GOOD IDEA ??? [car engine in a boat]

[Sceptre]

basicaly im sick of the outboard it has problems starting all the F^^* time and it doesnt pull fast I work in a auto shop so I got this idea [drawn pic] and i kno you ppl said that marine engine can ceep high RPM level for a long time and it might be a problem for cars engine to be redlining all the time so dats why Im going to install [ FIG 1 ] so i wont need to rev it and to cool im going to ceep the radiator and rad fan any ideas? feel free to post drawings oh and the brown things lol engine mounts I was too lazy to draw

[Externet]

No need to redline at all. Choose the propeller properly.
You may end with more problems with a car engine instead. Done third world style, seem reliable in Asia. No transmission complexities, just a shaft overboard.
Seems the full access to everything instead of being buried in a hull makes a difference in keeping it healthy.

http://upload.wikimedia.org/wikipedi..._tail_boat.JPG

http://www.msphoto.ca/images/thai%20...-phi-boats.JPG

http://www.mrnaz.com/getfile.php/CIMG3666.JPG?get=26251

http://www.io.com/~johnw/thlongtail.JPG

http://www.paulsthaihouse.co.uk/imag...eapcharter.jpg

[Village_Idiot]

Shouldn't be too big of a deal, many marine gasoline engines started life as automobile engines. I believe Merc's 5.7 engine is a marinized version of the Chevy 350cu. in. engine, etc. Marinizing just means changing a few electricals to make them more weatherproof, maybe reversing rotation of the engine, and in fancier cases, changing cam profiles, valve settings and intake parameters.

I think cooling will be your biggest issue. You may end up having to do some sort of water-to-water heat exchanger in lieu of your water-to-air radiator. OTOH, may not be a problem if engine loads are not too great and weather is not too hot.

I've seen many clean engine installations underneath a cover that doubles as the helm/console; however, that can trap radiant heat from the engine and cause overheating if you do not have sufficient cooling to begin with. Think about placing the radiator in a tub of water and exchanging the water frequently with bilge pump or similar.

[hoytedow]

The biggest issue is marinising the engine against spark threat. Start with the alternater and work your way through the rest of the alphabet.

[alan white]

The way it's drawn, the prop will turn twice as fast as the engine. I'd reverse those pulleys.

[hoytedow]

The floor of a metal hull can become the radiator.

[gonzo]

A new outboard would be easier and cheaper. You also need to add a thrust bearing, cutlass bearing, strut and gear box. The hull has to be modified structurally. Also the CG may change enough to make the boat handle badly.

[u4ea32]

You really just need to buy a new outboard motor. Yours sounds totally worn out.

Car engines in boats are simply inappropriate.

There are all the Coast Guard required items (for your own safety, so you don't blow up and die). These are for marine applications, so they are not the same as car applications, and for every aspect of the engine other than the block: the cam shaft needs to be different, so you don't suck water up the exhaust into the cylinders. The exhaust manifold needs to be water jacketed so you don't get too much heat, leading to fires in the engine compartment. The alternator and starter both need to be different, so no sparks happen, leading to those dramatic, exciting, shock and awe, and deadly events of the boat exploding. The carburetor needs to be different to avoid fuel dripping onto the engine and into the bilge. The oil venting needs to be different to avoif the explosive oil mist from killing you.

Getting the shaft and transmission and engine properly aligned to avoid vibration, and avoid wear, is not impossible but LOTS of people get that very wrong, leading to sinking, expense, and that old death thing again.

Outboards are actually designed for boats. That's why they are the way to go for a boat.

[Squidly-Diddly]

bottom of the boat hull, thus the need for spark-less Alternator and other electronics.

I think that is the big reason for the expensive Marine eletronics, not so much the wet/salty enviornment.

I believe the Out-In-The-Open nature of the '3rd World installations' is what makes them safe from gasoline fume EXPLOSION.

[u4ea32]

For sure, the risk of death by explosion is the real key to why car engines don't go in boats.

The wet salty environment also matters. Everything will get wet some days.

The raw water cooling system, or closed cooling system, also makes for a big difference.

And the way water can come up the exhaust is nothing to sniff at.

[Ramius41]

Sceptre

How big is this boat?...I have put a number of car engines in boats for years...mainly big block chevies but a couple of small blocks too...The problem with a boat that has had an outboard on it is what type of drive do you want?...Stearn drive , jet pump or V-drive?...if you are going to enclose the engine you will need a spark arrester and a good ventalation fan! Also exhaust will/could be a problem...you will need a marine exhaust manifold or marine headers if you are going to enclose the engine...if it will be an open engine compartment you could use headers but you will have to check on where you plan on running the boat , most states require you to run mufflers or water through the exhaust...cooling the motor wont be a big problem because the drives have provisions for cooling..

[Sceptre]

Originally Posted by Ramius41

Sceptre

How big is this boat?...I have put a number of car engines in boats for years...mainly big block chevies but a couple of small blocks too...The problem with a boat that has had an outboard on it is what type of drive do you want?...Stearn drive , jet pump or V-drive?...if you are going to enclose the engine you will need a spark arrester and a good ventalation fan! Also exhaust will/could be a problem...you will need a marine exhaust manifold or marine headers if you are going to enclose the engine...if it will be an open engine compartment you could use headers but you will have to check on where you plan on running the boat , most states require you to run mufflers or water through the exhaust...cooling the motor wont be a big problem because the drives have provisions for cooling..

why not just use original radiator with fans ?

[Ramius41]

Originally Posted by Sceptre

why not just use original radiator with fans ?

You can use a closed loop setup but you need good airflow. I have used that setup in a jetboat before and it seems to work well. How big is your boat?

[Sceptre]

16 feet chrysler

[Ramius41]

thats going to be a tight fit!...lol what size motor? and what type of drive will you be using?