350 vs LS1 vs LQ4

[RangerTurbo]

This isn't about a car engine, and I know next to nothing about Chevy motors, but I figured the Chevy guy's here would be able to answer my questions.

 

My buddy has a boat with a carbed 350 that has coolant in the oil. He's debating fixing this one or swapping in a JY motor.

 

Do the LS1's and 350's by chance have the same exhaust bolt patterns? He's thinking about swapping one in if we can get away with using the stock water cooled exhaust manifolds in the boat.

 

 

Horsepower TV did a build up of a JY LQ4 engine. I thought they stated the LQ4's were the iron LS1's instead of aluminum. Research tells us though that the LQ4's are just bored or stroked 5.3' Vortecs. Can anyone shed light on that one too?

[gillbot]

No, they won't swap.

[Cordell]

The vortec 4.8 and 5.3 share teh same block and are in the LS family of engines, however the LQ4 and LQ9 are 6.0 and are a little different. All of these engines share teh same external deminsions, and basic design with the LS1. An older 350 engine shares almost nothing with the newer engines, so no it wouldn't be a very cheap swap.

[Guest Removed]

put another 350 marine motor in it.

 

standard 350 blocks are different from the boat motors.

[rl]

standard 350 blocks are different from the boat motors.

 

Whats different? As far as I knew it was SS headgaskets and SS valves.

[Wonderboy]

There is no difference, they are all equally worthless. And they will all work equally as well to anchor down your boat. :p

[Sam1647545489]

Whats different? As far as I knew it was SS headgaskets and SS valves.

 

I thought it was this as well.

[Cordell]

There is no difference, they are all equally worthless. And they will all work equally as well to anchor down your boat. :p

 

About like an SR20 motor or a rotary, stop thread shitting. :asshole:

[Wonderboy]

About like an SR20 motor or a rotary, stop thread shitting. :asshole:

 

Agreed.

[Guest Removed]

Whats different? As far as I knew it was SS headgaskets and SS valves.

Way more then just those 2 things. cams, carbs pumps and so on

I had some this info , cause i did a write up on it in high school. but for now im coping and pasting the info here. just for the sake of a argument. now marine engine's will work great in a car, when the cam is changed.

 

A car engine is a LIMITED duty engine and a marine engine is a continuous duty engine

There are many differences between a limited duty engine and a continuous duty one. As an example , it is necessary to understand the difference between an SAE work test and a standard BRAKE test. Both tests are performed on the same device called an engine brake or engine dynamometer. Essentially the engine is run up against a variable load. This load device is mounted in bearings so it can rotate, but it is prevented from rotating by a lever which is attached to a scale. This scale will read out in ft. lbs.. So at any engine speed the maximum torque can be read. Because torque is one component of horsepower and speed being the other, horsepower can be calculated as well as fuel consumption, brake mean effective pressure and a number of other items. The important thing is the test program. A BRAKE test is where the engine is warmed to normal operating temperatures and then run up to maximum power and that's the end of the test. An SAE test, on the other hand is run up against the load for a sustained period (maybe 4 hours) until the maximum power is reached that DOES NOT exceed acceptable manufacturers operating parameters like oil, water, exhaust and head temperatures and pressures. In this example mentioned the Chev. 350. This engine will brake somewhere around 220 to 280 HP depending on state of tune. The maximum SAE rating of this engine is 55 HP.

 

I suggest that if you were flying on a plane, or on an ocean cruise ship, you would want the engines tested under an SAE test program. The differences in design and build are many. Intelligently, you have to factor the type of usage you need from the engine and then modify the automotive engine accordingly. The greater the durability, the greater the cost. Nothing is for free and when a marinized automotive engine costs are comparable to the standard automotive variety, you must question it's durability.

 

Valve seats are a big issue (Stellite seats),Brass freeze plugs , and the water flow is completely different aswell.Change the Alternator, Starter and Distributor to their respective Marine Versions. The carb, fuel pump and all are completely different. Even the water pump is SS.

