Technical Question re rust in Flathead water jackets

Hello!

Having recently acquired my first early Ford based car since my Model A days in the 1970s, I subsequently picked up two 8BA flathead motors. One engine is now torn down and is awaiting inspection at the rebuilders. The second engine is an older Sears/Allstate rebuild which turns over, has minimal cylinder bore wear, a tight bottom end, little oil sludge, and no visible cracks to my amateur inspection. I would like to see if I can get it running without tearing it down further for a full rebuild.

My current concern is the substantial amount of rust in the water jackets. I can run the heads through my blast cabinet, but there is substantially more rust and scale in the block. I plan to pull the water pumps and blast it out with compressed air, but I prefer to stop short of hot tanking, acid dip, electrolysis or anything else that would require a complete tear down.

Does anyone have any further suggestions for water jacket rust and scale removal? Has anyone tried the EvapoRust/Metal Rescue/trisodium citrate type treatments?

Thank you in advance for sharing any successes or failures.

Barry in Ohio

 

Take a section of old speedometer cable or 1/4" wire cable and chuck it into an electric drill. Feed the cable down the water jacket holes and run the drill to break up the rust. Running the drill in reverse will help keep the cable from unwinding. If it's on an engine stand you can flip the block over and most of the crap should fall out. You could also blast it with air. This tip comes by way of Jim Brierley, and while he intended it for bangers, I did it on my 8ba as well.

 

I was in the same situation about 10 years ago with a '51 Mercury engine I bought 20 many years before. It had supposedly been a "good runner" when pulled. I stored the engine under the stairs in my shop for about 20 years, and finally decided to use it. I pulled it out and it turned over easily. I mounted it on my engine test stand and checked the compression. Over 100 on all 8, to my surprise. So I replaced the carburetor and all of the ignition parts. It started right up and ran great. At this point, I had the same apprehension about the cleanliness of the block that you have. I ran a couple of plain water only flushes and then one with a can of commercial chemical flush. During this period, the engine was mounted on my test stand with a radiator and fan so I could run it for a while while performing the flushes.. After this I ran three Rust-911 (like Evaporust , only cheaper) flushes. Each time I ran the engine up to operating temperature and let it run 5-10 minutes more. I then let the Rust-911 solution sit a couple of days to work it's magic. The first run came out almost black when I drained it. A couple of more runs, and it came out clear. Here is a photo through the front water pump openings when I was done.


Like you, I did not want to disturb an apparently good running engine to be able to do a conventional mechanical rust and crud removal, so I did it this way. I think it turned out fine.

I have been running this engine in my '51 Ford club coupe for the last 10 years with no overheating problems. The engine is mildly modified with custom fitted Edmunds heads, a Rochester 2G carb, and a Mallory dual point. It runs strong, but now, after 10 years, is starting to blow a little oil at high speeds. Oil pressure is up to factory specs and the only time the heat starts to build up is after about 10 minutes over 70 on the freeway (3.55 gears, no OD). I think it has more to do with the crummy aerodynamics of the ol' shoebox, than any conventional cooling system problems. Back off to 60 for a few miles an it cools right down.

 

Pull the pumps, poke around, dislodge, and remove all the rust, casting sand, and core support wires that maybe in there.