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Alternatives for 7.4 mpi vdrives?

V

vroomZOOM

Regular Contributor
Hello,

I am thinking of buying a boat (2001) with original engines. I am pretty sure both engines are toast, and the price is therefore proportional. What engines would be best for it? I could rebuild the engines in it, or switch to a different engine. As for switching to another engine, I want to go with a 8.1s horizon or maybe a 496 MAG. Also how hard would it be to convert to a diesel, and which engines would work? I would probably need a new tranny if i go that way. Would a new tranny just bolt up and fit in the same place, or is it something totally different? I wouldn't mind making new engine mounts. As for the 8.1, i know i can get a decent truck block for a good price, would the 7.4 ecm, harness, cams, manis, and heat exchangers work on the 8.1 blocks? I have a buddy who can really manipulate those ecms (hours too;)) so he would be able to reflash them as needed.
 
Wheeew! Got yourself an expensive proposition there. Usually, replacing in kind is the simplest and cheapest way to go.

Personally, I hate Vee drives! Not only are a pain to adjust the stuffing box, they're an additional maintenance item in themselves.

Jeff

PS: Don't laugh, but a brace of high powered outboards back there might be an option. With a Vee drive setup the weight is concentrated at the stern anyhow.
 
Before you buy this boat, spend a few hundred and have it checked by a certified Marine Surveyor. They will tell you if the boat is actually worth the $40,000 cost to repower. If you are going cheap and using wrecking yard truck blocks, then good luck to you. I would see if you can get remanufactured long blocks of the same type and swap over the components from the old engines. The exhausts you'd want new. That would be the best compromise of cost and complexity. That would put you more in the 15,000 range, all in.
I would ask what caused the engines to be "toast". Abuse? Immersion? Rust? What impact did those causes have on the rest of the boat and its running gear? What other issues are there with the boat? Structure? Plumbing? Electrical?
 
It would have helpful if you had told us the boat's make, model and length so we could at least speculate as to the suitability of the stock engines and the potential case for diesels...
 
jeez the boat's cheaper than the marine survey (just kidding). So my question didn't get answered... will the 7.4 harness and ecm work? Also, are the 7.4's powerful enough for a 2001 wellcraft 3300? Not sure about dumping 15000, but 10k for sure. I could also rebuild the 7.4's that are in there, but are they enough power? I need something to wrench on for at least four months during my summer break. Yeah, what caused the engines to toast? not fully sure if they are toast, they mighta survived, but i plan for the worst. yep they thought it was too hot in the engine bay so they decided to take a swim. (brine) I know the genny's toast but ive rebuilt a handful of those, that is not a problem. not sure how high the water was, and if it got in the intake, but i am ready to replace all the wiring - no big deal for me i have wired some stuff with a little more than a couple of ecm's. Has the ecm survived? yes it has, I talked to buddy and he said that even if they are fully dunked in salt water he can rebuild the plugs and pcb. So yeah, stick with the 7.4, or go 8.1? What parts swap over from the 7.4 to the 8.1? diesel seems bizarre. and yes, i will be rebuilding the engines and doing all the work myself - that is the whole point of me buying the boat.
 
fastjeff said:
Wheeew! Got yourself an expensive proposition there. Usually, replacing in kind is the simplest and cheapest way to go.

Personally, I hate Vee drives! Not only are a pain to adjust the stuffing box, they're an additional maintenance item in themselves.

Jeff

PS: Don't laugh, but a brace of high powered outboards back there might be an option. With a Vee drive setup the weight is concentrated at the stern anyhow.
Click to expand...

lol, you think i like them? no... but i couldn't find anything of the sorts with outdrives - the prices for those are way too high IMHO. P.S. I missed a good one, it was a 2000 maxum 3300scr, almost perfect but a tad neglected. One cracked block, but two good BIII's. $8k!!! boat was in really nice shape. I thought it was too expensive lol.
 
sandkicker said:
It would have helpful if you had told us the boat's make, model and length so we could at least speculate as to the suitability of the stock engines and the potential case for diesels...
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Wellcraft 3300. lots of room in the engine bay. I can attach a pic of the engine bay but it is not for the faint of heart.
 
ok i guess ill just rebuild those that are in there if i end up buying them! Thanks! BTW is the ecm and harness the same on the 7.4 and 8.1????
 
I would keep shopping. Sounds like a giant money pit. Rebuilding is always far more expensive than buying reman.
 
I wouldn't even think of small blocks in a 33 footer....

8.1 & 7.4 same ECU - mostly, though they could be flashed differently. the harnesses are usually different enough to warrant buying the one you need if its not the same....

And I would suggest a straight inboard, not a V-drive....they are reliable enough but they can a major pain to get aligned correctly...

Don't even consider a diesel swap......especially 'up north'....
 
o2batsea said:
I would keep shopping. Sounds like a giant money pit. Rebuilding is always far more expensive than buying reman.
Click to expand...

Hmm... So you're saying that there are boats in existence which are not moneypits? I thought that the definition of a boat was a hole in the water into which the money falls in?
 
makomark said:
I wouldn't even think of small blocks in a 33 footer....

8.1 & 7.4 same ECU - mostly, though they could be flashed differently. the harnesses are usually different enough to warrant buying the one you need if its not the same....

And I would suggest a straight inboard, not a V-drive....they are reliable enough but they can a major pain to get aligned correctly...

Don't even consider a diesel swap......especially 'up north'....
Click to expand...

Yay! exactly the info I was looking for! what about the cam, and will it bolt up to the tranny? I don't think I will do an inboard swap, that seems like a lot of work. As for flashing the ecm, my buddy could do that. yeah, i think small blocks in that boat might stress them a tad too much. The reason I went after this boat is that i saw the word BIG BLOCKS. Id rather have a big block running at 3200 than a small block running at 4400.
 
