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Best method for cleaning engine blocks.....

101K views 20 replies 17 participants last post by  cerial 
#1 ·
I have had engine blocks hot tanked, jet washed, baked and tumbled, but it seems like none of these methods are better than the other. What is the best way to have a engine block cleaned????
 
#2 ·
It's almost impossible to beat a hot tank cleaning job, but the solution in the tank has to be reasonably clean. Most if not all shops push it too far before they change it out or rejuvenate it. Short of hot tanking it, and depending on how sludged up it is you can do a fairly good job with oven cleaner, paint stripper and other solvents. Pull all oil galley plugs out and procure some brushes normally associated with gun cleaning to get into the oil galleys. After you have done all that then take it down to the local car wash and give it a good washing. DO NOT however take a heavily sludged up block right down to the car wash and commence to blow that cr@# all over the car wash. That will get you banned from the car wash quicker than a muddy 4 wheel drive will.

Vince
 
#3 ·
I had had blocks cleaned by the methods I listed before I rebuilt them, but it doesn't seem like one method is better than the next. All three methods I listed, get the grease and grime off pretty good but I always have rust in the water jackets. Is there another method that machine shops use to clean blocks that will get rid of rust in the water jackets along with all the grease and grime?
 
#4 ·
onebadmerc said:
I had had blocks cleaned by the methods I listed before I rebuilt them, but it doesn't seem like one method is better than the next. All three methods I listed, get the grease and grime off pretty good but I always have rust in the water jackets. Is there another method that machine shops use to clean blocks that will get rid of rust in the water jackets along with all the grease and grime?
A real hot tank will dissolve the rust. Unfortunately, due to environmental requirements, most shops have stopped using real hot tanks and instead use steam cleaner tanks. This gets the crud off but doesn't touch the rust.
 
#6 ·
Due to EPA requirements. Most of the shops around here use a spray washer (like a big dish washer). The cleaner has to be compatible with aluminum and cast iron. Unfortunately what cleans rusty iron EATS aluminum.What cleans aluminum doesn't touch rust. Another problem is foaming of the detergent. Wrong combination and you have a LUCY show situation with soap bubbles. (been there). I personally use this system along with a bake and blast system. The bake/blast cleans all visable areas. But, is limited on some internal oil/coolant passages. Also you have to be VERY careful to get the spent blast media out of the casting. A few pieces left in an oil galley and instant bearing failure on startup. The blast media also tends to peen over the tops of lifter bores and exposed edges. These have to be chamfered ar reamed back to size.
The blocks look like fresh from the foundry tho.
 
#7 ·
We had our BBC jet washed and baked I believe, still had rust in the water jackets of course.

Any of you old timers heard about the vinegar trick? Drain the coolant, fill your radiator up with gallon of vinegar, the rest with water. Run the motor up to temperature, shut down and drain. Someone told me about it, but I've yet to try it. Anybody else hear about that?
 
#16 ·
I've done small parts in vinegar but don't leave them submerged for more than a day or so. Not sure I would do a running engine unless it was about to be pulled for rebuilding. Am about to try what Zimmo mentioned though.... Electrolysis - Rust Removal Will try a couple of old heads before sticking in a block. Yeah, I know this thread is old but it's what came up after doing a Google search....
 
#8 ·
i have a 1953 8ba ford/merc flathead engine block that we got out of the woods and have had machined and magnafuxed and cleaned a little bit but i need too clean the rust out of the water jackets and oil gallies does any one have any suggestions on how to besides using pipe cleaners?
 
#9 ·
block cleaning

i have used muratic acid,block off waterpump holes,and be sure core pluges ar in fill water jaket with 50/50 water and muratic acid. leave for 2 to 5 days.get muratic acid at hardware store(used to clean cement) be sure to use rubber gloves and eye protection,have a active hose readey as acid verry potent. good luck cliff
 
#10 ·
1953 8ba flathead merc/ford

i was putting the pistons and rods togather today the pistons i had no problems with but my question is that im using a 100horse merc crank and the rods are ford but 3 of them have oil relief holes and 5 do not do they all need these holes or not?
 
#11 ·
i was putting the pistons and rods togather today the pistons i had no problems with but my question is that im using a 100horse merc crank and the rods are ford but 3 of them have oil relief holes and 5 do not do they all need these holes or not?
Clarify the ""oil relief holes". The holes for the pin end or the squirt holes on the big end sides.
 
#17 ·
I have used the electrolysis method to remove rust from steel and it works good. Somewhere here on this site I wrote a couple of posts on a small electrolysis tank for using to clean small parts and it worked great. but I don't see why it would not work by scaling up to a plastic container like a plastic Drum to hold the block and a power source.. So a search on Electrolysis you should find the posts that show the basics of how to set it up. Good Luck and if you do it let us know how it worked. :cool:
 
#19 · (Edited)
I used a heavy steel drum (it made a great all-around electrode) and a DC welder (30-40A) for electrolytic cleaning of a seized block (water filled cylinders seized) Pressure washed it between overnight treatments. I was subsequently able to knock out all the pistons and rods with a wooden dowel.

Removed rust, paint, most oil and grease. Still needs a real hot tank for oil galleries etc after machining.

A subsequent treatment in a rubbermaid tub with wire rope for electrodes (within perforated vinyl tubing) will clean water jackets like nothing else. Ive done some really ugly heads like that. Limit the welder current or the water gets too hot for the plastic tub.

coat machined surfaces with WD40 before drying to avoid flash rust. don't use SS electrodes.

***People realize you can't kill cast iron with reverse electrolysis, once there is no rust left (to convert back to iron oxide (black) which washes off) the water soap solution just bubbles (hydrogen gas) until the power is switched off. I believe its the bubbles that loosen the paint and dirt etc.
 
#20 ·
I usually wash up a block before I start any mock up work and then wash it again before final assembly.


My preference is Tide and hot water - a lot of it. After a good washing, I use compressed air to get rid of the water, then use WD40 and paper towels to coat machined surfaces.



As to rust in the water jacket. I have one trick that I used a few years ago on a badly rusted block. I rigged up some pieces to fit the water pump bosses and pieces of lawn hose, then used a 110v sump pump to pump vinegar from a 5 gallon bucket through the water jackets and then back into the bucket. A couple of pieces of lexan and some head bolts worked okay for covering the heads - it leaked a bit but no harm. I let this contraption run for about 2 hours. I use the same setup to backwash my tankless water heater. And there was 3 gallons of vinegar in the bucket.
 
#21 ·
Leave the old paint on..
Assemble the engine(or pull if already in car)
Block the intake and exhaust with plates.
Soda blast the engine going right over the new seals.
Tape up intake and waterpump, etc.
VHT primer
VHT paint
Pull tape
Install water pump and carb.
Get up to temp ignoring the smell of the paint curing.

Simple, quick, cheap.
 
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