Yanmar Cylinder Head Repairs?

Ubergeekian

Ubergeekian

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Joined
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Me: Castle Douglas, SW Scotland. Boats: Kirkcudbri
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My friendly local engine reconditioner have politely returned my 1GM10 head because of a crack extending about 1/2" from the exhaust valve seat. Is this truly game over or is there any welding process which might save me?

Meanwhile, if anyone has a spare 1GM10 head, please look at my advert in the Wanted section. Or don't bother, 'cos all it says, really, is "Wanted, 1GM10 cylinder head".

Help!
 
About 35 years ago I had a VW diesel engine cylinder head repaired at Aberdeen Head Shop. It had been completely wrecked by a total engine disaster. They managed to weld it up and it worked fine afterwards. Google tells me that Head Shop now means something very different! However, Aberdeen Head Shop are still in business.
 
vyv_cox said:
About 35 years ago I had a VW diesel engine cylinder head repaired at Aberdeen Head Shop. It had been completely wrecked by a total engine disaster. They managed to weld it up and it worked fine afterwards. Google tells me that Head Shop now means something very different! However, Aberdeen Head Shop are still in business.
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Thanks Vyv. I shall pursue enquiries. A new head is £450, or £350 if I can persuade friends to bring me on from the US, so a repair could be quite economically justified.
 
Ubergeekian said:
A new head is £450, or £350 if I can persuade friends to bring me on from the US, so a repair could be quite economically justified.
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Would they be bringing it as hand luggage? Perhaps they could tell customs it's an Art Deco paperweight they picked up for a song.
 
Did the (common) repair on a Cooper S, when it cracked between the inlet and exaust valve in the cast iron head. Worked fine. As yours is an ally head (?), welding and a new seat should be effective. As a single, less problem with facing up after.
 
DownWest said:
Did the (common) repair on a Cooper S, when it cracked between the inlet and exaust valve in the cast iron head. Worked fine. As yours is an ally head (?), welding and a new seat should be effective. As a single, less problem with facing up after.
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It's a cast iron head, alas, which makes things a bit trickier ...
 
Ah, going back to the Cooper S, we had the the head welded by a firm in Norwich then re-ground the valve seats ( including the welded bits). In your case, I would still have a seat fitted after the weld.It is only one. Belt and braces?'.

History: The S was designed as a race engine and had the biggest valves they could fit in the combustion chamber. Essentually to remain legal when tuned up for the track as a production car. This left very little metal between the valve passages. A little overheat could crack the wall. This was on a Downton tuned S so a bit more prone to trouble.
Of course the basic design was too old to cover all bases. Cooling was one of them.
 
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Ubergeekian said:
Hold baggage. And they've said yes, so I'm just waiting to hear back from the cast iron welding companies which nice Mr Google found for me.
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Pointless, do not heed the so called experts suggesting repair is either feasable or practical.

People who should know better have forgotten that engine is direct cooled, salts will have well and truly attacked the iron.

Scap off engine and start again I am afraid.
 
I would have thought that the the engine reconditioners would know best and if they have given it back then it's game over.
 
Spyro said:
I would have thought that the the engine reconditioners would know best and if they have given it back then it's game over.
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The people I went to don't do cast iron welding at all, so it seems worth asking people who do. I suspect the answer will still be "no" or at least "not economically". A new head will cost me £350-ish: the old one will need welding, surfacing, at least one and probably two valve seats, at least one and probably two valves ... it's going to be close.
 
Ubergeekian said:
The people I went to don't do cast iron welding at all, so it seems worth asking people who do. I suspect the answer will still be "no" or at least "not economically". A new head will cost me £350-ish: the old one will need welding, surfacing, at least one and probably two valve seats, at least one and probably two valves ... it's going to be close.
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We sold hundreds of 1GM motors and they proved rock solid. Engines lasted well over ten years before corrosion head cracking was ever encountered. Plenty of folks attemped welding and the US has a far more 'can do culture' than the UK. The salt and other chemicals work their way into the iron making it difficult to obtain a clean weld even using nickel rods.

Big problem is that the corrosion damage is working away elsewhere. You spend respectable $$ thinking you have fixed the one problem and six months later head fails again either at welded repair or elsewhere. More $$ down the pan. Whacking a new head on ten year old engine is not the real answer either, you have to think seriously about an indirect cooled replacement.

This is a pretty well known characteristic of the 1 GM which has had its time, which you learn to to either accept or walk away from.
 
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