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vroomZOOM said:
Yay! exactly the info I was looking for! what about the cam, and will it bolt up to the tranny? I don't think I will do an inboard swap, that seems like a lot of work. As for flashing the ecm, my buddy could do that. yeah, i think small blocks in that boat might stress them a tad too much. The reason I went after this boat is that i saw the word BIG BLOCKS. Id rather have a big block running at 3200 than a small block running at 4400.
Click to expand...

Here is some more info........ And the only way I would do it....... I purchased a set of 496 Mag HO's which you do not need, for $16K they have new exhaust and oil coolers on them.... with 450 hrs....Straight 8.1s or 496 Mag's will work for your hull...

Drop in ready.... Don't waste your time on the 7.4.....
 
Docksidemarineservices said:
Here is some more info........ And the only way I would do it....... I purchased a set of 496 Mag HO's which you do not need, for $16K they have new exhaust and oil coolers on them.... with 450 hrs....Straight 8.1s or 496 Mag's will work for your hull...

Drop in ready.... Don't waste your time on the 7.4.....
Click to expand...

you mean "I don't need"? I would have bought them, except that i don't own the boat yet. The guys don't want to sell it to me because of covid. Ill definetly keep it in mind tho if or rather when i buy the boat.
 
vroomZOOM said:
you mean "I don't need"? I would have bought them, except that i don't own the boat yet. The guys don't want to sell it to me because of covid. Ill definetly keep it in mind tho if or rather when i buy the boat.
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What I meant is, You, Will not need "MAG HO's"..... Just plain old 496 mags or 8.1s..... I am using the set I have for a repower on a 2000 Formula 330SS... It currently has a set of L29's which are done.
 
The boat sank. That right there is plenty of reason not to get into it. The problem with a submersion is that the water intrudes into every molecule of the boat's systems. You aren't just swapping engines, you are swapping every wire, hose, and fitting. Those V-drives must come out for rebuilding and the stuffing boxes serviced. Every light, every pump, every tank, everything in the kitchen, all the interior (carpets cushions etc) and you absolutely must have the hull tested for moisture content.
So yeh compared to other boats of similar age and design that haven't sunk, this is the very definition of money pit. Have fun with that.
You must really be in love with Wellcraft. To me they aren't all that exciting. By this time in the history they had become bleach bottle cruisers and no longer had the coolness factor that they once had. There are lots of far-more-worthwhile Bertram, Phoenix, Jersey, Chris Craft, even Uniflites and the occasional Trojan that are classics. These can be had for the kind of money that you'll throw at a pair of big blocks, and they're often well cared for and being passed on by owners who are getting too old for them.
 
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The boat did not sink. The engine room filled up halfway with water, but it did not enter the cabin. I would NEVER buy something that had water in the cabin. I have seen many boats where there was water in the cabin, i know what it looks like. There is NOTHING worse than doing upholstery! Doing mechanical work - no problem. Upholstery - NO! Thanks for the advice people!
 
The boat did not sink. The hull filled up halfway with water, but it did not enter the cabin.
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Fixed it for ya. You still have to replace everything below the waterline, which is where they put all the expensive stuff.
 
o2batsea said:
Fixed it for ya. You still have to replace everything below the waterline, which is where they put all the expensive stuff.
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dude, why did you change my quote? i said engine room, not hull! Yes, i do have to replace or rebuild everything below the waterline! Engines, trannys, and gennys, as well as wiring! Yes the fact that the water was only in the engine room fixes one big thing - no UPHOLSTERY!!!!
 
I dunno about that it won't need interior. If it sat for any time with all that moisture inside the whole thing will be a giant mildew Petri dish. Black mold too. I'm sure you've already sold yourself on this project but you should maybe dial back the excitement a few notches and give yourself a chance to think with your wallet and not your heart.
We've all been exactly where you are now. You envision yourself at the helm, sunny day, wind in your face, babes in bikinis, and a cold one in the cupholder. Nice. But imagine the journey from here to there. How many tens of thousands of dollars and hours spent in the belly of the beast? Can you get to that same place faster or cheaper? Maybe look at a new boat and the financing...may even offer you some tax shelter. I'm sure that you've thought this through but it would suck if you got deep into the project and something happens that prevents you from finishing and it becomes a huge burden that you are stuck with.
 
o2batsea said:
I dunno about that it won't need interior. If it sat for any time with all that moisture inside the whole thing will be a giant mildew Petri dish. Black mold too. I'm sure you've already sold yourself on this project but you should maybe dial back the excitement a few notches and give yourself a chance to think with your wallet and not your heart.
We've all been exactly where you are now. You envision yourself at the helm, sunny day, wind in your face, babes in bikinis, and a cold one in the cupholder. Nice. But imagine the journey from here to there. How many tens of thousands of dollars and hours spent in the belly of the beast? Can you get to that same place faster or cheaper? Maybe look at a new boat and the financing...may even offer you some tax shelter. I'm sure that you've thought this through but it would suck if you got deep into the project and something happens that prevents you from finishing and it becomes a huge burden that you are stuck with.
Click to expand...

if its not a deal, i am NOT getting it. The only reason i would get it is because it's a good deal. If it's not, i will go find something else. doing any upholstery is an instant deal buster. Yes i am ready to put 4 months of work, 8 hrs a day into it, but I better be saving thousands, otherwise it is not worth it, i can buy something RTR! Anyways, i like the idea of mold testing, haven't thought about that, i have another buddy who does that for a living so ill consult with him!
 
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