Alloy Head and amount of Corrosion?

[Anonymous]

Im keeping an eye out for an early alloy head. Does anyone know how to determine simply if one has a lot of corroson or if one is in good condition and has little corrosion. If I port it latter Im a bit worried about wall thickness etc. Anyone got a pick of good or bad or both to compair?
Cheers Tim

 

[alloydave]

Tim , a visual inspection is about the only way you can check for corrosion .Theres plenty of old heads around so i guess it will be a case of finding one that looks good in the water galleries .The thing to watch for in the old alloy heads is HARDNESS. Heres a little bit i found in one of my books ...
Most aluminium cylinder heads will have begun to soften when exposed to temperatures between 200 to 250 celius(392 to 482 fahrenheit).At 250 to 300 c the softening will have become quite severe making the cylinder head not suitable for service .For this reason ,even with the difficulties mentioned above , it is very important to hardness test any aluminium head when the engine is known to have overheated or when repair work such as welding has been carried out on the head.Localised hot spots within the cylinder head can result in localised soft spots so it is essential that the testing is carried out over a number of positions on the head.In addition the sealing surface of the cylinder head particular attention should also be paid to the mating surface of the cylinder head bolts.Indentations on the head mating surface resulting from where the bolt head has sunk into the cylinder head is a sure sign of softness.
(Thanks to RON at NZ GASKETS )
Tim , you can get a hardness tester from most good parts places ,they go for about $50 nz . The difficult part is finding out what specifications ford use on there hardness test ,this im not sure on.

cheers Dave

 

[xctasy]

I guess you just use the Brinell number of 90 for the T 356 alloy. We had a big mutha device at the laboratory. Like this

The specs for the T6-356 alloy Honda used is Sourced here:-

http://www.google.co.nz/search?q=ca...f+Rockwell+Hardness+for+the+T+356+alloy&hl=en

You'd have to test in five positions, and then take the one which measured best.

Field test devices are more likely to measure Rockwell Hardness, and the repetability may not be good. I'd love to get anything for less than 4000 bucks!

 

[Anonymous]

Thanks alloydave and Execute.
Execute.
Im pleased youve got a sence of humour mate.
I think I would do well to buy one of those as in your picture first. I could carry it around in a car trailer to the car wreckers in search of an alloy head and run an extension lead to it (I had a big enough problem telling them I wanted to take the head off to check the bore before buying on the last occasion. Wait until they see this!).
Only problem with those is they are rather large and how do you tell a good secondhand one from a new one as Im guessing they are pretty expensive to buy new. To be able to afford it Ill probably have to get an old one with lots of corrosion.

Cheers Tim

 

[xctasy]

I have given the matter considerable thought. I suspect we could ask SuperMag what the impact diameter of a slug gun pallet is at point blank range. This would be cheaper. Only problem is you may get, like, 40 alloy heads for free before you got to conduct the tests.

Hmmmm. Back to the drawing board....

 

[addo]

If you wanted to get really fussy, any place that does aircraft certification ought to be able to hardness test, X-ray and then put the whole lot on paper... It will run to six or eight hundred, though. I would love to see a Brinell machine towed behind a hot Corty, registration HARD4U.