Cleaning a block- Hot tanked in acid?

[Tim Ayers]

OK, in the past, I've had blocks hot tanked, one that was supposedly baked & blasted (but I don't think it really was done as claimed), and cleaned the old fashioned way of prodding, poking, scraping, squirting inside from all angles.

I need to have another block cleaned and I found a well respected shop kind of near me. When I called him today, he said he doesn't like to do "bake or blast" flatheads due to possibly damaging the decks.

I've never heard that before. He is recommended putting it in his hot, ultrasonic "acid" (I didn't ask what type of acid is used) tank.

He let's it sit for 4-5 days and then dunks it in a neutralizer bath. He claims it will come out as clean as new.

Has anyone used this method? I know a bunch of guys here swear by the blast and bake method.

[papanomad]

4-5 days in acid sounds scary! bake is the way to go. I doubt if acid will have any affect on grease.

[Tim Ayers]

Originally Posted by papanomad

4-5 days in acid sounds scary! bake is the way to go. I doubt if acid will have any affect on grease.

Kind of what I was thinking.

The gentlemen knew his stuff. Immediately knew what I had when I told him what year flathead it was.

[Tim Ayers]

I'm leaning towards finding a shop that will bake & blast it.

[JSeery]

Any acid process I am aware of removes good metal along with rust.

[flatjack9]

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I have had many blocks baked and blasted. I have never seen any damage to any of the surfaces and neither has my machinist.

[flatheadmurre]

I stopped using shake and bake on anything i don´t plan on machining the surfaces on.
I use a caustic solution that takes dirt paint and rust down to original cast iron.
You can leave it in but it doesn´t do much good to leave it more then over night.
Still needs a bit of manual aid with a pressurewasher in the waterjackets to get all crud out.
The thing with heat is that there´s always a chance that any built in stress and tensions get released...so you may get a warp...
Shake and bake is prefered cause it´s cheaper then the chemicals and the enviromental guys from the city can´t whine about hazardous material handling...

[JWL]

I have had blocks done with most processes and bake-n-shake is superior. However, there could be a case made for the use of acid on internal coolant passages.

I sold a Lincoln V-12 engine to a friend who used an acid dip "over the weekend" only to find all surfaces etched .002, Lifter bores oversize, all gasket surfaces smaller, threaded holes loose, main and cam bearing bores oversize, etc etc. Basically destroyed a beautiful V-12 block.

[john in illinois]

I use Redi Strip in Indianapolis. They use a special caustic solution that does not damage block. I notice they are now called pro-strip. They do a lot of large Diesel engines and I think that gives them the cash flow to afford all the EPA regs.

http://www.redistripindy.com/

Small machine shops do not have meaningful hot tanks anymore due to regs.

John

[Ol' Ron]

During the 12 years I ran Nostalgia engines I used only Shake and bake cleaning, then I rolled the blocks over a piece of plywood. almost nothing came out. Maybe it was just the shop that did this, but I never had a problem with over heating.

[Tim Ayers]

Originally Posted by Ol' Ron

During the 12 years I ran Nostalgia engines I used only Shake and bake cleaning, then I rolled the blocks over a piece of plywood. almost nothing came out. Maybe it was just the shop that did this, but I never had a problem with over heating.

I'm thinking this is the route to go. A lot of good points regarding not doing acid.

[42Ford M-H]

Google Molasses cleaning engine blocks, basically its an acid bath. Plenty of success and horror stories to keep you reading for hours Some of the horror stories it was obvious they were left soaking waaaay to long. Sad day when you find out you ruined your block

[marko39]

i had a 8ba baked and blasted and found the blasting media still in my oil galleys when i brought block home. that alone worries me as a tiny bit of that crap can ruin a rebuilt engine. my brother claims this was the demise of his old jeep engine he took to the same shop which is no longer around. Mark

[KiWinUS]

Shake n bake here Tim done hundreds of engines this was & never an issue
Cheers
Tony

[12cliff23]

my 2 Pennys worth. the ph scale is 0-14 lowest number is acidic 14 is basic. basic Is the caustic soda things. this can be a better cleaner of things, not only metal, and tends to be easier to neutralize and dispose of . as I remember is also more damaging to things that might be left inside the block
sure someone will fill in what I don't remember
cliff

[Pete]

I use electrolytic acid strip.

[Tim Ayers]

Originally Posted by Pete

I use electrolytic acid strip.

Pete: Like Redi-strip?

[deuce_roadster]

I used Redi Strip when a business was near me and in my opinion it is superior to any other cleaner/rust removing process. It is a BASE not an acid and they run electricity through the object and only rust is removed. Besides 2 flathead blocks, they stripped a 34 sedan delivery body for me. Sadly, they were illegally dumping the residue and were properly shut down and fined. If you can find a Redi Strip franchise within reasonable distance use it.

[Pete]

Originally Posted by Tim Ayers

Pete: Like Redi-strip?

Probably. I am not familiar with that company.
The company I use, uses acid.

[Tinker]

Seems like overkill. Certainly if you aren't machining a block, or if the block has been machined/decked previously.

Couple of old heads and pumps routed with whatever acid you wanted to run through it would work fine. or some mechanical tools (coat hanger) for a runner non-build works wonders.

I've used muriatic acid on a couple hit/miss engine hoppers. Real nasty stuff, leaving it in a garage once open can attack metal. Most pool supply places have it, every florida pool guys truck bed was rotted out from it. Neutralizing it is a good idea as it will continue to eat metal.

On non-coolant block castings I would think it seem a bit much. But I don't know...





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