Cracked Block

[Capt_Scarlet]

I have a second-hand Yanmar 2GM20 which has suffered from water in one of the bores. I needed to have a new valve-seat and new valves fitted, and was hoping that was it. I was about to put it back together, when I noticed that the block had previously been drilled and tapped with overlapping studding between the offending bore and the water jacket, with some small tracks across the repair. Not qute sure what to do now....

I could put the sod back together, and hope that a new head gasket can cope. Probably the triumph of hope over experience....

I could try to get an engine repairer to have another go at the crack repair. Is there some high-tech fix for cast iron now?

I could try to get a replacement block - I suspect this is the best but I dread to think of the cost of a new one.

Has anyone else had the same dilemma?

Thank you.

<hr width=100% size=1>

 

[vyv_cox]

I suspect that this is something of a problem. There are cast iron welding specialists, a search found<A target="_blank" HREF=http://www.castironwelding.co.uk/>this one</A> for example but the technique is quite difficult to apply. I had a cylinder head repaired about 15 years ago: it was cheaper than a new one and it held together OK after being re-done once.

<A target="_blank" HREF=http://www.tec-cast.co.uk/> This one</A> looks interesting and they talk about small engines. Might be worth talking to them. I realise that this is how your current repair has been done but maybe there's something to be gained by having it done by specialists.

<hr width=100% size=1>

 

[mtb]

It sounds like a new one is needed cos the crack or fracture could go a long way down so applying stuff just to the surface wont work.
I have used modern fillers like perma bond metal repair past on cylinder heads with great success but it was only where the corrosion had eaten away at the edges and would have quickly blown the new head gasket. This was on a diesel truck and road use, I don't think my conscience would allow this type of fix on a boat's engine if it were to go to sea.
Welding could be the only answer but metal stitching !!
cheers
Mick

<hr width=100% size=1>smile you'l be on your boat soon ;-)
<A target="_blank" HREF=http://homepage.ntlworld.com/boats/>http://homepage.ntlworld.com/boats/</A>

 

[owelly]

Are you sure it is what you think it is? A good method of repair is "metal-stitching" usually done by "Metaloc". It's where you drill a series of holes, using a jig, then hammer in a row of "stitches". The metal "stitches" come in strips that are cut to length. We use these on castings on Mirrlees engines and we have repairs that are 30 yrs old and still good. Just a thought.

<hr width=100% size=1>

 

[mtb]

Yes I know about this as it's done mainly on vintage engines and yes it works, but the high cost and the fact that it's mainly used to repair the out side of a block and not the head face re ci engines, leads me to this conclusion . hey it's just my opinion !.

cheers
Mick

<hr width=100% size=1>smile you'l be on your boat soon ;-)
<A target="_blank" HREF=http://homepage.ntlworld.com/boats/>http://homepage.ntlworld.com/boats/</A>