entire engine and drive swap

[travis.email]

Can you guys tell from the fuzzy pictures of this boat i just bought if this cut out hole is too big to swap a 470 3.7 motor and drive into out of my 18' 1979 imperial. The boat in the picture is a 20' 1996 celebrity i just bought that doesn't have a motor or drive. I haven't seen it yet so these pictures are all i have for speculation for now. I am not sure what version of mercrusier drive i have but i can look if it matters. Its the one that came orignally with my 79 model 470 setup. I don't know what used to be in the celebrity before or much about it other then its supposed to be solid and is a 20' x 8.3' bowrider 1996 model.

Thanks for your help...

 

[HT32BSX115]

Re: entire engine and drive swap

That's a standard Mercruiser cutout. Looks like it was drilled for a Bravo. (do the newer Alphas have the top bolts?)

Just about any Alpha or Bravo will fit. A newer OMC Cobra or Volvo SX will fit too.

You might need to relocate the front engine mounts a little though.

The 470 (other than the other disadvantages) might be a little anemic for a boat that size...


Cheers,


Rick

 

[Haut Medoc]

Re: entire engine and drive swap

Welcome to iboats.....
Mercruiser hole, the 470 will fit, but don't waste your time....
Get a 5.0 or better yet a 5.7, your wallet will thank you in the long run.....​

 

[Bondo]

Re: entire engine and drive swap

(do the newer Alphas have the top bolts?)

Ayuh,..... Sure Do......

Mercruiser hole, the 470 will fit, but don't waste your time....

Ditto,........

A 470 Isn't worth the Effort involved,.....

 

[TilliamWe]

Re: entire engine and drive swap

Ditto +2, forget the 470. That bilge is set up to take a V engine, put a V8 in it!

 

[Robj]

Re: entire engine and drive swap

There are many posts regarding the 470. Do a search and then I think you will consider something else. Plus the 470 would be too small for a boat that size. Go for a 305 or 350.

Have a great day,

Rob.

 

[travis.email]

Re: entire engine and drive swap

... The main question is how slow would the 20' openbow 1996 celebrity be with just 165 HP 470?

Below is just the background stort of the two boats.......

I am sure you guys are going to laugh at me for this but for now its a matter of principal that i use the 470 if i can i already have it and have been using it in the other boat last year I already read alot about the 3.7 I think i will be ontop of all the problems before it would go in the new boat. It needs to come out now anyhow for a flywheel and other upgrades. I have a like new cam for it to make sure the water pump drip will stop for awhile and a Aux electric water pump to help with flow at low engine speeds and a extra 3" heat exchanger to loop in. Along with a real marine altenator. The replacement cam came with the lifters caps chain sprockets tentioner ect... so I am thinking about throwing one of the $450 ebay engine kits at it with pistons oil pump and everything as well for the fun of it. So with all of this aside how slow is it going to be then with the 165 hp? I like the idea of it not using too much gas.. keep in mind it has never over heated on me before this is all just to avoid future problems. The only current problems are 10" of teeth missing from the flywheel and a small drip at the front engine weep hole. I bought it with the bad flywheel i have just been carrying a breaker bar to move it past the spot when it gets stuck there. lol The people before me just put a new starter on it and cut away the bad teeth some how the new starter has managed not to get damaged yet with this system. ?? I have a good flywheel to replace it with during the swap.

 

[Don S]

Re: entire engine and drive swap

That's a lot of boat and deep V for a 470. Even at 165 hp, you need TORQUE, to get it on plane. You might not even be able to get it on plane. If it does get on plane, then at least you would have a usable boat.
But the only way you are going to know for sure is to install it and give it a try. Sure sounds like a waste of money to me.
Find a little 17 or 18' boat for the 470, put a 5.7 in that boat.

 

[travis.email]

Re: entire engine and drive swap

So how do the 21 foot cabin cruisers that come out factory with a 470 make it around? Are they lighter or just shaped different? I am not against getting a different prop.

 

[Bondo]

Re: entire engine and drive swap

Ayuh,.....

Sell the 470,.... By the Part will bring Alot of Money, rather than as a Complete broken motor.....
Then take the proceeds,+ Buy a V8........

 

[travis.email]

Re: entire engine and drive swap

Would the biggest trim tabs that would fit assure i would be able to get on plane in some amount of time.

 

[Bondo]

Re: entire engine and drive swap

Would the biggest trim tabs that would fit assure i would be able to get on plane in same amount of time.

Ayuh,....

I Doubt a couple 4X8 sheets of Plywood would even be Big enough........

100+hp in a 20' boat is a Major Difference..........

 

[Don S]

Re: entire engine and drive swap

Like I said before, if you don't want to listen to reason, then put the 470 in the boat, and come back and tell us how it worked out.

 

[krisnowicki]

Re: entire engine and drive swap

If money is the worry g to a junk yard and rip a 350 out of a truck and then marine- ize i with a starter, alternator, and so on. Or depending on where you live you can usually find good deals on craigslist. I have the same size boat you do but about 3-400 lbs heavier and i had a 350 and now have a 305 in it... and I miss the 350 buy a 350 they aren't to expensive are parts are everywhere. Also, as to gas usage you may not use as much which will save you a couple of dollars a week but... The only thing that will be going fast is your engines life because of all the rough wear

 

[Don S]

Re: entire engine and drive swap

If money is the worry g to a junk yard and rip a 350 out of a truck and then marine- ize i with a starter, alternator, and so on.

He needs ALL of it, drive, transom shield, exhaust Y, and engine.
Not just an engine.

 

[Walt T]

Re: entire engine and drive swap

I'm with Don, I'd like to see how it turns out. Seriously, he'll change usernames and them come back "It won't plane!"

 

[180shabah]

Re: entire engine and drive swap

But with a turbo, that 3.7 will scream and make big blocks cower in fear

 

[superpop]

Re: entire engine and drive swap

I would look at the big picture here and quite tripping over a buck to pick up a dime. When you sell the boat in the future you will get a heck of a lot more for it with a newer motor that is sized accordingly vs a scabbed together motor that is not appropriate for the boat unless you like to troll all the time. You will use just as much gas and the smaller motor will have to work harder to get the same results. If it is a nice boat you are only devalueing it and it will be harder to sell when you get frustrated with the lack of performance. I have a 19.5 foot wellcraft open bow with a 4.3L and I would love a V8 but I am pretty happy with what I have, you have the option now, I would sell the 3.7L along with the other parts as a complete motor and then pick up a cheap 350 along with the other parts mentioned. That looks like a lot of boat for 165HP nevermind the lack of torque.

 

[Don S]

Re: entire engine and drive swap

But with a turbo, that 3.7 will scream and make big blocks cower in fear

Yea, for the first 45 seconds, then all you see is this:

 

[travis.email]

Re: entire engine and drive swap

I have decided to start parting out my 470 on ebay and start looking for a marine v8 and outdrive. So there is a big diff between a 305 and a 350. What if i was to buy a compleate 228 marine 305 that runs with a cracked block leaking outwards and move the marine stuff from it onto a good automotive 350 where would i be then? my drive is in really good shape but i guess i need to sell it to get the v8 gear ratio then?