For Sale: 2 x Cracked 12g1316 heads! paid $200, will let them go today for $150! Head finding is starting to get costly...

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2002 TopKart Viper with Blueprinted Yamaha KT100S @ 17hp. 160kg.

Can a cracked head be used? (I mean, fixed first obviously)


Cheers,
Peter.

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Click here for the Turbo Conversion Thread!

Short answer is yes - not ideal and it depends on the location and on the extent of the damage. The engine reco guys have a series of screw thingys that stop the crack spreading and then they can weld over the crack and die grind it down to normal.

If heads are so rare (as in vintage and veteran cars) you often have no other choice. Some mini heads are at about that point.

There is a guy in Woywoy on the Central Coast that does some sort of jiggery-pokery with Cast-Iron "Brazing"
He basically berings the head up to temperature and uses a special filler rod (cast iron ?) to repair the cracks...
I've seen an "S" Block that had put a rod out the side repaired like this ....
Alsmot undetectable after the repair...

But I assume its expensive......probably more than a new head...

Good luck
J

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I would never use one to many variables

Steve

You can also plug the crack. there are many people who cast weld, Problem is that they may fix one crack but cause another when fixing.
Unleaded seats can somtimes retain a crack also and other times the crack wont ever get anyworse and it will never be a problem.
Asuming all the heads people buy come off running cars?

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*Reasonable pricing
*I come to you..
Jay: 0431404607

Short answer to all this is, is yes cast iron heads CAN be welded properly, successfully- and I was trained how to do it back in the 60s.
But if cracked in the chamber (as is usual) it involves slow preheating (preferably) in a furnace to a dull red heat, oxy welding with cast iron filler rod and flux on the hearth of the furnace, then SLOW cooling- preferably put it back into the furnace (which is shut off) to cool down overnight.

These days most places are in a hurry. They use shortcut methods- like stick welding with nickel or nickel/iron rods, or they TIG it with SS. Depends where the crack is but, if in the combustion chamber between the valves (the classic Mk1 S spot) I wouldn't bother with these methods.

Whether it is worth fixing depends on what degree of work it's had (eg a full race head), but if just a stocko one it's much easier to go find an uncracked one.
There are some out there.....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.