carb help

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: carb help

You can get by with using aluminum in fresh water, but it is still not recommended. If you use aluminum parts in salt water you need a closed cooling system. It's a type of electrolysis corrosion I believe.

Mercruiser used aluminum intakes on the 454's, without fresh water cooling.
I've heard of galvanic corrosion an I've heard of electrolysis. What is electrolysis corrosion?
 

rs2k

Chief Petty Officer
Joined
Aug 2, 2008
Messages
486
Re: carb help

It's the same thing:

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially when in electrical contact with a different type of metal and both metals are immersed in an electrolyte. Conversely, a galvanic reaction is exploited in primary batteries to generate a voltage. A common example is the carbon-zinc cell where the zinc corrodes preferentially to produce a current. The lemon battery is another simple example of how dissimilar metals react to produce an electric current.

It's either called electrolysis or galvanic corrosion, I mislabeled it as electrolysis corrosion.



Aluminum can be used, but you need to coat the water passages or use a fresh water cooling system. I've heard of people coating the waterways with a thinned down mixture of JB Weld and alcohol before.
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: carb help

It's the same thing:

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially when in electrical contact with a different type of metal and both metals are immersed in an electrolyte. Conversely, a galvanic reaction is exploited in primary batteries to generate a voltage. A common example is the carbon-zinc cell where the zinc corrodes preferentially to produce a current. The lemon battery is another simple example of how dissimilar metals react to produce an electric current.

It's either called electrolysis or galvanic corrosion, I mislabeled it as electrolysis corrosion.



Aluminum can be used, but you need to coat the water passages or use a fresh water cooling system. I've heard of people coating the waterways with a thinned down mixture of JB Weld and alcohol before.

Hardly the same. Question. If both processes are the same, why two different names?

Galvanic Corrosion
Galvanic corrosion occurs when two dissimilar metals form a natural battery when placed in contact with each other while immersed in an electrolyte. Seawater is a perfect electrolyte for metals. Metals vary in their reaction to being part of this natural battery. Metals that are more active are anodes or less noble. In a galvanic cell a less noble metal, like zinc, will dissolve sooner a more noble metal like brass. Prevention includes proper choices for metals used in vessel construction, use of protective paints and sacrificial anodes.

Electrolysis
Electrolysis is also the corrosion of dissimilar metals, but a different process causes it. A difference in the direct potential current that exists between two dissimilar metals is the reason for the problem. This is a stray current or circuit that is not following an anticipated path. Improper wiring, poor choices in building materials, or defective electrical appliances can cause it. Introduced currents will flow by the path of least resistance. Stray current can also cause Electric Shock Drowning.

Electrolysis is much more destructive to boats than galvanic corrosion. You can reduce electrolysis with these ideas:

?Avoid the use of common automotive battery chargers on your boat. These chargers use an auto transformer in which the primary and secondary windings are electrically connected. Marine battery chargers use an isolation transformer. An isolation transformer has separate windings and does not allow current to pass into the vessel from the utility connection
?Vessels using a positive ground electrical system should avoid mooring next to one with a negative ground system
?Check the connections to any two bilge pumps that are electrically connected. Ensure that each pump shares the same positive and ground connection. If one pump is grounded to the frame and the second is not, a stray current will be introduced
?Electric welders can introduce current into salt water due to frayed or damaged connectors. If welding is required on a vessel, it is better if the welder is mounted on the boat being welded
?Check your vessel for reversed polarity
?Check to see if any severe corrosion is present near telephone connections. Telephone service voltage can introduce 48 volts of current into the water
?Install sacrificial zincs on your boat and properly maintain them
?Keep a layer of quality bottom paint applied to all hull surfaces in contact with the water
?Tilting your outboard motor out of the water may completely eliminate corrosion


"JB Weld and alcohol"
Be careful what you listen to. This is as good as the "magnetizing water".
 

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: carb help

thanks for all the input, how could i find out if it is a 98 w/ vortec, it can run with my brothers baja and he has the mpi w/ vortec heads. maybe i am wrong about the year. just doesnt seem like it only has 210hp

Count the number of bolts on the intake which mount it to the heads. 12 bolts (6 per side) and it is standard heads, 8 bolts (4 per side) and it is vortec heads.

PS: I had a 210HP 5.7L that I have changed to vortec heads, 4brl Q-jet, and stock marine roller cam. The 70HP increase only bought 5-6mph wot top speed.
 

greenwell001

Petty Officer 2nd Class
Joined
Aug 5, 2009
Messages
121
Re: carb help

John S

Thanks for the advice, i have been told it is not worth putting a lot of money on a small block if your wanting more than 4-5mph because that is about all you can get. How about acceleration and raw power? I am wanting to change to your setup after the season is over. Was it worh the money?
 

wca_tim

Lieutenant Commander
Joined
May 28, 2007
Messages
1,708
Re: carb help

couple of things...

corrosion with aluminum is a potential issue if you run in saltwater, then the heads, manifold, etc... needs to be hard anodized if you want it to last - it's what imco does to their aluminum exhaust manifolds that are run in open ocean racing apps, it's what some of the cylinder head manufatures do to their heads for offshore racing as well. it renders the surface non conductive (no galvanic corrosion here!) AND changes the composition of the metal at the surface to make it nearly impervious to salt water corrosion. It's also MUCH harder than aluminum. any paint like or solvent -based coating you're going to apply to the interior water jackets is a waste of time and energy, and when it flakes off may cause problems worse than the corrosion.

IF you're going to make changes to an engine or build one, cylinder head choice is probably by far the most important limiting component in the power you can make and the running characteristics for the engine.

5-6 mph on top end is huge! and the seat of pants that came with it probably very noticable. if you want 20 mph gains, be prepared to shell out bucks on engine replacement or buy a different boat.

a well built small block - especially one that's stroked like a 383 or 406 - can be made very reliable and make a good bit more horsepower and torque than a stock 454. for somewhere in the 5-7k range you can have a stroker built that will reliably make well over 400 hp and on the order of 500 ft pounds of torque and do so without any loss in usability or longevity. The weight difference is substantial as well. the small block chevy engine is soooo popular for hot rod aplication that a huge variety of off the shelf parts makes building one very economical.

I like the edelbrock marine carbs. on a close to stock engine, it's a drop on and go. they are a performance carb, and a very economical choice, but not the end word in terms of making power.

just my two cents
 
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