possible engine upgrade

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DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Happy holidays everyone!I have a question about a possible engine upgrade. I bought a really clean 1978 bay liner Saratoga a few months back with a Volvo aq225d engine and a 280 out drive. The boat has 1600 hours on her and was stored in doors. She runs better than any boat I have owned and am pretty much in love. Its 25 feet long and looks like a cabin cruiser more or less. So my question is I can get my hands on a aq265d with 300 hours on it that runs great. Would I notice much of a power gain if I swapped them out? Also is a 305 a good motor for my boat?
 
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DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Re: possible engine upgrade

Sorry for confusion I meant I could get a aq260 engine
 
M

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: possible engine upgrade

This is VERY general and second-handish information, but I think you are on the right track for a straight forward upgrade.

The AQ225 and AQ260 are in the same VP family, the AQ225 is a 5.0l (305CI) GM and the AQ260 is a 5.7 (350CI) GM. The external components and drive unit connections on each should be the same. I am basing this on the fact that they are both covered in the same VP owner's manual, and that they are same famly of GM small block engines used by VP in your vintage of drive/engine. I bet it is one of the easier swaps on the boating univers. The recommended drive ratio is more than likely same for those 2 engines, and you would probably be able to go up a pitch size if you are reaching top RPM's now.

As far as 305 engine being good, that is what you have now so it seems like it is peforming well for you! A 350 would be even better for a boat that size. Although I cannot give any real cost/effort to benefit realization analysis, I would bet you could feel the difference in the first cruise :) But sometimes it is best to leave well enough alone as swapping can always introduce problems.

I tried to attach the owners manual PDF but it is too large.

Go to this link and type in AQ225 for engine type, it should bring up a list of downloadable manuals for you...:

Publication search - Publication Search : Volvo Penta

Download it and you will see that the AQ225 manual covers the AQ260 as well.


Got pics? I boat vicariously :) plus I am a little bit nosy....
 
D

DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Re: possible engine upgrade

A lot of great info ! Thanks for the link and your right it all looks like it can be transfered . I uploaded a pic but it won't open now that its on the thread . I will try it a different way . Its a cool old school boat I have only seen one other before as its not the fly bridge version but is still a hard top helm
 
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DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Re: possible engine upgrade

I plan on renaming her. Mss Stephanie just doesn't fit :)
 
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jeffnick

Senior Chief Petty Officer
Joined
May 24, 2004
Messages
695
Re: possible engine upgrade

I have a 260A w/ 250 drive. I love the simplicity.
Why do you want to re-power...to get poorer fuel economy? To go faster and impress your friends? Just because you want to screw with it? Why not go balls out and put in a 383 w/ over 300hp?
 
C

captmello

Captain
Joined
Jun 30, 2008
Messages
3,849
Re: possible engine upgrade

I don't think you'll notice much difference in speed or performance. If it were me, I would do a compression test on the current motor. Those results whould go a long way in helping you decide if a repower is necessary or not.
 
Tail_Gunner

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: possible engine upgrade

Here's where a 383 would be a great improvement. I believe most of the marine part't will bolt right up manifolds etc...Wait for Bondo's reply..Now why a 383 you would be effectivley doubling the horsepower and tourqe of that old 305..and more than probably the same econ....On big question would be will the drive survive that much power..Nice boat
 
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D

DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Re: possible engine upgrade

Thanks for the info guys. The reason I was curious about changing motors is the aq260 would be almost free and if it would be a better fit for the boat than I would do it . For me this boat is a cruiser , camp in on a weekend with wave runners in tow. I have never had a boat with more than 200 hours on it too that's what also had me thinking given this other motor has only 300 hours on it. My motor runs amazing with the 1600 hours and doesn't burn oil . If the change would cause more fuel consumption with minimal power increase than I assume not do it. Is 1600 hours even that much wear for a cruiser like this?
 
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DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Re: possible engine upgrade

The 383 idea is interesting! More power and torque with same fuel economy? :)
 
Walt T

Walt T

Lieutenant
Joined
Mar 16, 2002
Messages
1,369
Re: possible engine upgrade

Guys he just asked about a power gain. He didn't say he was looking to race in the IHBA series. Nothing wrong with replacing a 5.0 with a 5.7, especially when he says the 5.7 is almost free. However I recommend rebuilding the 5.7 over the next year or so then just keep it in storage until you think you need it. Why tear out a perfectly good motor? By the way, send the 5.7 to a machine shop, don't let a marine shop rebuild it. Not dissing the marine shop mechanics, its more cost effective to have it built by pros. Most established machine shops will warranty it no problem where a small marine shop can't afford to warranty it.

The 5.0 is small for that size boat, a 5.7 may or may not gain a little power. How does it perform now, and what would you like to achieve? My guess is you would like a higher cruising speed of say 30 mph and not have the engine screaming at 4000 rpm to do a decent cruise. Truth be told, a 5.7 by itself won't get you there. The 383 is a custom built stroker motor that may or may not get you there. The beauty of the stroker is that it will fit right in there with no modifications for the most part.
Stay away from any mechanic who says they can add a cam and make it suddenly put out 75 more hp.
Don't do anything to the perfectly good motor for now, enjoy your boat and decide exactly what you would like to have your boat do. Maybe just adding trim tabs will make a world of difference.

That is one nice boat! Just goes to show there are some really well kept older boats out there.
 
D

DJ87

Seaman
Joined
Dec 20, 2010
Messages
65
Re: possible engine upgrade

Thanks guys for the comments. Walt your right the boat does tach up to a high rpm for light cruising speed . The boat does have trim tabs but feels a little underpowered , especially loaded with food ,fuel and people . I'm going to attach pics of the aq260 and the outdrive . I thought it was a 280 outdrive but is a little different than my 280
 
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