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truck to marine???

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reinell192

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I have a couple 350 v8 and i just froze mine in half- outside air was -10 f and i did not keep it warm enough---can i swap one 350 for the other?? they are both z71 chevy motors
 
In one word, Yes, but with a couple of precautions.

Use all the original Accessories, and replace the Welsh Plugs with Brass or Stainless Steel.

But, before you toss out the frozen one, remove the internals as they might come in handy in the future, especially the Camshaft, as if it was a Marine engine, it will be different to the Truck one.

But, hang on, didn't you say that both engines were identical Z71's?

Bruce.
 
no need to change cams they are almost the same, maybe the same.

But it is a good idea to store it.

You boat in fresh water then the gaskets don't matter. Saltwater you might want to change out to marine gasket.

Might already have brass casting plugs.

You will need the marine starter, alt, and dist.

Engine mounted water pump won't matter if you boat is fresh water, but salt you need the marine brass vane one.

Keep us posted.
 
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reinell192 said:
I have a couple 350 v8 and i just froze mine in half- outside air was -10 f and i did not keep it warm enough---can i swap one 350 for the other?? they are both z71 chevy motors
Click to expand...

Why...didnt you adequately drain the block? I put a Shop Vac in reverse attached to the rad hose. It works Great !! Even blew out the rusty water that was trapped.
 
automotive engines dont typically have forged pistons. a marine engine is designed to turn 4500+ rpms and automotive engines are designed to turn 2000 or less rpms on a constant basis. if you use an automotive engine in your boat, stay close to the bank so when it comes apart, you can get to land.
 
Disagree. Truck motor started out same as a marine engine, same assembly line. One went to the marine guy who threw on the externals.

Ask me the 91' as the same gaskets as the marine. Look on the block see anything stamped marine ?

Nope.
 
I would have thought that the Truck Motor would have had a Camshaft designed for low end torque, and not screaming it's head off?

One think I did find when I converted a 327 Mercruiser V8 to road use was the Sump was Copper, and the Carby was Copper Plated with Stainless steel Shafts, and I think Brass Butterflies, and the Water Pump has a Stainless Steel shaft. But then, they would be classed as "Externals"?

Bruce.
 
what's a z71 motor? isn't that a truck? If they're both in trucks why does the thread title say truck to marine?
lost me
 
the change to 1 pc rear main for V6 and V8 was 1987
inline 4's changed in 1990

but now that I think of it, I was wrong regardless. I should have said not doable if he has a stringer drive (1985 or earlier). Any Cobra can be mated to a newer engine, just requires buying a new coupler.
 
"SOME DIFFERENCES BETWEEN AUTOMOTIVE & MARINE ENGINES

For those of us in the marine industry, a common occurrence is to be questioned by customers about auto vs. marine parts. A common scenario is to have a customer ask for a replacement part for his boat. The part in question is a starter for a 350 cu.in. GM block. You give the customer a price, and he looks at you with a blank look on his face. He, then states (very angrily) "I can get one at the local auto retailer for $29.95".

In the marine industry, this little scenario occurs all the time. Many boaters are unaware of the difference between an automotive and a marine engine and their respective accessories. The most notable differences include the exhaust systems, the cooling systems, the electrical systems, and the fuel systems. Additionally, items such as heads and cams are usually different. For the purpose of this article, we will only be hitting the highlights on select systems.

In regard to the cooling systems, one of the major differences is found in the water-circulating pump. This is especially noticable when you have a raw water cooled engine. Unlike their automotive counterpart, a marine pump works in an open cooling system. This type of system is extremely corrosive to the pump. Therefore, the pump must be altered for longevity. A marine pump has a special ceramic seal, stainless steel backing plate, and a bronze impeller to resist corrosion. An automotive style pump, with its stamped steel impeller, would fail due to corrosion in a short time.

The electrical systems in a marine application are also extremely specialized. In an automobile, any gasoline vapors that accumulate will readily dissipate through the bottom of the engine compartment. However, a boat with its sealed engine compartment, does not have that luxury. Therefore, any spark could literally cause a boat to explode. All electrical components in a boat are either completely sealed or specially vented to prevent such a catastrophe. This includes the starter, alternator, distributor, and many other engine electrical components.

Carburetors typically have what is known in the industry as J type fuel bowls. These allow for the extreme vibration, pitching and yawl experienced on boats. This allows fuel to be drawn in exteme conditions and keeps fuel from being ejected from the carburetor barrels.

