Dropping a car engine into my boat?!

[mjestey2000]

I know this has been discussed before, but I can't seem to find it in the archives. <br /><br />Why can't I drop an old big block car engine into my boat and maybe upgrade it to a EFI? I know it will rotate in the opposite direction, but can't I just get a counter rotating outdrive? I'll definitely be doing the closed cooling system. What other problems may there be in this?<br /><br />I assume exhaust manifolds will be standard sizes and I'll be able to attach the cooling water to them. Do I need to get another water pump to send the water through the closed system or will the outdrive be able to handle it?<br /><br />Thanks!!<br />Mike

 

[JB]

Re: Dropping a car engine into my boat?!

Moved this post to I/O and Inboards.

 

[Steve135]

Re: Dropping a car engine into my boat?!

Hi Mike, You can do it because you can do anything you want its your boat. But an auto engine has not one part that is marine rated. That means all nuts and bolts will rust in place in a couple of weeks.The block will rust as the paint isn't for marine use! The oil pan will rust thru also.All the linkage on the carb. and butter flys will rust. Dip stick etc.Do I need to go on???????<br />Steve

 

[sloopy]

Re: Dropping a car engine into my boat?!

lets also not forget the starter and distributer! no open spark!

 

[Trent]

Re: Dropping a car engine into my boat?!

Auto/Marine

 

[mjestey2000]

Re: Dropping a car engine into my boat?!

Rodger that! Thanks for the info!

 

[coupedeville]

Re: Dropping a car engine into my boat?!

It's not that it can't be done, but to do it right , that's the trick. The engines themselves are basically the same - don't kid yourself that there aren't a lot of boats with car motors zooming about - it the details such as fuel, electrical systems, etc., that are different.

 

[DJ]

Re: Dropping a car engine into my boat?!

Novice,<br /><br />There are some things to consider besides the "hang on" parts.<br /><br />1. Automotive engines that are engineered for marine use have different horsepower/torque curves. The marine engine is under constant max. load. Unlike the auto. applications which can-coast. This characteristic is usually obtained through different cam timing.<br /><br />2. Marine engines (subjected to raw water cooling) typically have components in the cooling system that are corrosion resistant. Those components include: water pump, cast (freeze plugs) gasket materials.<br /><br />Can you rebuild an automotive engine to marine standards-absolutely.<br /><br />Hope this helps.

 

[wheels4]

Re: Dropping a car engine into my boat?!

All hard parts are the same.Pistons,rods,heads,block,and yes even the nuts and bolts.Just do it I did with great results.Remember dont believe everything you read.305 sbc 21ft. great hole shot runs strong at 4200.Good Luck.

 

[morsning]

Re: Dropping a car engine into my boat?!

Marine engines differ from automotive engines in a few important respects:<br /><br />1. Marine engines are better protected against corrosion. This includes materials in details as water pump, bolts and freezeplugs as well as avoiding aluminum manifolds. This problem can be avoided with a closed cooling system.<br /><br />2. The marine engine runs in a closed compartment while the automotive engine will run well vented. So the marine engine is equipped with special electric assesories with spark arresters; ignition, alternator, start motor. Best solved by taking these parts from an old marine installation.<br /><br />3. The marine engine will have a different cam to optimize torque for marine use. You can consider ignoring this if you think you will have enough power with the new installation. Or you can replace the cam which will bring with it additional parts and costs.<br /><br />The impeller in the outdrive should supply the heat exchanger just fine. The water pump in the engine will provide flow for the closed system. The carburettor could be slightly different in terms of choke etc but I think this is not very important. You do not need an air filter at sea, a "flame arrester" will do.<br /><br />There is a book (available at amazon) that touches on this subject. "Small block Chevy marine performance", by Dennis Moore.

 

[charleswmoore]

Re: Dropping a car engine into my boat?!

Just a Thought, I have sorta done this with my 1979 280 volvo penta. I say sorta because short of the block most every other component was hand picked. In my application I converted a Chev 350<br />to roughly a 383. If you are not set up for a big block already then this may be a good resolution.<br />The 400 crank adds a lot to the bottom end and when cammed properly it idles smooth as silk. To do this find a quaulity block. You have some grinding to do to allow the extra swing of the crank to clear. When you get ready to carry it <br />to a machine shop they will want the crank from a 400,rods,pistons,flywheel,harmonic balancer. With these components the machine shop will balance the motor by removing metal by drilling partial holes in strategic locations. When done well worth the expense (You'll be amazed) Also like previos posts indicated other parts like cam etc are special for the marine enviroment. A few things to keep in mind if you are not going to go internal of the block but looking for an inexspensive alternative. 1) Casting Plugs or referred as Freeze plugs, Change to brass. 2) Water Pump motor mounted change to marine 3)Fuel Pump change to marine (By design failure of primary seal only allows fuel to go up hose to <br />intake not the bilge) 4) You indicated EFI instead of carb. I trust you'll order aftermarket for marine use? If this gets to pricey then be careful to use a marine carb. (The float overflows route inside and not outside to your bilge) 5) Don't even consider an automotive starter, been there tryed that, it isn't worth the grief nor is it safe. (It won't hold up if engine sits low in boat) 6) Alternator I have mixed feelings in regards to but if you are insistent on using an automotive Delco Remy you will need to install either a self excite kit or use a 756 lamp to the indicator port or it will take high rpm to start charging and may fall out of charge at low RPM. 7) Distributor I'd go with HEI and make sure it comes from a 350. This is an easy alternative to points and it is simple and very reliable and very easy to service. All in one just apply D.C. and the rest is majic. 8) If you elect to be raw water cooled you must pull the heads and replace head gaskets. Automotive are steel lined and the water ports will rust out before your first season is up. 9) Before you set engine in boat consider how you are going to drain oil durring oil changes. Marine the Dip stick tube goes all the way down. If this isn't your case and you have plenty of room then no big deal but I would run me a hose off drain plug first to allow pumping. 10) I trust you will use a later model motor with hardenned valve seats??<br />11) Make sure valve covers are baffled because crankcase will need to be vented to carb backfire arrester and rarely have I seen a PCV valve in marine. 12) I am not sure your application but some stern drives require you to stutter the motor for gear shifting or (should I say gear grinding if you don't) so this will have to be addressed prior to choosing ignition!!!!! <br />Volvo didn't have this issue with a cone clutch but most others do! I don't know what Ive missed but as you can see people in the industry just won't do this because it becomes a liability that they don't need . They get blamed for so much already, granted some they deserve but most they don't. Also be careful because if an insurance company can blame you these days for negligence<br />you may be paying for a claim that extends to an entire boat house not just your own and your friends boat parked next to yours is most likely worth more than your first born? Good Luck