Drawings for Mercruiser installation

[mikael]

Hello.<br />I am building a 38 feet boat by my self and most of it is done except the engine room. I'm planning to use one Mercruiser 5,7L V8 or bigger, maybe Mercruiser 496. My problem is that I don't know how to build the beams. I don’t know the height, wide etc. So I hope that somebody maybe have the installation drawings for Mercruiser 496 and big block? Tank you in advance!<br /><br />Mikael from Sweden

 

[Don S]

Re: Drawings for Mercruiser installation

Are you planning on using an outdrive? If so, I don't think a single engine, even the 496 is enough for that size boat. Most 38 foot (11.6 Meter) boats are powered by twin inboards with straight shafts or V-drives.<br />But without any information on engine placement and drive line, it's really impossible to say how to build the stringers.

 

[mikael]

Re: Drawings for Mercruiser installation

Hi!<br />The reason that I only planning to use one engines is that the boat don't need to go so fast. And it's cheaper! <br />I'm going to use sterndrive to the engine. Thank you for your answer.<br /><br />Mikael

 

[rodbolt]

Re: Drawings for Mercruiser installation

wow your asking for coupler failures. thats a lot of hull for a single outdrive. if I were you I would contact mercrusier direct and send them your blueprints and allow tech services to assist you. they have a dept that designs engine installations. one of my former service reps was transfred to it years ago. you may be better off with the engine fwd and a jack shaft set up.<br /> good luck and keep posting

 

[tommays]

Re: Drawings for Mercruiser installation

your long term costs are going to be much higher with a sterndrive <br /><br />if you have any chance to go shaft drive do it <br /><br />a sterndrive is great beacuse of the space it saves but there are so many parts that in the water that have long term repiar needs it costs much more over its life time<br /><br />tommays

 

[Don S]

Re: Drawings for Mercruiser installation

What I would recommend is first purchacing the engine and drive you plan on using. It includes the necessary heights for the transom cutout in relation to the angle of the transom, and this does vary for different types of drives.<br />Then, depending on transom angle you need to know which engine you will be using for the hight and distance between the stringers. Big blocks are farther forward than small blocks.<br />Also realize that you MUST have between 10 and 16 degrees of transom angle to use the outdrive system. If you have 0 transom angle, then you can not use the outdrives......even a low speed. The engine would be extreamly bow down and the drive would not be in the water enough for control.

 

[mikael]

Re: Drawings for Mercruiser installation

Hi!<br />Thank you all for your comments.<br /><br />I’m very good at building boats but when it comes to the engines I’m not so good any more, so of course I’m listening to all suggestions I will have.<br />If I want I can have an engine room that is 3x3 m big, for the moment it’s 2x3 m, 2 m long and 3 m wide. The stern is 90 degrees compare to the bottom, but I’m going to put a piece outside the stern so it will be 98 degrees on the outside of the stern and the stern will be about 7 cm (2,76 inch) thick there the possible sterndrive will be fastened. For the moment the stern is 5 cm (1,97 inch) thick. Transom dead rise 20 degrees.<br /><br />My problem is that I not have money for engines right now, so for the moment I want to build as much as possible finish and prepare as much as possible so when I have more many I only need to buy the engines and put it inside the boat.<br /><br />Mikael

 

[rodbolt]

Re: Drawings for Mercruiser installation

hello<br /> that is why I said contact mercruiser directly. the transom usually has to be 2" plus or minus 1/8th and flat within 1/16th. but I am going from memory and it may be failing. Please do yourself a favor and contact merc engineering. you may also consider Volvo-penta. you can contact either manufacture by thier websites.<br /> good luck and keep us posted on what you did.

 

[Don S]

Re: Drawings for Mercruiser installation

Here is what is in the Mercruiser installation manual. And trust me, that 10 to 16 degree transom angle is a must. If you don't have at LEAST 10 degrees, you are going to have problems with everything during the installation.<br /><br />

<br /><br />Here are links to drawing for a Volvo 5.7 and an 8.1. Both require the same size cutouts,stringers, and transom specs. as the Mercruisers.<br /> 5.7 DPS <br /> 8.1 DPS

 

[mikael]

Re: Drawings for Mercruiser installation

Hello<br />Thank you everybody!<br />I will do what ever I can with all the information you give me.<br />And trust me... I will have more questions for you later! So I hope you can help me more in the future!<br /><br />Regards<br />Mikael from Sweden