SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: som beach on June 10, 2010, 12:32:36 PM

Title: Jet boat motors
Post by: som beach on June 10, 2010, 12:32:36 PM
Hey guys!!

Just joined this forum today.  Looking forward to exploring a bit.

I have a question that may be kinda stupid, but I don't know a lot about jet boats.  Also, please don't take offense to this question.

Are the engines that you guys run in your boats marine engines, or does that matter in a jet boat?  Would a guy be able to easily drop one of your engines into an I/O?

Main reason for my questions, I have a 24' Arriva I/O with a 7.4l/Bravo 1.  Over Memorial Day weekend, I dropped a valve in cylinder 1 and trashed my motor.  I've been quoted 5 or 6 G's to rebuild it.  I am trying to consider all of my options on getting back on the water.  We run a marine and automotive upholstery shop, and so I am considering buying a project boat that has a decent big block and using the motor in my boat, restoring the jet boat and selling it less its engine to try and recoup some of the cost of the motor.

Any thoughts on this as an option?

Thanks
Title: Re: Jet boat motors
Post by: Brendella Pickle on June 10, 2010, 12:48:44 PM
My brother has probably the identical boat 24' Arriva open bow red... He has a street 454 in his with a mild cam. Has been run this way for 6 years.
Title: Re: Jet boat motors
Post by: electrowoman on June 10, 2010, 02:16:57 PM
If I were you I would pick up a junk yard engine in decent shape and rebuild the short block.
Transfer what ever parts you can save from your marine engine and you'll be back on the water.   

Use your cam and lifters, distributor, heads (f they weren't destroyed)and you'll have your
performance without all the $$$$

You can spend $$$$ next summer  ;D
Title: Re: Jet boat motors
Post by: trmn8ter on June 10, 2010, 04:17:40 PM
6G is insane, I dont have that much in my 496. How much did the motor break? Can you repair the head and get a new block and a replacement piston? I be willing to bet you can be on the road for 3g if you do your homework.
Title: Re: Jet boat motors
Post by: 88CARRERA on June 10, 2010, 04:28:44 PM
i have a chevy 454 2 bolt i took apart, it was running just have it hot tanks, honed, get some bearings a valve job, waynes engine in riverside quoted about 600 for all that. put it back together and get an intake and carb

its a factort hi perf pass

300.00
Title: Re: Jet boat motors
Post by: som beach on June 10, 2010, 09:13:06 PM
Yeah,  I'm not sure if the block is salvagable or not.  I have not torn into it yet, but I know the head is destroyed.  The shop I took it to to get checked out, used a bore camera to look at the cylinder.  The piston is toast, and busted apart and jaged.  The head was beat to hell, and the cylinder walls were gouged.  I truly believe I can get back on the water for much less then 5 or 6, but since I am rebuilding/replacing I am going up in HP by at least 100.  The stock HP was 330, and I would like to be in the 400-450 range when I'm done.  If I hit 500, I won't cry too hard.  If the block is salvagable, I will have to replace all the pistons anyway, as the block will have to be bored at least .030 over.

Thanks for the replies!!
Title: Re: Jet boat motors
Post by: electrowoman on June 12, 2010, 03:18:53 AM
If you're on a budget you could go with one sleave and one new piston for the short block.
Title: Re: Jet boat motors
Post by: 74 howard 21rc on June 12, 2010, 09:21:55 AM
The main thing you got to watch for in the big HP is the cam.A lot of cam will destroy your out drive.Its when you put it in gear from forward to reverse,high idle because of the big cam.
Title: Re: Jet boat motors
Post by: electrowoman on June 17, 2010, 11:06:23 AM
The main thing you got to watch for in the big HP is the cam.A lot of cam will destroy your out drive.Its when you put it in gear from forward to reverse,high idle because of the big cam.

I thought we were talking jet boat?  They're gear exempt.   ::)
Title: Re: Jet boat motors
Post by: dirty dave on June 18, 2010, 08:55:40 AM
Your 7.4 might be repairable as others a stated or traded in as a core?  My shop builds them all the time 396,402,427,454's thru 572's a454 done right starts at about 3K plus the insedentals like big oil pans your peripherals ,carb,ign should be reuseable, all it takes is bread$ We only use top quality parts like actual marine S/S head gaskets not auto fel-pro's. The Dirty One. (951) 764-4802
Title: Re: Jet boat motors
Post by: CHROMEY on June 21, 2010, 03:49:10 PM
Quote
I thought we were talking jet boat?  They're gear exempt.

he wants to put in a cheeper jet boat motor in his I/O boat
Title: Re: Jet boat motors
Post by: som beach on June 22, 2010, 01:20:23 PM
I'm just trying to get the most HP and bang for my buck.  Thought process was, if I could buy a jet boat that had a decent running BBC with 400+ hp, but needed work elsewhere like upholstery, I could transplant the motor into my boat and restore the interior and hull of the jet to sell it less motor.  Help recoup some of the cost of getting my boat back on the water.  If this is the route we take, I plan to run the jet boat a couple times, and hell who knows, I may fall in love with jet boating and sell the I/O 8)  Time will tell.  Nothing is going to happen until next winter/spring.  We are a cash operation and will take some time to fund this project, even if we rebuild the motor we have.
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