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Author Topic: 390 motor w/rust in cylinders  (Read 1279 times)


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390 motor w/rust in cylinders
« on: February 05, 2007, 02:52:34 PM »
You may have read my post on 1/26 about "lots of water in the oil pan."  Im trying to bring this motor back to life after it has sat for 25 years.  Im not too familiar with the inner workings of this motor, so I thought Id run this by the group.

With the plugs out I can see that the electrodes on the spark plugs in cylinder #6 & #7 are really rusty.  Both pistons are at the top of each cylinder.  Both cylinders are also fouled up with what looks like white carbon deposits with a little rusty color mixed in.  When I removed the spark plug from cylinder #6, the cylinder looked completely filled up with this debris.  Its a gritty mix.  I am vacuuming this stuff out by inserting a small flexible hose into each cylinder and agitating it around.

Given the firing order for this motor (18436572), and the fact that both #6 & #7 pistons are at the top, am I guessing correctly that the reason these two cylinders could be in such bad shape is because #6 has the exhaust valve open and #7 has its intake valve open?  With an open valve, moisture would easily get into the cylinders, whether its coming from the intake or exhaust.  And the exhaust pipes had long ago rusted away from the exhaust manifolds, so moisture had easy access to all the exhaust valves.

Im trying to solve each puzzle as I find them, and hopefully learn something along the way.  Any thoughts on this matter would be appreciated.  Thanks.

Bruce Reynolds # 18992

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Re: 390 motor w/rust in cylinders
« Reply #1 on: February 05, 2007, 05:50:52 PM »
Gday Mike,

Seeing what you see, I, personally, wouldnt be trying to start it up at all.

If I ever found something like what you describe, I would be stripping it down, or at the least, removing the cylinder heads and go from there.

Sounds like the engine is ripe for a total rebuild, including boring out, larger pistons, plus whatever else has been damaged by water, and or age.

The Tassie Devil(le),
60 CDV


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