Heads and cams are set up for a completly different torque curve. A marine engine must develop most of its torque on the low end of throttle range. This allows for the ability to use a single gear transmition system. Think of it this way:
You get in your car
Start it up
Drive to the highway
Put your foot to the floor and hold it there for an hour
Its a little different, well for most of us.

Although we have only briefly touched on some of the differences between an automotive and marine application; hopefully, it will serve to remind us that there is a difference, and that the reasons for these differences need to be shared with our customers and friends in the boating community. Hopefully, when shared, this information can eliminate some of the "blank stares" in regards to parts, and maybe prevent some dangerious situations."

http://www.ehow.com/facts_5868385_difference-engines-passenger-car-engines_.html
 
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J 1171 is stamped on marine starters, alternators, dist. because they are marine rated. Why are they different?

Because as stated in the above article, fuel vapors in a confined area, and spark are not a good combination. Marine rated starters, and alternators, dist. have screens not found in auto components. Thusly the more expensive they become.

How about the all important manual fuel pump and carb. ?

Again touched upon in the above article but not explained.

A auto manual fuel pump " not found on modern autos, but are found on boats " would vent fuel to the pavement if the diaphragm ruptured in the fuel pump.

In marine applications there is a clear return line, to the carb... see fuel in the line the diaphragm ruptured. The boat would not run correctly or not run at all.

The carb... would have the hole if a marine one for the line. Not found in a auto carb.

For the purpose of this post allow me to use a Rochester 2cg carb as a example. Really my favorite carb.. 4 barrel or 2 barrel, in my humble opinion, bullet proof.

The only difference is the return hole drilled for the return line.

Mecarb, is a Rochester one screw design.

Omc " 2 screw design " Rochester is the same.

Remember i posted this is only a example.

Bite the bullet pay the price difference, the life you save might be your own.
 
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Well Mainly its due to being "Intrinsically Safe"!

All marine components are built to be used in hazardous locations, (explosive in th is case) reason being that gasoline and enclosed spaces is a hazard. See Coast guard image below.

So all these components the Distributor for example has modification made to prevents "spark jump" (Watch this video) and a description is at 3:25.

So to make a long story short (to late i know lol) the answer is no by Coast guard statues regarding marine components in a confined space with all electrical components.

The other mechanical difference are mainly life expectancy cam, pistons, heads and previsions for the slat. (See Mercury Explanation)

I am not saying that this is not and or has not been done.

Also here is a snipit from a OEM manual.
mercmanual.png

Coastguard.png
 
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tony edwards said:
automotive engines dont typically have forged pistons.
a marine engine is designed to turn 4500+ rpms and automotive engines are designed to turn 2000 or less rpms on a constant basis.............
Click to expand...
If that is to imply that the GM OEM Marine version does use a forged piston...., that is typically not so.
Anyone running their cruiser type marine engine at 4500+ rpm is destine for a short engine life. That rpm range is intended to be at/near a WOT RPM for a test only (gear/prop/final drive ratio/hull condition/engine tune, etc.).


I respectfully disagree with the head gasket comment. You may get a few years from the auto head gaskets if in river/lake water. Salt water.... no!
While any corrosive action is minimal in river/lake water, it still exists for a head gasket that does not use the correct material designed for raw water cooling, IMO.
If the 1991/92 head gaskets were of the correct composite (that also works for raw water), then I suppose that you'll be OK.

As for pistons...., no matter what, you're going to have the full dished pistons in the truck engine or the OEM GM marine engine.
A bad choice for Marine cruiser use, when there are better choices available! IMO.
Small boat..... you may get away with it!

GM continues to use this silly full dished piston in their Marine version SBC, and apparently can't bring themselves to use a correct piston that may cost a few dollars more!
(this is all about a offering or NOT offering a correct "quench effect" in the SBC combustion chamber)
It may not be a result of the engineers, but rather a result of the Bean Counters.
If the Bean Counters are in control, this will never happen! :mad:

.
 
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I think so.
It happens all too often where someone asks a question, looks for only the answer that they want to hear, then they're gone!
Oh well!

.
 
sorry guys but i read this just about--like always since i did start thread so NO! i haven't began work----plus it's under about a foot of snow for a week or so--I'll be reading--later--reinell192 out
 
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