Need help with engine build
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Need help with engine build

  1. #1
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    Default Need help with engine build

    Hi all. I've had a few jets but this is my first in over 10 years and first non Berkeley. I recently bought a 76 18' Southwind with Jacuzzi WJ. Pump has a diverter but other than that im not sure, in the process of pulling it apart right now to see what it looks like inside. I'll do whatever is necessary to make the pump right for the engine I have. The engine is a 468 BBC 2 bolt with steel crank, Speed Pro forged pistons, 990 heads with roller rockers, tunnel ram with Holley 660's and basset OT headers. Cam is a SLR with unknown specs but im not reusing it anyways. The guy who I got the boat from just had the motor rebuilt and heads gone through. From what he say's the line hone was spec'd wrong and it spun 2 rod bearings after only running it about 25 min. I've got the motor apart and everything looks pretty good from what I can tell so far but i'll let the machine shop determine that for sure. Im wanting a good running reliable lake boat and would like to see 70-75 far as speed. From all the searching i've been doing most recommend hyd roller for the cam. With my setup I was looking at COMP cams XM284HR Retro kit. Am I on the right track here? I have no intentions of using different heads at this point even though the 049 i've ran in the past would maybe be better and plan on keeping the tunnel ram set up for now as well.

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  3. #2
    Some guy obnoxious001's Avatar
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    Quote Originally Posted by byronk View Post
    Hi all. I've had a few jets but this is my first in over 10 years and first non Berkeley. I recently bought a 76 18' Southwind with Jacuzzi WJ. Pump has a diverter but other than that im not sure, in the process of pulling it apart right now to see what it looks like inside. I'll do whatever is necessary to make the pump right for the engine I have. The engine is a 468 BBC 2 bolt with steel crank, Speed Pro forged pistons, 990 heads with roller rockers, tunnel ram with Holley 660's and basset OT headers. Cam is a SLR with unknown specs but im not reusing it anyways. The guy who I got the boat from just had the motor rebuilt and heads gone through. From what he say's the line hone was spec'd wrong and it spun 2 rod bearings after only running it about 25 min. I've got the motor apart and everything looks pretty good from what I can tell so far but i'll let the machine shop determine that for sure. Im wanting a good running reliable lake boat and would like to see 70-75 far as speed. From all the searching i've been doing most recommend hyd roller for the cam. With my setup I was looking at COMP cams XM284HR Retro kit. Am I on the right track here? I have no intentions of using different heads at this point even though the 049 i've ran in the past would maybe be better and plan on keeping the tunnel ram set up for now as well.
    1st thing,, align hone would more likely mess up main bearings, not rod bearings. Is the seller's shop checking out the engine? Make sure the problem is identified and fixed so you don't go through the same thing again.

    If you plan on getting the pump done to work with the engine, you should consider that and talk to a pump guy prior to selecting a cam, but running the 990 heads you may want to let the engine turn up to 6000 rpm by utilizing the proper impeller cut.

  4. #3
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    Quote Originally Posted by obnoxious001 View Post
    1st thing,, align hone would more likely mess up main bearings, not rod bearings. Is the seller's shop checking out the engine? Make sure the problem is identified and fixed so you don't go through the same thing again.

    If you plan on getting the pump done to work with the engine, you should consider that and talk to a pump guy prior to selecting a cam, but running the 990 heads you may want to let the engine turn up to 6000 rpm by utilizing the proper impeller cut.

    Thats just what the seller told me. He had a mechanic friend pull the pan and he found the spun rod bearings. I already bought the boat so I have the motor pulled apart in my garage. I'll be taking everything to a local shop I trust to have everything looked over to see whats needed. I'll definitely be talking to a pump guy once I get it apart and go from there. Thanks for the reply.

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  6. #4
    Senior Member fleetimus's Avatar
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    ByronK, are you in the Redding area?
    Is this real or the "Twilight Zone"?

  7. #5
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    Quote Originally Posted by fleetimus View Post
    ByronK, are you in the Redding area?
    Yeah unfortunately I am. Lol
    Ill give you a call later today fleet

  8. #6
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    Default Lies, lies and half truths...

    Believe NOTHING that the seller is telling you... If I've seen it once, I've seen it a thousand times... !st, a BIG first, if the main bearing align hone was/is in fact messed up, throw the block away, it will never be "right" again.... It is possible for a bad main bearing set up to distribute trash into the rod bearings, but more likely you'll find the mains are fine and the rods had their own issues... So many times I see car/truck mechanics that think boat motors are the same as any other "rebuild".... They are NOT.... A jet boat installation is quite likely the hardest thing you ask an engine to do... boats don't "coast" like pavement applications... A motor in a jet boat never quits working hard... That alone is why most "fresh" failures occur.. A failure after "25 minutes" is a very vague statement... On the trailer, on the water, on the dyno???
    Was there any mention why the engine was "fresh"?? What caused him to rebuild it?? Was it blown up when he got it?? Do yourself a favor and start fresh with another block and rotating assembly. Once rods start spinning bearings it is time to replace them... ("Dot" 454 rods w/7/16ths bolts are not a good choice for your application, too heavy)....

    There are many people here on this forum that can point you in the right direction for both your engine and pump, but if you expect to see 70-75 mph plan on spending a bunch on the engine and double that on the pump... 60-65 mph is a lot easier and cheaper to obtain... Or you could always go to "Craig's list" and buy a 100 mph jetboat.....

    Spend the money on a good quality pan and oil pump. Those two items WILL make a huge difference on the success or failure of your project...

    Good luck,
    Ray
    LOUD BOATS SAVE LIVES

  9. #7
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    Quote Originally Posted by Moneypit View Post
    Or you could always go to "Craig's list" and buy a 100 mph jetboat.....


    Good luck,
    Ray
    I thought thats what I did! J/K

    Long story on the whole deal and since I dont know the whole truth no sense boring anyone with it. What he told me in short........he had the heads gone through (they look super clean) and the engine rebuilt. Broke it in on the trailer, so im sure the wear ring is prolly toast, then took the boat to the lake and ran it for less than 30 minutes. Oil pan was leaking so they, being him and his "mechanic" friend pulled the pan to fix leak and there was metal in the oil. They found the #7 and 8 rod bearings were spun. Boat sat with motor on the ground in his garage for the next 4 years to avoid a divorce and now I have it. Considering what I paid for the whole deal im good spending whats needed. Not everything has to be done all at once, I cant believe I just said that lol, so just freshening the pump and do what I need for the motor to be right and I can be on the water next summer and go from there. Right now just trying to figure out were to start and what parts I can/should reuse. Oh and thanks Ray for the advice.

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    Well the seller wasn't being honest or didn't know what he was talking about, SURPRISE! lol Got it apart and no spun rod bearings but looks like it had an oiling problem that damaged a couple main bearings and dinged the crank a little. Crank IS a steel crank and only at 10/10 so that good, I have it in being taken care of now. Gonna pull the pump this weekend and see whats going on with it. Talked to Tom at Jet Boat Performance and I guess they don't make the adapter rings for the Jacuzzi pump that allow you to use a droop or wedges anymore. If anyone has one id be interested just let me know thanks.

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