design.

    "The Crescent was built by Monarch Crescent, they also built bicycles and mopeds.
    some of the same engineers may have been consulted. Most of the powerhead main components were made in Germany. M.C. was later purchased by Volvo Penta.
    -Dick O'Dea"

  4. #14
    BRF Team Europe Member Per's Avatar
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    From an article in "Nymans Vänner"

    Gösta Stillerud, Thure Åkerfldt and Carl-Erik Zander was in the original group that developed the engine, they worked for Nymans Verkstäder (the company that built the Crescent engines)

    The engine delivered 58hp (CS version) and 80hp (in C version) on methanol. At the time the Swedish speed record for C class was 92mph, of course the engine was a Crescent

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    I figured it would be in the 50-60 hp range (stock) especially after racers would fine tune it. One thing about it is that I think it was based on the Archimedes Monark 35 and 45hp models If I'm correct. These were nice fishing motors that were 500cc and three cylinders. The strangest of this line though, was the Drive-45. This was a inboard/outboard set up with a tractor unit (backwards prop).

    ( I'm glad they chose Archimedes for a name instead of Da Vinci ... Leonardo was a great artist and visionary, but he was a real lousy physicist when it came to engineering !! LOL)

    Da Vinci: The inventor of the 1000lb wheelchair and no where close to the genius of Archimedes!!!!!

  6. #16
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    There's a U-Tube video of a Crescent out there.

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

  7. #17
    BRF Team Europe Member Per's Avatar
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    There is actually several




    Very nice engines, but I'm quite biased as I own at least three Volvo Penta / Archimedes Penta VP700 and they were from the same factory (they are not related from a technical point of view though)

  8. #18
    BRF Team Europe Member Per's Avatar
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    Default More video...


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    Are they piston port engines, or is there a reed vale hiding behind the carbs?

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

  10. #20
    Team Member Frank Volker's Avatar
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    I recall a C-Hydro race at St Joseph, MO (1966/67 ?) in which Bill Seebold was driving a Crescent. It sounded like it was having fuel problems, but about 1/2 way through the race it cleaned out and looked like it had 5 mph and a ton of acceleration on everyone. I don't recall where he finished or if he finished at all, but when it was running it was in a class by itself.

    Here's what I recall about the alky Crescent:
    1. Pure piston-port intake with no reeds.
    2. Central combustion chamber.
    3. Slightly domed pistons. One ring(?).
    4. The compression was very high.
    5. The bottom exhaust passage was angled upstream slightly.
    6. The exhaust inside the housing was a straight pipe and short (6" or so) megaphone.
    7. The entire engine assembly with housing and lower unit was very light.
    8. The cylinder walls were chrome plated (I think).

    Overall, I thought it was a very impressive engine, but then I've always been a fan of 3-cylinder engines. The only possible show stopper for me would be the chromed cylinders.

    Frank
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