so can you use an automobile engine in a boat, or not?

[treehugger165]

My auto mechanic friends say no, but the marine Mech says yes. I got a brand new jasper Chevy 350 sitting in my garage, and since none of them can get the current powerplant running, that is in my boat, I would like to pop that 350 in.

 

[Don S]

Re: so can you use an automobile engine in a boat, or not?

Can you use a straight automotive engine, yes.
Should you, No.

Back to your old engine they can't get running.
If it has good compression, then the chances of it not starting with your NEW engine are very high.

 

[treehugger165]

Re: so can you use an automobile engine in a boat, or not?

Can u possibly post me a link to some of the issues reguarding that, I can't search this forum with my browser for some reason. It is really frustrating, I hate asking questions that have already been askswered...

 

[Bondo]

Re: so can you use an automobile engine in a boat, or not?

Ayuh,... It's easier if you just Tell Us what's Wrong...

 

[180shabah]

Re: so can you use an automobile engine in a boat, or not?

Have these friends given you any thought on what the problem "really" is?

 

[zbnutcase]

Re: so can you use an automobile engine in a boat, or not?

I think you need a new marine mechanic.

 

[Alpheus]

Re: so can you use an automobile engine in a boat, or not?

I have seen this argument almost break out into a fist fight.

One guy said that the SBC blocks are totally different and that He used to buy old boat blocks just because the blocks were thicker and would not over heat as much and that the crankshafts were 10x stronger than stock car SBC.

And the other guy was telling him thats 100% not true. Well the guy at the top heard all of this from his father and would not budge. Its hard hearing that sometimes info passed down from father to son is just plain wrong...

For example the infamous argument over Freeze plugs...

 

[180shabah]

Re: so can you use an automobile engine in a boat, or not?

For example the infamous argument over Freeze plugs...

...they wotk better in engines running full synthetic oil...

 

[HT32BSX115]

Re: so can you use an automobile engine in a boat, or not?

...they wotk better in engines running full synthetic oil...

Yeah it's right up there with "My Mercedes Mechanic says I MUST use this special Secret Sauce fuel and oil additive or my Mercedes won't last long"

 

[xeddog]

Re: so can you use an automobile engine in a boat, or not?

I am not an expert on this by any means, but from everything I have read and heard it isn't a good idea. There are longevity/durability issues with freeze plugs, head gaskets, etc. There are performance issues with cam profiles and distributor curves. Probably several other things that should be mentioned too. But one thing is almost certain. If you have any non-marine parts or other parts that are not CG approved, don't even think about trying to make any insurance claims. Your insurance company will most likely bolt on you faster than you can blink.

Wayne

 

[dubs283]

Re: so can you use an automobile engine in a boat, or not?

what in the flying heck is a "freeze" plug??

 

[Alpheus]

Re: so can you use an automobile engine in a boat, or not?

freeze plugs, head gaskets, etc. There are performance issues with cam profiles and distributor curves.

Core plugs = Brass

Cam = Truck or RV

Thats about it when it comes to the short block...

 

[fossill]

Re: so can you use an automobile engine in a boat, or not?

Since marine engines of the GM variety are spec'd to run anywhere between 4400 up to the 5200 rpm gamit, I don't quite understand the RV cam bit. From my days as a car/truck mechanic, RV type cams were designed to produce most efficient power between the 1500 to 2700 rpm range if I remember right. Seems if a boat engine is spinning over 4400 rpm plus, it's outside the power band of an RV cam. I would figure that a cam profile out of a stock performance/sports car would be more in line of what would be desired to get the hp/torque out of that rpm range. I'd be curious to see the cam specs out of a Merc engine compared to a stock GM cam profile. Stock performance cams are still mild in the overlap department, so water ingestion shouldn't be an issue there I would think either. As mentioned, I'm no expert, but it has me curious. It wouldn't surprise me that there are no cam differences between a stock GM automotive block and a GM marine block.

 

[skargo]

Re: so can you use an automobile engine in a boat, or not?

Ahhh, this question is on par with "can I use the search function to find out the answer to a question that has been hashed out repeatedly, or not?"

 

[Niedhogg]

Re: so can you use an automobile engine in a boat, or not?

Well I, for one, have noticed that my marine ford 302 is a much prettier light blue than the motor I pulled from a 75 Maverick I got to replace it with...

 

[Niedhogg]

Re: so can you use an automobile engine in a boat, or not?

WOW! Now that was random! It's no wonder that a guy just looking for answers to what the difference is between a marine block, and an automotive block, can't find find anything!

It seems the administraters like to move the threads to some random topic like, PROP QUESTIONS????

 

[BoomerSooner]

Re: so can you use an automobile engine in a boat, or not?

I worked at Mercruiser in Stillwater, Oklahoma. The blocks come preassembled from Chevrolet with block, cams, heads, pistons, etc. All the other parts are marine parts made for the harsher environment of a marine application. All the engines are treated as if they will be in a saltwater environment. They are not car engines. No car engines in boats.

 

[QC]

Re: so can you use an automobile engine in a boat, or not?

Stock performance cams are still mild in the overlap department, so water ingestion shouldn't be an issue there I would think either.

The cam issue is primarily about reversion (ingestion) . . .

It seems the administraters like to move the threads to some random topic like, PROP QUESTIONS????

Well, Admin doesn't move anything, and not sure why this ended up here except that it has been beaten to death over the years.

Many a road racer has come here explaining how to properly build a performance engine and then came back asking about cam changes With that said, there are a couple of really good SBC guys here that have pushed the envelope right to the edge with very good results . . . Spend some time searching for 5.7 camshaft, 350 camshaft, reversion, ingestion etc in the I/O section. I'm going to leave this here out of respect for whoever moved it.

 

[180shabah]

Re: so can you use an automobile engine in a boat, or not?

It wouldn't surprise me that there are no cam differences between a stock GM automotive block and a GM marine block.

Prepare to be NOT suprised. That high performance marine grind cam is straight off the truck parts shelf. Merc and VP's nasty little secret

 

[79Merc80]

Re: so can you use an automobile engine in a boat, or not?

Also, take this to heart.

In an auto, once you get to speed (20, 50, doesn't matter) it takes a lot less to keep you at that speed and it did to get you there.

In a boat, that's not the case. The engine would be under a constant load from the friction of the water and the weight of the boat trying to get back to a displacement speed.

Another way to look at it. Get your car up to 40mph, then kick it into neutral. See how long it takes to come to 5 MPH (No Wake Speed)

Now do that in a boat. It takes a LOT more hp to keep a baot at speed than a car and automotive engines are not built to take that, marine engines are.

Hope this helps.

Craig