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  1. #1
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    Blowout ring (needed?)

    Guys,I have a comp viking with 2.4 offshore and jackplate.I have always ran a twin pinion speedmaster lower.This year I am going to a shifter lower, with bobs nose kit, and a tork tamer tab.I have a blowout ring to put on this unit.My question, is it needed, will it be faster or slower or just doesent matter?.I will be running a 28 offshore cut and a 28 cleaver.The unit is stripped for paint and now would be the time to install it.
    Last edited by outasite; 02-21-2012 at 02:34 PM.

  2. #2
    Join Date
    Jun 2009
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    Middle USA
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    I purchased a cleaver from an old VP racer. He used a blow out ring sometimes on his props. He said it helped when cornering some. I dont think you will need it. I do not use one. One problem with the blow out ring is if not set up correctly they can rub on the prop. He had a prop with a crack in it and you could see where the blow out ring was rubbing on the cleaver.

    Id test with and without it and make your own decision.
    L6fan57-88

  3. #3
    How long is the gearcase with the cone installed?

    What type of ring are you considering?


  4. #4
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    From tip to tail it is 171/2 inch,That is with the bobs kit installed.The ring is also from bobs,it is to be put on with epoxy.I just dont want the cross section of the bullet to be any larger than what is needed.I quess i could try it without a ring, and add later if needed.

  5. #5
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    http://www.bobsmachine.com/Products/blowoutring.cfm

    This is different than I was thinking. Does this just extend the rear of the gearcase.

    What I was referring to goes under the prop and make a OTH cleaver into a Thru Hub CLeaver.
    L6fan57-88

  6. #6
    Join Date
    Dec 2002
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    Beautiful Lutz Florida
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    There are a couple of problems running a bob's blow out ring. 1st. You have a prop. clearance issue so, you have to either run a thick thrust washer or either a cleaver or drag style prop. 2nd. The ring REALLY needs to be tack welded on. If it comes off, Bad Things Happen! I know what they say that you can epoxy it but, I wouldn't!!!!! Bob's cones on a 200 case are good for around 110 (+/-) depending on your hull so IF you DO need a B/O ring I'd suggest the one Mercury makes. It set screws on and WORKS! I have the part number if you need it. Just my $.02 Mike T.

  7. #7
    Quote Originally Posted by outasite View Post
    From tip to tail it is 171/2 inch,That is with the bobs kit installed.The ring is also from bobs,it is to be put on with epoxy.I just dont want the cross section of the bullet to be any larger than what is needed.I quess i could try it without a ring, and add later if needed.
    Is the ring ground off the case you have?

    If it is, I agree with Mike, install the Merc bolt on one, I never figured out the Bob's ring.

    You don't want to be going down the lake backwards saying "Damn, shoulda put the ring on"


  8. #8
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    The unit that i am building is the stock 1979 2.4 offshore 1.87 gears.It never had a factory ring.The 2.4 is ported and has a 225 front half and big carbs it was strong in the day but i dont feel its up to making 105-110 for sure,Im thinking maybe 95.For props I have a steve Smith offshore cut 28 and a worked merc 28 cleaver. Both have good clearence with the ring on.At this point im thinking I may install the bobs ring with epoxey and drill it for two shallow set screws at six and twelve o-clock.We have some epoxy we use in aircraft apps that become one once it sets.Thanks to all for your input.----------One last thought with the offshore mid and very little if any exhaust leaving the hub seems that mite tend to lessen the chance of blowout?
    Last edited by outasite; 02-21-2012 at 02:37 PM.

  9. #9
    Quote Originally Posted by outasite View Post
    The unit that i am building is the stock 1979 2.4 offshore 1.87 gears.It never had a factory ring.The 2.4 is ported and has a 225 front half and big carbs it was strong in the day but i dont feel its up to making 105-110 for sure,Im thinking maybe 95.For props I have a steve Smith offshore cut 28 and a worked merc 28 cleaver. Both have good clearence with the ring on.At this point im thinking I may install the bobs ring with epoxey and drill it for two shallow set screws at six and twelve o-clock.We have some epoxy we use in aircraft apps that become one once it sets.Thanks to all for your input.----------One last thought with the offshore mid and very little if any exhaust leaving the hub seems that mite tend to lessen the chance of blowout?
    The critical speed on a Vking is about 85 mph. Exhaust exit won't have any effect, it's all about how the water flows over the case profile.


  10. #10
    A 1979 2.4 offshore should look like the bottom motor with a stock gearcase, with a blow out ring



  11. #11
    This is what the Merc ring I have looks like. It is not for sale but if you need to try it I can send it to you to try!


  12. #12
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    That looks like my motor all right,mine may have very early production or something, on mine the skeg radius comes all the way to the trailing edge.And no ring, they must have been running short on good ones and put on a production 175 unit.We bought two at the same time had to beg to get them by mid August of 79.Nice picture you must have quite a collection!

  13. #13
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    Thanks for the offer of borrowing your "anti blowout ring",here in Mich its going to be awhile before any testing weather(actually were cooking maple syrup right now)But again, thanks everyone for your help.Bob

  14. #14
    Quote Originally Posted by outasite View Post
    Thanks for the offer of borrowing your "anti blowout ring",here in Mich its going to be awhile before any testing weather(actually were cooking maple syrup right now)But again, thanks everyone for your help.Bob
    No problem, Let me know if I can help. Tony

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