BBO big end bearing failure?
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BBO big end bearing failure?

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    "Mad" Member Jet Mad's Avatar
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    Default BBO big end bearing failure?

    After throwing 1000's of $$$ at my BBO motor, putting restrictors on every conceivable bearing, cam bearings, push rods and what else I spun a big end bearing - not exceeding 4250 rpm's - I found that the engine builder dropped the spark plug on the no 4 piston (which spun the bearing) and did not regap it. Electrode was closed. Can it be the cause of the bearing failing? (engine builder )

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    Default #4

    Quote Originally Posted by Jet mad View Post
    After throwing 1000's of $$$ at my BBO motor, putting restrictors on every conceivable bearing, cam bearings, push rods and what else I spun a big end bearing - not exceeding 4250 rpm's - I found that the engine builder dropped the spark plug on the no 4 piston (which spun the bearing) and did not regap it. Electrode was closed. Can it be the cause of the bearing failing? (engine builder )
    Was it #4 that failed? Sure, it could cause a failure because the weight of the rod and piston are being "pulled" instead of pushed by fire. The rod cap is not as strong as the upper 1/2 of the rod, so continued "pulling" could distort the circle............How long did it run that way? Was it ever on the water that way, or just on the trailer? Which rod bolts were used?.....Ray

    PS:More than likely the electrode closed because the piston hit it when the bad bearing allowed the piston to travel too far up in the cylinder. So the idea that the plug caused the problem is doubtful. More often it is the other way around.........
    LOUD BOATS SAVE LIVES

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    "Mad" Member Jet Mad's Avatar
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    Moneypit,

    It was on the water when it spun the bearing. The rod bolts are OEM bolts, I am getting some rods from Mondello's (Nascar) rods. If you go according to the firing order on the manifold it is piston #6. Man I am dissapointed.

    Is your boat the blue Kona with the name Moneypit?

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    Default No

    Quote Originally Posted by Jet mad View Post
    Moneypit,

    It was on the water when it spun the bearing. The rod bolts are OEM bolts, I am getting some rods from Mondello's (Nascar) rods. If you go according to the firing order on the manifold it is piston #6. Man I am dissapointed.

    Is your boat the blue Kona with the name Moneypit?
    No. I have a blue Hydroflite, and a blue Tahiti, and a blue Horizon, but no blue Konas......I also have an Olds mild motor for sale. You might look at it as a way to hit the water again while you fix what you're dealing with now.......It is fresh and currently in a Tahiti "test sled" ready to demonstrate on the water to potential buyers.............

    Your problem had nothing to do with a dropped spark plug. More than likely the stock rod bolts weren't up to the task and allowed the distortion of the cap/rod circle....Also, the smallest spec of crap can pollute the bearing surface and it's curtains from there once the crank grabs the bearing. Which raises another question. What type/brand bearings were they?.......Ray
    LOUD BOATS SAVE LIVES

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    Quote Originally Posted by Moneypit View Post
    No. I have a blue Hydroflite, and a blue Tahiti, and a blue Horizon, but no blue Konas......I also have an Olds mild motor for sale. You might look at it as a way to hit the water again while you fix what you're dealing with now.......It is fresh and currently in a Tahiti "test sled" ready to demonstrate on the water to potential buyers.............

    Your problem had nothing to do with a dropped spark plug. More than likely the stock rod bolts weren't up to the task and allowed the distortion of the cap/rod circle....Also, the smallest spec of crap can pollute the bearing surface and it's curtains from there once the crank grabs the bearing. Which raises another question. What type/brand bearings were they?.......Ray
    I have a bunch of BBO parts I'll sell you. Got a motor I never finished assembling. Pat

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    Default Parts..........

    Quote Originally Posted by Wicked Performance Boats View Post
    I have a bunch of BBO parts I'll sell you. Got a motor I never finished assembling. Pat
    Thanks, but currently I have plenty of Olds parts and pieces. When this one sells, I'll finish another, and so on.........It'll be awhile before I need hard parts, and the soft parts, (bearings/rings/gaskets), are kind of on an "as needed" basis. .....Ray
    LOUD BOATS SAVE LIVES

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    Senior Member 1975sleekcraft's Avatar
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    Default 10 qt pan

    i hope you have the bigger pan!
    also run a high volume oil pump!
    i havent seen the exact tolerances since i built mine in 03, but i am running more clearance on the sides of the big end, and i think 3 thousands deep quarter in wide grooves in both the top and bottom of just the big end. all of this can be confirmed on joe mondellos web site.
    goto tech articles, 455 build up. its good stuff!!

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    "Mad" Member Jet Mad's Avatar
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    The bearings are +.20 Clevite's. I have 3 other Olds motors all with "N" spec cranks which I believe is the sought after crank for Olds.

    I am also running a Moroso Marine 10qt Oil pan.

    I order all my Olds spares from Mondello's, but did not order the bearings from them. I am in the process of getting the correct bearings. ARP rod bolts will be a priority on the list.

    Does anybody know what the spec was for the Packajet Olds motors that was built by, if I am correct Hardin Marine?

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    Boat Nut sleekcrafter's Avatar
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    I would bet they were GM crate motors, and they were cheap.
    Upper Midwest Power Boat Association
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    "Mad" Member Jet Mad's Avatar
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    I do not know if they were GM crate motors, I live in South Africa and know of 4 olds engines and I have 3 of them.

    I have been building my motor for 4 years collecting spares, importing etc. I just collected the 3rd engine today - came out of a Kona and is the marine/irragation spec motor.

    I think I should build myself a SBC - 383 Stroker - With supercharger and use the Olds as an anchor.

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    Senior Member Brendellajet's Avatar
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    do yourself a favor and stay away from Mondello. Their parts are over priced and they are not the best to deal with from what I have read. More knowledge & better parts are available elsewhere if you "must" run the olds.
    "He is a lover, not a fighter. But he's also a fighter, so dont get any ideas."

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    "Try it Now!" Tahiti Boss21's Avatar
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    Default

    Quote Originally Posted by Jet mad View Post
    After throwing 1000's of $$$ at my BBO motor, putting restrictors on every conceivable bearing, cam bearings, push rods and what else I spun a big end bearing - not exceeding 4250 rpm's - I found that the engine builder dropped the spark plug on the no 4 piston (which spun the bearing) and did not regap it. Electrode was closed. Can it be the cause of the bearing failing? (engine builder )

    4250 rpm's and your spinning bearings? Something's wrong. Stock setup should handle that, mine has for 30 plus years....
    1992 Eliminator Daytona 21'

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    "Mad" Member Jet Mad's Avatar
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    Brendellajet,

    Any suggestion who I can contact?

  16. #14
    "Mad" Member Jet Mad's Avatar
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    Thahiti Boss,

    I know I have a major problem, some people are turning 5000-6000 Rpm. I was'nt the only one driving my boat, I think the guy got some rough water and just kept the throttle open, you know the story.

    What I am trying to find out is what do I need to do to build a proper BBO. Bearing clearances, comp ratio, cam spec.

    I have stripped the motor down and is going to measure current clearances, comp ratio etc. - get the good people on this forum to point me in the right direction and hopefully get to somebody that knows the Olds engines an give me the correct info.

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