corrosion

LindenLongRods

Petty Officer 2nd Class
Joined
Jul 10, 2007
Messages
192
1971 18hp Evy. When I took head off I notice salt and corrosion had gotten in-between outside cylinder wall and block, situated mostly between the two cylinders. when I cleaned up a bit I notice some of cast corroded away leaving cyliner maybe 10% exposed to water channels. No damage to cylinder or shape and motor ran before. My question is how important is cast around cylinder walls and should I supply a pic to better explain? LIke I said block is not cracked, only damage appears is that some cast corroded, and no damage to piston or cylinder.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: corrosion

The cast aluminum at the very top sealing surface (head gasket area) if eaten away by corrosion will eventually allow water to enter the cylinder so of course, that's quite important. A machine shop can add aluminum to that area via the heli arc method to restore that area.

Should the aluminum be eaten away further down the water jacket/cylinder area, I would think that would create a difference of temperture in bare areas should the sleeve actually be exposed to the water flow... but how important that might be other than water might seep by into the cylinder, I don't know and will wait for someone more knowledgeable in that area to enlighten us.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: corrosion

Actually, the situation is quite common in salt water areas. As Joe said, somebody MAY be successful in welding new material in there. However, from what I've seen, results have been dissapointing. You have to go too far to get to uncontaminated metal to weld to. Try to salvage it if you can, however I really hate to say it, but that block is junk. What I really hate is when somebody will patch something like that, then sell it to some unsuspecting sucker. Happens all the time.
 

wired247

Lieutenant Commander
Joined
Oct 8, 2011
Messages
1,557
Re: corrosion

The exposed iron cylinder liner can be overcoated with a spool gun aluminum wire feed welder. You can TIG it but the spoolgun makes quick work of it. Thats the good news. The bad news is that the heat from welding may require you to bore the cylinder afterwards as the bore may distort..
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: corrosion

In total agreement with MWG..... No way to repair that crankcase.
 
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