Key Largo - Motor Decision

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boisebrit
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Key Largo - Motor Decision

Postby boisebrit » Sun Jan 28, 2018 9:03 pm

Hi All,

I am getting closer to finishing the hull on my Key Largo which I have stretched to 20ft.

I have a motor from a parts boat it is a 56 Packard 352 marine conversion. It has low hours and I will do a test start soon before a rebuild. I have attached a picture it is about 220hp as far as I can see from the web and believe they were about 675 lbs in the automotive form.

I think the power will be fine and should sound and look great, my concern is the weight compared to other installations I have seen in the forum.

Don't want to sit too low in the water or over stress the hull, also I need to drill the shaft hole soon so the motor decision is becoming a gate item.

IMG_9205.JPG


Would appreciate your thoughts and advice.

Thanks

Bryan

http://boatbuilders.glen-l.com/key-larg ... oise-idaho

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Bill Edmundson
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Re: Key Largo - Motor Decision

Postby Bill Edmundson » Sun Jan 28, 2018 9:24 pm

Bryan

You're fine. My 20'-6" Tahoe has a Yanmar 125. It weighs 675#. WOT is 38 MPH.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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jenko
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Re: Key Largo - Motor Decision

Postby jenko » Sun Jan 28, 2018 11:19 pm

Yes as Bill said your fine 300-350kg is average for v8 installs my v12 is320kg with 72c and casale
vdrive

boisebrit
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Re: Key Largo - Motor Decision

Postby boisebrit » Mon Jan 29, 2018 6:36 am

Thanks for the help that makes the build budget look a lot better.

Bryan

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Bill Edmundson
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Re: Key Largo - Motor Decision

Postby Bill Edmundson » Mon Jan 29, 2018 9:08 am

Bryan

One thing I noticed. The generator/alternator doesn't appear to be sealed. I can't see the starter. It is very important that the electrical system is sealed. Gas fumes in a closed engine compartment can be deadly.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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boisebrit
Posts: 37
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Location: Boise, Idaho

Re: Key Largo - Motor Decision

Postby boisebrit » Mon Jan 29, 2018 9:19 am

Thanks for the heads up, I will will check the starter as well, I am going to change out the generator for an alternator and try and gain a couple of inches in width, will see if I can relocate at the same time and get a sealed unit.

Bryan

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Bill Edmundson
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Re: Key Largo - Motor Decision

Postby Bill Edmundson » Mon Jan 29, 2018 11:04 am

Bryan

I was just thinks that you may want to locate critical items before you invest time and money in the rebuild. A sealed alternator should be pretty easy. But, a sealed starter for an old Packard engine may be a challenge.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

boisebrit
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Location: Boise, Idaho

Re: Key Largo - Motor Decision

Postby boisebrit » Mon Jan 29, 2018 8:25 pm

Bill,

The starter does not appear stock but does not appear sealed at the rear, the only starter I have found so far is a modern gear reduction starter, a lot more sealed but doubt marine rated.

The motor came out of a boat from 1959 wider than the key largo bigger engine compartment and a lot of blowers.

I have attached a couple of pics the current starter and the one I found, I will do some more digging.

Thanks

Bryan
IMG_9759.jpg

Screen Shot 2018-01-29 at 8.05.21 PM.png
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Screen Shot 2018-01-29 at 8.05.38 PM.png

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jenko
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Re: Key Largo - Motor Decision

Postby jenko » Tue Jan 30, 2018 1:37 am

go for the reduction starter they spin the motor faster and are hermetically sealed :D

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kens
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Re: Key Largo - Motor Decision

Postby kens » Tue Jan 30, 2018 4:35 pm

I'll take a stab at it, you posted:

" I have attached a picture it is about 220hp as far as I can see from the web and believe they were about 675 lbs in the automotive form.

I think the power will be fine and should sound and look great, my concern is the weight compared to other installations I have seen in the forum.

Don't want to sit too low in the water or over stress the hull, also I need to drill the shaft hole soon so the motor decision is becoming a gate item."

