Flathead block cleaning

Kahuna

Kahuna

Well-known member
Most of us that have, or are working on these silly flatheads, are aware that the insides of the water jackets can really be full of crud, etc.
I wonder if anyone has just taken a block, without using pokers, drill rods, etc., and just poured in something like Evaporust or another product & have any great results to share?

The engine in my car, I cleaned as thoroughly as I could, using long screw drivers and other tools to get all that crap out. But beyond that, I didn't use any cleaning agent like the Evaporust, or CLR, or Muriatic acid.
Just wondering what some of you wiser guys might have done?

I don't currently have an overheat problem, but if it becomes an issue this summer, I thought about just draining the system and filling with Evaporust or a like product, AND just driving it for a while

When I had my 39 Coupe, I used the Vinegar with a good, I think, result.
Jim
 
i believe there are several threads on this topic. i know old Henry gave a good show using water pumps, and others have done the block. google evaporust ford barn and i'l bet theres plenty to read
 
drain flush and fill with cheap vinegar and drive it thru at least three heat/cool cycles, you won't beleive what will come out. flush out the gook and fill with water and baking soda and flush again
 
any acid is a no no for the radiator. acid will go after the solder first. thats the beauty of evaporust, non acidic.
 
When I got my car it was running hot. I could see the tanks were leaking on the radiator. I replaced the radiator and water pumps. When I drained the radiator the antifreeze was black. Turns out it was filled with pure antifreeze which had become apparently quite acidic hence the seams leaking. On a bright side the inside of the block looked like brand new cast iron.
 
I have all my blocks baked cleaned, after pressure testing. Inside comes out prety clean after you roll it aronnd on a piece of plywood for awhile. As for a running engine, I think it's a crap shoot, you do your best??
 
Ol Ron
I think that block baking is an excellent solution to getting a clean block.
But, that facility is not available in all areas. Wish it were
Jim
 
I did the "Evaporust" thing. I thought it was well worth the effort. I posted one of those threads (with pictures) "cas3" was referring to.
 
Do not use muriatic acid in a cast iron block. It is difficult to get it all neutralized after it seeps into all that porous iron and it will keep on slowly dissolving the casting wherever it is.
 
ursus said:
Do not use muriatic acid in a cast iron block. It is difficult to get it all neutralized after it seeps into all that porous iron and it will keep on slowly dissolving the casting wherever it is.
Click to expand...

I'm sure there are pros and cons of the stuff but that it will work indefinitely after being neutralized and run with anti freeze, or even water, does not seem possible.
 
I used the "Evaporust" treatment and was very satisfied with the results. However, this was on a good engine with all cylinders over 100 # and 25 lbs of oil pressure at idle. There was no way I was going to tear it down. If, on the other hand, I was starting with a bare block, I would certainly use other methods.
 
Only bad with evaporust is that it doesn´t take oil and grease so you need to run a degreaser first for a good result.
For rebuilds i use a caustic hot tank that takes all but the castiron away....a dipstickmount on an oilpan doesn´t last 20min...i know the hard way...
 
At our shop we have a "hot tank" filled with a special solution. All blocks go thru this before any rebuilding is begun. For those who plan to do the work themselves, we clean the block and do a crack check at our standard hourly cost with our Magna-Flux. Check good rebuilders in your area to see if they have that service.
 
Kahuna said:
Most of us that have, or are working on these silly flatheads, are aware that the insides of the water jackets can really be full of crud, etc.
I wonder if anyone has just taken a block, without using pokers, drill rods, etc., and just poured in something like Evaporust or another product & have any great results to share?

The engine in my car, I cleaned as thoroughly as I could, using long screw drivers and other tools to get all that crap out. But beyond that, I didn't use any cleaning agent like the Evaporust, or CLR, or Muriatic acid.
Just wondering what some of you wiser guys might have done?

I don't currently have an overheat problem, but if it becomes an issue this summer, I thought about just draining the system and filling with Evaporust or a like product, AND just driving it for a while

When I had my 39 Coupe, I used the Vinegar with a good, I think, result.
Jim
Click to expand...

Hey Jim,
Well, if you went thru the processes that you describe to get rust chunks out...IMO, that was the perfect time to use rust eating product , i.e.-evaporust. I've used this product and have some now.

But, I just did a block, running in the car, with 911Rust. Mixed it as instructed. Ran engine driving for several days. Drained mixture (BLACK when done). Inspected radiator. It is nicely clean ! Put fresh water thru it to see how fast it drained as proof of thoroughness of cleaning. Emptied as fast as possible. Block showed no evidence of rust when flushed. Add anti-freeze and it's good.
Difference between these two products....pricey evaporust vs less costly 911 rust. Both seemed to do the job. Good to have good choices, eh :)

I will buy/use 911rust from now on.
 
I cleaned the block on my current build using my electrolysis tank.
Dropped it in and left it about a week. Results were amazing.
 

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Well, I went ahead and ordered the Rust 911 yesterday.
When done, I'll post the results
Thanks all
Jim
 
I'm glad you all brought this topic up. I was wondering myself what to do to clean out the water jackets

Sent from my SAMSUNG-SM-J120A using Tapatalk
 
All of this will work on rust, but not the core sand and wire. I have always had to remove it by hand. You can get up to a coffee can of crude out of some of these blocks.
 
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