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Thread: OMC’s 4-Rotor Wankel Racing Engine - The Real Story

  1. #71
    Preserving OMC Heritage LIQUID NIRVANA's Avatar
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    Quote Originally Posted by Skoontz View Post
    Thanks Wayne. We heard the cry babies from Mercury screaming very loud back during this juncture in time, everything from what is written here to the questioning of displacement. I have not read the book John suggested regarding Wankel displacement, but in that case, I can see why one might consider a rotary to be whatever the chamber size is times 3.

    It would be really fun to see these engines on a course today with the newer boats.
    There are four of the latest & greatest 1976 OMC Rotary's unraced & complete with Dyno sheets, & still in their boxes out there somewhere & I BET I KNOW WHERE as well. They are VERY DIFFERENT to the originals & would reliably kick serious butt even today.

  2. #72
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    Quote Originally Posted by Mark75H View Post
    I would think the dedicated 4 rotor motors also benefited from being charge cooled rather than water cooled as the early snowmobile converted motors were.

    So as a guess the total weight of the original motors may have been 260 or so and the later motors ... 220 to 240, just as a guess?
    Sam: All the race engines were water cooled externally and charged cooled internally. The snowmobile was air cooled externally and charged cooled internally. By contrast, the Mazda engine is water cooled externally, but oil cooled internally. Oil cooling allows more HP, because the fuel/air mixture is not heated as in charged cooled, but adds complexity, weight and increased friction hp. The bucket and shroud weighed 35/40 lbs as I recall, add the weight of the gearcase and my guess is your guess is a little low.

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    Guys:
    They say memory is the second thing to go. I have been corrected on my story. It was Rich McKinley that barrell rolled at Galvaston, not Bobby Whitt and Bobby Herring won the St. Louis race, not Billy Seabolt.
    Last edited by Rotary John; 05-26-2009 at 05:05 AM. Reason: spelling

  4. #74
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    Quote Originally Posted by LIQUID NIRVANA View Post






    Many thanks to John Sheldon aka 'ROTARY JOHN' on BRF for providing the above literature.
    Guys:
    The picture above on the Johnson Rotary on the boat is the same unit that was on ebay. Note how high the boat sits in the water, NO Engine.

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    Quote Originally Posted by Master Oil Racing Team View Post
    I just made a startling discovery. I was looking for the few pics I have of the rotaries from the Galveston race and came upon some of Tommy Posey and Barry Woods from 1975. I looked at the dates and they were all August 1975. I asked Joe how many times we saw the rotaries run and he said once...at Galveston. This race appears to be Clear Lake near NASA. I am 99% sure. I will try to dig up more info to confirm, but I don't think I ever got a program from that race. More to follow.

    BTW Lars...you may use any of my photos to post on the Swedish website.
    I don't recall this Photo but Aug'75 would be St. Louis time frame

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    Quote Originally Posted by Mark75H View Post
    I know that is what is implied ... I want John to say so exactly and certainly.
    Guys. I can't swear all four of these engines were the latest no thru bolt vintage and even though I know all 4 were dyno tested prior to being boxed up, I don't know for sure the dyno sheets were actually packed in the boxes. Some day someone will find these engines and if I'm still around, I can identify which is what. One thing I don't recall mentioning before, the cast snowmobile flywheels were replaced with flex plate wheels some time in '75 as a weight saving measure.

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    Many thanks to John Sheldon aka 'ROTARY JOHN' on BRF for providing the above literature.

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    Click on the picture and then go to FULL SIZE to make it bigger













    Many thanks to John Sheldon aka 'ROTARY JOHN' on BRF for providing the above literature.

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    Wayne, there it is in your post, it was the Conroe race I was at, I was working the pits for Rick Clausen at that race

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    Seems to answer where Scott. I didn't go to Conroe in 1973, but that must be where you saw them.

    Great info Rotary John. I remember how deep the transoms were at Galveston. I didn't pick up on the photo with the empty motor and how the boat floated much higher until you mentioned it. Some good inside stuff.



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