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Block Cleaning (Paging Doc and Dart270)
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Author:  gmader [ Fri Feb 08, 2008 8:05 pm ]
Post subject:  Block Cleaning (Paging Doc and Dart270)
The local hardware store has quarts and gallons of Muratic Acid. If I am cleaning just one block, how much do I need? Also, if I remember high school chem, you add acid to water, but do not add water to acid. Is this correct?

Thanks,

Greg
Author:  SlantSixDan [ Fri Feb 08, 2008 8:54 pm ]
Post subject: 
Can't answer your quantity question, but you're right: Always add acid to water, never the other way round.
Author:  Dart270 [ Sat Feb 09, 2008 8:04 am ]
Post subject: 
Iron or aluminum block? I've never done this, but would guess if you want to fill up an iron block with solution, you'll want a pretty concentrated mix - probably 1 gal muriatic to 2 gal water. This is a wild guess. Yes, add acid to water.

Is this block already degreased?? If not, this might hang on and prevent penetration of the acid solution. I usually take my junk to a shop that can clean it all up in an oven or hot tank. I haven't done an Al block yet, though. Soon...

Lou
Author:  SlantSixDan [ Sat Feb 09, 2008 8:27 am ]
Post subject: 
Quote:
Iron or aluminum block? I haven't done an Al block yet, though. Soon...
Hold it! Acid will dissolve an aluminum block; this cleaning technique is only applicable to iron.
Author:  Doctor Dodge [ Sat Feb 09, 2008 9:29 am ]
Post subject: 
Yes, this process is for cast iron only.

Seeing that I always seem to be asking: "I wonder if this will work"...
I just acid cleaned the water jackets on a good used 170 engine, with the engine in "long block" form. (assembled with the head installed)
It worked like a "charm".

I usually do acid cleaning on empty blocks and tend to do the process as a first step, right after dis-assembly. Why? Because if there are any cracks in the block leading into the cooling system, doing the acid cleaning will make the crack(s) stand-out.
After the acid cleaning process is done I send the block off to the shop for their complete cleaning process and machine work. The shop's cleaning processes saves me the trouble of having to neutralize the acid I left behind.

See this photo for the assembled 170 we acid cleaned. That engine took just under a gallon of acid, right out of the bottle and the coolent passages were "spotless" 48 hours later.
If this engine had the origional steel shim head gasket, I would have never of done this aggrissive cleaning process to the motor but the head had been replaced at some point and a FelPro composition head gasket used.
BTW, we installed this 170 engine into a 64 Valiant and it runs great.
DD

Image
Author:  SlantSixDan [ Sat Feb 09, 2008 9:33 am ]
Post subject: 
I understand your "never do" caution regarding the shim-type head gasket, but I kind of wonder if it's possible the composition gasket might tend to "wick" the acid into the gasket itself, causing corrosion damage in the long run?
Author:  Tom Drake [ Sat Feb 09, 2008 9:40 am ]
Post subject: 
FYI

Hydrofluoric Acid – Used for cleaning iron and steel castings, in the refining of certain metals, for etching glass and for cleaning mineral sands. It is widely used as an aluminum cleaner and brightener and can be used to remove rust stains from fabric in commercial laundries.


If you choose to clean using acid start with a diluted solution and raise the concentration until you reach your desired effect. RINSE WELL!
Author:  Doctor Dodge [ Sat Feb 09, 2008 9:52 am ]
Post subject: 
Time will tell on that. If this engines blows a head gasket, I will a "data point".
You know me... I did a little testing on some scrap head gasket material before dumping a gallon of acid into this assembled engine. My fear was "wicking" into the gasket's metal core and then acid migration into the cylinder bores.
The sample of Fel-Pro head gasket material I soaked in acid for a week held-up extreamly well, we saw a little swelling along the exposed edges and little to no erosion of the exposed metal core material.

After the cleaning, baking soda neutrializing and final rinse, the engine went on the engine stand for oil pan & manifold installation. On the stand, we angled the engine so the spark plug holes were down, and turned it "round & round"... It turned easily and not a drop of water came out of the cylinders. (a good sign)
Again... this is "bleeding edge" stuff... don't try this at home! :wink:
DD
Author:  SlantSixDan [ Sat Feb 09, 2008 9:53 am ]
Post subject: 
Quote:
Hydrofluoric acid
Yahbut, read the informational labels on any of those HFL aluminum cleaners and you'll find it tends to attack the surface of the aluminum, leaving it open/porous and subject to more rapid re-corrosion unless some kind of surface finish is applied.

Your dilution idea is a good one if, for whatever reason, it is determined that one must use acid to clean an aluminum block.
Author:  Doctor Dodge [ Sat Feb 09, 2008 9:58 am ]
Post subject: 
I will take light bead blasting and jet washing only on my aluminum parts... and hold the mayo. :lol: :wink:
DD
Author:  SlantSixDan [ Sat Feb 09, 2008 10:00 am ]
Post subject: 
Quote:
My fear was "wicking" into the gasket's metal core and then acid migration into the cylinder bores.
I hadn't thought of migration into the bores...was thinking more along the lines of water/oil leaks.
Quote:
The sample of Fel-Pro head gasket material I soaked in acid for a week held-up extreamly well, we saw a little swelling along the exposed edges and little to no erosion of the exposed metal core material.
That's a good sign.
Quote:
this is "bleeding edge" stuff... don't try this at home!
But Will it blend? ;-)
Author:  DusterIdiot [ Sat Feb 09, 2008 10:05 am ]
Post subject:  Definately not...
Quote:
Hydrofluoric Acid
I worked at an Intel Fab and I got to see what happens when this stuff gets on someone's hand without protection/gloves... if the concentrated form it will burn, then crystallize the bones and blood in the affected area... the plumber affected went to the hospital and they saved what they could of his hand and wrist...

Very diluted solution...

-D.Idiot
Author:  Dart270 [ Sat Feb 09, 2008 10:44 am ]
Post subject: 
Yes, use a very dilute solution of HF. They say the damage to bone and connective tissue is essentially unrepairable, and the pain is excruciating.

I have used "mag cleaner" that includes HF on aluminum slots and such. Worked well to remove oxide, then hit it with polish.

Yes, Dan, you are quite right that HCl will eat up aluminum very fast.

Lou
Author:  SlantSixDan [ Sat Feb 09, 2008 12:54 pm ]
Post subject: 
Quote:
HCl will eat up aluminum very fast
as I remembered just a little too late years ago.
Author:  AndyZ [ Sat Feb 09, 2008 4:28 pm ]
Post subject: 
We use HF at work and it can be nasty stuff. One of the problems is Aluminum oxide is tough stuff, a lot tougher than just aluminum. Hf needs to be strong enough to remove the harder AlO2 and not damage the Aluminum underneath. This process needs to be timed so you remove what you want and then neutralized before you ruin the stuff you want to keep.
Hydrofluoric acid needs to be handled carefully. It doesn't typically burn the skin on contact but will be absorbed into the skin and will eat bone. No kidding. I would suggest using ample protection and have some calcium gluconate on hand in case of an accident.
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