best way to treat a repaired aluminum head

[mike1157]

Since I've had this head for 6 months, I've known I've needed to talk about this for a little while now.

There are two obvious areas where my crossflow head has been repaired. One is at the rear where the two main water entry holes are, and the other is one of the water riser holes that will be blocked w/ a plug. I don't know if the guy that did the repair specialized in the process, so I have no idea how it was done.

Neither of these two areas are anywhere near the chambers, and are about as far away from the main combustion sealing areas as they can be, but I know how hot surrounding aluminum gets when it has to get hot enough to melt.

I've got too much invested in the combo to lose something based on head failures from a softened metal structure. You can see where the small repair has been dinked w/ a pecking hammer, there are 7-8 little pecks (probably to test the softness by the previous owner)

Now........I can take this bare head to Birmingham friction, and they'll put the head in their shot peen tumbler. In a minute or two the head will come out w/ a overall texture of suede, and be hotter than hell for about 15 minutes after that. I've used those guys enough times in the past that I know that two minutes will cost me exactly nothing.

Or, I can send the damn thing somewhere, and have it heat treated by some company that specializes in the process.

Question is.....do I need to do that? Is there a way to test whether the affected areas are any softer than the other part of the head?

 

[xctasy]

The casting was from Honda in Japan.
You won't have to re heat treat it, but if you want to, go for it. You can't ruin an Aussie X-flow alloy head.

The Honda Motor Company made these little canted valve heads better than Swiss watches, and they are practically bomb proof.

They were sent to Australia as a 114 pound ingot for 57 pounds to be removed by finished machining. That's why the casting had special identifiers, so they were able to custom make 9 generic types of head from one basic casting from 1980 to 1992.

Because of this, they are so dang strong, you can melt the alloy in the exhast valve, and have a torchdown, with a huge chunk melted out and undercutting, and by passing the valve seat, and just TIG weld it back up and your all peaches and good to go again. This happened to me in 1996, when a piece of RTV from the prevous owners propane conversion got stuck in the intake branch of my 2-bbl XE Falcon; my LPG 4.1 then suffered an lpg lean out in number 5 and 6, which leaned out No 5 and as a result blew a fire ring on the standard Monotorque head gasket, and ran at the hands of my wife for three days until I recoded the head, removed the RTV and put in a new 3 core cross flow 351 radiator to keep the hard worked six pack cool. My machinist, Graeme Page laughed and said its a shame the Cleveland heads weren't cast by the Japs. He had E&S head systems reweld the chamber, and with no new valve seat, just re-cut the old non unleaded fuel one, and loosely re-profiled the chamber, slapped it back together, and it yielded 27.5 US mpg on the open road and 15.9 second quarters for the next seven years until sold in 2003.

 

[gb500]

take the head to a place that has a hardness tester - a head shop should if they deal in alloy ehads.

ususally ball type affairfor brinel testing.

they can tell you if the head has gone soft in the areas repaired -and if that is significant - ie : the locations will be a worry..

my 'understanding' is that on the alloy crossflow heads from Oz , is that what you describe is a pretty common repair done to them

never had to do it - but understand for heat treating an alloy head all the ferrous parts need removing , then head is treated in solution , then needs full remachining as it will be distorted.so is usually only for high end rare heads

 

[Firepower354]

Weld em up, grind em down, pound it.
https://scontent-a-ord.xx.fbcdn.net/hph ... 7649_o.jpg

I worked at a shop that repaired Top Fuel heads. They'd shove an exhaust valve out the plug hole. We'd weld/machine/ship.

 

[MustangSix]

Unlike a part that undergoes recurring mechanical stresses such as a wheel, a cylinder head is mostly just a tea kettle containment vessel for fluids and gasses. Heat treating it to harden it doesn't add a lot to it's function, especially within its normal temp ranges.

I wouldn't worry about it. If the welds look good, run it.