Best way to de-rust engine block

Huey

Huey

True Classic
I'm in the process of pulling the engine out. The entire engine and transmission need to be thoroughly de-greased and cleaned. But I notice the engine block is covered with surface rust. I am not interested in tearing down the entire engine, if I was to do that I would take the block to a machine shop and have it tanked. Without tearing everything down, what is the best way to remove the rust? I figure I could go over everything with a wire brush. Sandblasting would be great except it would get into every orifice.

Also, what color should it be painted afterward?
 
I can't help you with the derusting question (actually, I'll be interested in seeing the answers you get) but one caution.... If you do change your mind and have the block hot-tanked, you will need to replace the auxiliary shaft bearings, and that is a real pain because they are press-fitted and then reamed to size.
 
Lots of wire brushes, large and small. Gallons of Simple Green and Power Purple. Many cans of brake cleaner. Hours and hours of scrubbing. I didn't think to find out if there was a "stock" color for the engine. I just used silver engine paint on the block and oil pan. The head and cam box are just clean aluminum, not painted. Same with the intake. I did freshen up the looks of some of the mounts and pulleys with engine back.

Before pictures:
1500 Engine from a parts car

4 spd Transmission freshly pulled off the 1300 coming out of my 78. Yuck.


After pictures:
1500 ready to go.

4spd ready to go.


 
Jim, that looks awesome! I don't mind putting in hours of work to make it look like that. The silver looks good, too. I was thinking black but I'm really liking the silver.
 
Good luck with your project Huey.

Black would hide the drips better for sure, but I decided on silver for some reason. I was looking back at more of the photos and noticed that I used engine primer under the silver. You can see that I took the pan off as well as the head, but I was installing an MWB performance head in place of the stock FI head. You can see the yards of masking tape I used. :)





One of these days I will finish this project. The engine and trans are in the 78, I never got araound to finishing the wiring and plumbing.
 
After it is clean, try a rust converter. Then clean it again the next day and paint it. I've had good luck with the Permatex rust converter. You'll never get it perfectly clear of rust but you can get is super close.
 
Huey said:
I'm in the process of pulling the engine out. The entire engine and transmission need to be thoroughly de-greased and cleaned. But I notice the engine block is covered with surface rust. I am not interested in tearing down the entire engine, if I was to do that I would take the block to a machine shop and have it tanked. Without tearing everything down, what is the best way to remove the rust? I figure I could go over everything with a wire brush. Sandblasting would be great except it would get into every orifice.

Have you ever used "EvapoRust"? The stuff is amazing! Absolutely won't harm anything but really removes rust and restores metal. I've tried in several very rusty things and the results are the same - rust is simply gone. Its inexpensive and reusable. You have to "soak" things in it for a couple of days though. I can' imagine soaking an entire engine but I bet you could place towels on the rusty parts and keep them wet with EvapoRust.

Ed
Click to expand...
 
If you can get hold of some phosphoric acid(30-35%strength), that will help with the rust. A little Dawn dish soap in the mix will help with the contact time. Brush, rinse thoroughly. Be careful of flash rust. If you can't find it, let me know.
 
Stock color is a light grey as far as I know.

You don't need to go overboard on this. Wire brush on an electric drill to remove the rust that will come off.
Then just paint over the remaining surface rust. This will last for a very long time. The cast iron will not rust like a rusty body panel that you paint over.
You also don't really need any high-temp paint.
But since auto parts stores carry engine paint, it is easy to use that.
Either mask and spray paint of brush on.
 
Mine was grey under the grime.



I go with red, but that's 'cos all my iron block Volvos used red :)

You can always color match it to your cars paint ....

Edit: soda blasting works - easy to clean up. Just mask off all orifices, as you would with any prep involving wire brushes, wheels etc.,
 
degrease with your cleaner of choice, then us wire brush then use phosphoric acid (you can get this at Home Depot) to treat the rust then Ford engine gray spray paint.
 
I ordered some engine paint from POR-15 along with their degreaser. I've used POR-15 original "paint over rust" and their exhaust manifold paint in the past and had excellent luck with them. You can brush it on and it dries flat and smooth, great for painting over rust pitted metal. I've not used their engine paint before but I'll give it a try. Their products are pricey but worth it in my humblest of opinions.

I thought about the soda blasting. Harbor Freight sells soda blasters pretty cheap -- probably because they are cheap :p. I'll know more once I get the engine out but whatever way I go, I have my work cut out for me. Labor of love.
 
Has anyone tried dry ice blasting. We used this in the paper mill on the machines. Only clean up is what is removed(rust dirt) all blasting media just disappears, and doesn't bother seals ect.
I am considering having this done on bottom of mine, don't have to worry about heat distortion.

Stoney
 
the "outside" is NOT the important bit ......................

cleaning all the water galleries is .......

tap the oil galleries - so that you can at least clean out the oil ways properly.....

both are important (imho).

rgds
simon
 
Very true.
I have used acid to get the rusty layer out of the cooling passages of the block.
 
Simon Oaten said:
the "outside" is NOT the important bit ......................

cleaning all the water galleries is .......

tap the oil galleries - so that you can at least clean out the oil ways properly.....

both are important (imho).

rgds
simon
Click to expand...

Agreed and I plan to do a thorough inspection/cleaning of all coolant passages -- especially since there are signs of rust in the existing coolant.
 
phosphoric acid works - but needs a bit of time

hydrochloric - works very well ..........rinse very very very well !!!!!!!!!!

wear appropriate PPE (gloves / facefask / long sleeves / try not to breathe in fumes......), and don't get onto machined surfaces.

I use several fine paintbrushes, agitate with thin scrapers.....normally 3 or 4 goes to get a block "clean" inside.....I use a weak alkali to neutralise any remaining acid after water washing ......I try and blow off with petrol in kero gun so that water doesn't effect bores etc, then wd40 and dry off with air-line

rgds
simon
 
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