 

Raw water cooling systems draw water from outside the boat (seawater or lake water). Water is pumped from the source to the engine block then the engine circulation pump forces the raw water thru the engine block and the water is expelled thru the exhaust. Raw water cooling systems are relatively simple and the standard cooling system on most Marine Engines. The raw water pump in most cases is inside the outdrive. On larger engines and inboard engines the raw water pump is located inside the boat and is driven by a v-belt or directly off of the crankshaft. There are hidden dangers that can accumulate over time causing you to spend big Dollars on repairs. The danger is using salt water as a coolant in your engine. Salt water can be highly corrosive. Running salt water through your engine block and exhaust manifolds will lead to destructive corrosion that is unseen until your engine or exhaust manifolds fail.

 

Generally speaking, marine engines cooled with raw water, especially ones that use salt water, have a shorter life span than marine engines cooled with a closed cooling system.

 

 

The biggest difference is the cylinder block. Marine engines are based on heavier-duty truck blocks, with four-bolt main bearing support of the crankshaft instead of just two. Keep in mind a car only uses about 15 of its one or 200 horsepower to sustain a speed of 55 mph. Conversely, a boat is always under load. Its marine cycle can be compared to hitching a 10,000 pound boat and trailer on the bumper of a car and trying to climb the Rocky Mountains at 80 mph.

 

Besides duty cycle there are other important differences. A marine engine’s core plugs are corrosion resistant bronze. The camshaft is ground to different specifications, most often to maximize low end torque. Also, the camshaft profile is different. Valve overlap (the time when both intake and exhaust valve are open) is shortened to minimize the chance of water being sucked out of the exhaust and into the combustion chamber. Gaskets are premium quality for better sealing and corrosion resistance.

 

Most important of all are the starter, alternator and distributor. All three components are fitted with special screens that quench internal sparks that might otherwise vent into the atmosphere and light-off gasoline fumes present in the engine compartment.

 

For the same reason, a marine carburetor bowl vents overflow to its throat, instead of to the atmosphere. Marine carburetors meet USCG specifications for safety.

The bottom line, an unmodified automotive engine is totally inappropriate for a boat motor. Its torque curve won’t meet the needs of a boat, its light-duty components won’t long survive the rigors of marine usage, and you risk blowing yourself out of the water. You decide.

 

There is tons of great info here http://www.boatdesign.net/forums/diy-marinizing/auto-engine-marinization-650.html now its a long ass read, but well worth it in the long run. and this and some other sites is where this info has came from.

[RangerTurbo]

Wow... more info than I could have asked for , thanks Gearhead.

 

The more we googled, the more he accepted that he'll either be fixing this one or buying another block and swapping all the goods into it. We might get lucky and its just a blown head gasket, or might not be so lucky with a cracked head or block. He just got the engine out of the boat so haven't had time to strip it apart yet, and he deploys to Iraq next month so this might be a year before we get to it anyhow.

 

 

 

SO, assuming its just a bad head gasket or relatively easy fix, what would be the danger of making this a 383 stroker, but using the marine cam? The stock 260 HP is nice,... but more HP/TQ can't be a bad thing right?

[Bigbird]

Agreed.

 

LOLQR25

 

 

 

Ah who am I kidding...I miss my Spec

[Clifford Automotive]

 

 

 

SO, assuming its just a bad head gasket or relatively easy fix, what would be the danger of making this a 383 stroker, but using the marine cam? The stock 260 HP is nice,... but more HP/TQ can't be a bad thing right?

 

There is no danger. Ive put more 383's in boats then anything else. Whats the concern? Ive taken plenty of engines out of cars and used them for starting ground for a boat engine. Just make sure you use marine grade material. Oh and my carb bleeds to the atmosphere not back to itself.

[Guest Removed]

There is no danger. Ive put more 383's in boats then anything else. Whats the concern? Ive taken plenty of engines out of cars and used them for starting ground for a boat engine. Just make sure you use marine grade material. Oh and my carb bleeds to the atmosphere not back to itself.

 

so your bowl vents go up instead of turn down into the main body?

[RangerTurbo]

There is no danger. Ive put more 383's in boats then anything else. Whats the concern? Ive taken plenty of engines out of cars and used them for starting ground for a boat engine. Just make sure you use marine grade material. Oh and my carb bleeds to the atmosphere not back to itself.

 

My only concern was timing events with the stroker. I know there shouldn't be a problem... but the quirks of having a marine grade engine made me question it is all.