Hairline crack in cylinder head

[heinzb]

My engine refused to start after a sail. While try anything to get the engine started again I removed the sparkplugs and discovered that there was water between the contacts. I dried the contacts several times, shut off the water supply but no luck. I ended up having to call for a tow.
I deducted that it had to be a crack in the head since I had replaced the gaskets a couple of years ago.
I removed the cylinder head and noticed that there was water on top of the valves for the fourth piston. The piston housing also had rust stains I sent the head to a machine shop for magnafluxing. They found a hairline crack on the top running from the left side around the alternator block but the block inside showed no sign of a crack or leak. I have include a couple of image showing the crack and also the condition of the exposed block.

Regarding the crack, I was wondering if anyone had any welding done to a cylinder head?
Also, what other areas of the engine could cause the water to enter the pistons?

Heinz

[ndutton]

You'll be welding on very thin, corroded metal. Please read this thread from two months ago:

http://www.moyermarineforum.com/forums/showthread.php?p=114021#post114021

What will you have if you spend the money and effort having this head welded, checked for straightness and perhaps machined as a result? A rusted head that's likely beyond its useful service life. Nope, if it were me I'd replace the head outright, do it once and do it right.

[edwardc]

Just thought I'd weigh in here with my 2 cents.

Given the location of the crack, and the fact that it was #4 with water, I speculate that you may have two separate problems.

As for the cracked head, I agree, its not worth the effort of trying to repair. I tried once and it was a giant waste of effort. I ground down a Vee along the crack, and filled it with JB Weld. Trouble was, the crack just kept extending past the end of the JB Weld and leaking again.

The water in the #4 cylinder makes me suspest that this was a case of flooding through the exhaust port. Extended cranking without a start, with the water intake open, will fill the exhaust section with water until it backs up all the way to the manifold. #4, being lowest, always gets flooded first.

After cleanup, the solution is simple. Always start the engine with the water intake closed! Open it only when the engine has actually started. I got this advice from Don himself years ago and pracctice it now every time.

[joe_db]

+1
Buy a new head and avoid this being an annual repair.