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Engine options to replace 4.3L V6

Posted: Sep 11th, '24, 11:50
by Joef
men - need some thoughts. My dad's B26 w straight inboards is finally in action - and at 85yrs old, im not sure what he loves more, the boat or all the attention he gets at his marina. Since dropping it in the water a few weeks ago, we've confirmed that the stbd transmission, which is a somewhat uncommon Newage PRM750, has an oil leak that we think is coming from the output shaft seal. we're gonna keep pouring oil in the top and catching it in a small pan under the tranny until this fall - then, we'll probably need to pull the engine to fix that seal.

Some other factors - this leaking transmission does not match the portside unit, which is a velvet drive gear. Appears that at some point in the boat's life a new engine was needed on the stbd side and probably due to difficulty in finding a reverse rotation v6, they went w a std rotation engine and used this Newage gear, that i think was designed to have a nearly identical geometry as the velvet drives - so - now the boat has mismatched gear.

Pulling both engines is probably going to be the right move and then giving them everything they need - clean up and paint the engine spaces, etc. But - you know how it goes - you get involved up to a point and you start with "while we're at it". and in this case the logic is "since we need to pull engines, should we match up the transmissions - or - just replace both engines." Other items got mismatched over the years as well. One has a starter on the front of the flywheel, the other on the back. One set of gauges seem to be dead-nuts on, the other set is all over the place - other small things - wiring and breakers that dont match.

I know i just made it sound like the boats a mess - its really not - but the engine situation is weird. Just for fun, we've looked at options to replace - several v8 options might fit in there... and it seems like all of the v6 option are for I/O applications. Volvo makes a 4.3 and Merc makes a 4.5. both look like really nice direct injection units that would fit easily - and have plenty of power for this little boat - but - do any of you guys know if those things can be adapted to straight inboards? Id imagine a new bell housing, maybe water pump...

anyway - boat will be headed to Holtz this winter and Im gonna be calling down there shortly to work up some sort of plan - but thought id reach out to you guys for ideas

JoeF

Re: Engine options to replace 4.3L V6

Posted: Sep 11th, '24, 13:03
by Carl
Motors running well? Dependable? Lots of Blow-by? How's the Compression? How many hours do you think they have? IS it ridiculously high were you feel a need to open them up to verify inner condition to see how much life is left?

If the above passes muster, the question is do you want better performance...I'd say better economy but for the amount of coin to replace a pair of motors and trans its going to be many many hours to get to break even.

So if this is "----" a "PROJECT" you want to do, that is what you should do if it is in your means.

Me...if it ain't broke, don't fix it. I'd pull motors, replace seal. I'd give all hoses, belts, electrical a good once over, replacing whats needed now that everything is easily acceptable. I'd freshen the paint on motors, and engine compartment also change out the wonky gauges. Then put it all back in and get to enjoying the boat.

Project creep is a real thing...as you said, once you start the "while we are at it" the snowball grows and grows. In my experience the money you put into it you'll never see again as an Old boat with New Gas Motors does command much more of a selling price as an Old Boat with Old Gas Motors.

Again, if it is "----" something you want to do to put a smile on your face and your dads, you do what you need to do if its in your means.

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I am came back to edit, removing the "Just" in two places. A smile is way more than Just a smile.

Re: Engine options to replace 4.3L V6

Posted: Sep 11th, '24, 16:29
by JeremyD
I'll also add that when you pull he engines - and have access - replace all the instrument senders - replace the thermostats - replace the belts and hoses. If the engines are running well - then that typically will help clear up the problems - if it doesn't then you at least know the senders are good and won't be cussing yourself for not taking care of when you had easy access.

Re: Engine options to replace 4.3L V6

Posted: Sep 11th, '24, 17:32
by Joef
Thanks guys. Engine blocks are sound. Less than 600 hrs. No blowby. Your recommendations is how this is likely to happen. Cleanup and replace the leaking seal, fix the gauges and go fishing. It is a cool boat. Almost everyone who walks by makes a compliment… he’s definitely not in this for “return on investment “ . At 85, it’s awesome he’s still foolin around fixing a boat half his age. I guess a luxury of that age is that resale value isn’t even a thing.

I gotta post some pictures.

Thanks again

Re: Engine options to replace 4.3L V6

Posted: Sep 11th, '24, 21:27
by Tony Meola
Joe

I agree with what was said. So, the motors are mismatched. As long as the Transmissions are the same gear ratio, I wouldn't worry about it. Now if the older transmission is in question, change it. Otherwise fix it all up and go.