Marine engines of all sorts are by nature, heavy. you should see the brochure and paperwork for a new Mercruiser fuel injected V6. I checked out one at the boat show, and was grossly disappointed in the weight. OMG !! brackets all over it for a electronic gadgets of some sort, and maybe 20 of them, plus the gadgets, plus the wiring, plus the marine grade stuff to go with it. I did not see any 'weight' savings in this new MPI V6 engine versus a old school V8. Old school = a carburetor and you are done, pure & simple.
Your old school engine might not be as heavy as you think (compared). I suggest you take a 350 chevy in FULL MARINE DRESS and weight it, on a certified scale, it will tip the scale nearly 1,000lbs, then in the same sentence someone will say a Cummins 6-cyl diesel is 'heavy' because it is 1100lbs, yet the Cummins makes 2x the torque, does that really make it 'heavy'?
don't let me get long winded, but if you want the 'old school' look, and you can get parts to support it, then go for it. I think the major key is to get parts to support it, not the weight or HP.
Also notice that the difference in HP to make a boat go faster than 'x' mph is a big number.
Example:
If your old school Packard makes your boat go 40mph, and if you replaced that with a 'similar' old school Chevy, you might get 42mph.
Which 'look' do you want, the Packard, or, the Chevy, for a minimal difference in performance?
Your installation, I think, is more about the nostalgic look than performance. What is the measurement between centers of the motor mounts?
The common engine stringers are 22"-24". Will your Packard sit in there? I offhand think it will.
Drilling the shaft hole should make no difference because the engine itself sits on the CB. The shaft hole, packing box, strut, shaft angle, should not know the difference between a Packard, a Chevy, or a Ford. Keep the stringers at common centers dimension and nothing should matter.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

steves
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Re: Key Largo - Motor Decision

Postby steves » Tue Jan 30, 2018 5:19 pm

Kens,
to concur with what you said, my brand new 5.7L (350) PCM weighed in at 1041 lbs (but that did include the wooden pallet and transporation wood).

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kens
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Re: Key Largo - Motor Decision

Postby kens » Tue Jan 30, 2018 5:51 pm

steves wrote:Kens,
to concur with what you said, my brand new 5.7L (350) PCM weighed in at 1041 lbs (but that did include the wooden pallet and transporation wood).


So, you got say, 65lbs of shipping wood, that leaves you with a new modern engine of 976lbs.
It funny how you so often hear folks say that a small block chevy is 'only' 450lbs. well, yeah, a long block, maybe, but finish it out in 'Full Marine dress' and that is the difference.

My little 3.0L 4-cyl engine in full marine dress with a VelvetDrive transmission is 700lbs. I weighed it. My 4-banger comes in @ 700lbs.
That makes a little 283 Chevy with a 2-bbl carb @ 900 with old log manifolds look like a good deal.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

boisebrit
Posts: 37
Joined: Wed Jul 27, 2011 6:42 pm
Location: Boise, Idaho

Re: Key Largo - Motor Decision

Postby boisebrit » Tue Jan 30, 2018 9:54 pm

Thanks for the feedback, may be a bit wide for the stringers but only because of the brackets welded on in 1959 the block is fine, we can fix that. Will get the motor fired up in the next couple of months before stripping down for a rebuild. Also a great discussion on the actual weight of the motors all in, as a newbie and as every one a lot of hours into the project really appreciate the help.

Bryan

PeterG
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Re: Key Largo - Motor Decision

Postby PeterG » Wed Jan 31, 2018 6:01 am

I think "old school" is preferred over modern because simplicity can make life easier. A carburetor and simple ignition (updated with a pertonix replacement for the breaker points) will be I think more reliable than a fuel injected catalyzed exhaust wonder engine with all the bells and whistles. There's an engineering theorem that says the chance for a failure goes up with the square of the number of parts involved. Granted modern engines are very good at what they do and benefit from improvements like better volumetric efficiency which can be better fuel economy but we're talking boats here and fuel efficiency is not a primary concern.
I think we're all in vehement agreement here, your engine should work just fine. Besides, who wouldn't want to brag they have a Packard engine in their boat?
Murphy's Law: Anything that can go wrong, will go wrong.
Griffin's Law: Murphy was an optimist.

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Bill Edmundson
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Re: Key Largo - Motor Decision

Postby Bill Edmundson » Wed Jan 31, 2018 7:16 am

Bryan

You'll also need a flame arrester on that carb.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build


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