cylinder head repair

[MARNEN]

My cylinder head is blowing between the cylinder and the water jacket. Any one had one repaired/welded ?
Where to go for a replacement ?

 

[Avocet]

I had that this winter! What's the engine? I was lucky enough (through some kind member of this very forum, in fact!) to find a second hand one on eBay. I looked at trying to sleeve my old one, but the port isn't straight, it curves and the wall thickness wasn't sufficient to bore a straight line through it. I could relatively easily get to both sides of the hole and if I hadn't been able to find the other head, I was going to try a small nut and bolt with big washers either side and some exhaust paste under the washers. The hole wasn't accessible enough to sure of being able to get a good braze or weld on the cast iron.

 

[Champagne Murphy]

My cylinder head is blowing between the cylinder and the water jacket. Any one had one repaired/welded ?
Where to go for a replacement ?

How often has it happened? Are you sure it doesn't just need a new gasket or a skim?

 

[GrahamM376]

Just where is the problem? Quite normal to have a cylinder head skimmed if the damage is within the area covered by the head gasket. Suggest you take it to a motor trade engine reconditioner if the problem is elsewhere, heads can often be repaired.

 

[Bilgediver]

My cylinder head is blowing between the cylinder and the water jacket. Any one had one repaired/welded ?
Where to go for a replacement ?

We need more info.Where is the leakage/hole ? In the had casting or at the head gasket? If at the head gasket Is the leakage spread over a wide area or just a narrow gas cut less than 1mm wide.

 

[MARNEN]

Thanks for the interest. The engine is a yanmar 2gm20. We thought it was a blown head gasket when we took it apart. Put a new one on and it blew in the same place. As far as I know at the moment the underside of the head has a slight sinking in it between the a water jacket hole and a piston bore. Doesn't look cracked. My thinking is to maybe get a blob of weld in the sinking and grind it flush with the rest of the flat surface.

 

[Tranona]

As already suggested take it to a local engine specialist who will advise what can be done. You can't take too much off as that will affect the compression ratio, but a good shop will know what to do. The Yanmar workshop manual has the details of minimum and maximum clearance between the top of the piston and head.

 

[Topcat47]

Are you sure it's the head? Get a nice bit of 10mm float glass from your friendly neighbourhood glass merchant and a small tin of "engineer's blue". Smear the "blue" on the head and wipe it on the glass. If there's any blue left on the head when you take it off, that's the low point(s). Clean off the glass. Using photographer's spray mount, stick some 400/600 grit emery paper tenth other side of the glass and using a drop or two of 3-in-one as lubricant, slide the head around on the emery paper. once the blue spots have vanished, repeat the process. until no blue remains on the head when wiped on the glass.

This doesn't work if the head's cracked but you might get a blue line at the crack site. Dye penetrant is a better indicator of a crack though. and it's relatively expensive.

This also doesn't work if it's the top surface of the cylinder that's damaged.

There's a guy in Glasgow who welded up a friend's head that was damaged by the dreaded 1GM10 elbow failure so there are engineers out there capable of more significant work.

 

[TQA]

You definitely do not want a weld in that situation.

All that is required is that the head be surface ground. A standard job for any engine repair machine shop. They will take off the minimum and it is unusual for that to create compression problems.

But see what the manufacturers say first RTFM.