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Crud in flathead motors

Started by Steve Passmore, July 19, 2017, 12:05:30 PM

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Steve Passmore

There's been a lot of discussion over the years and more recently about the build up of scale in the back of the flathead engines and flushing the block to remove it.   I thought I would share these pictures of a 346 engine I am at present dismantling for anyone who wonders what all the fuss is about.  You can plainly see the buildup of crud and I want to reassure anyone thinking of just removing this with water that you cannot.  This is almost solid, 3" to 4" deep and can only be loosened up with a steel rod and hammer down through the water holes then high-pressure washing.
Even just removing the core plugs will not work as the majority is way out of sight of those orifices.
I never attempt this job with the engine still in the car. The mess is horrendous.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

Quentin Hall

Had similar build up in 331, 365 and 390s. Has anyone tried a mild phosphoric solution. I remove rust from badly corroded pieces in a 1000l bath but I have never used it in an engine.
   The worst corroded pieces come out beautifully clean after a week of soaking.  Phosphoric is non corrosive to alloy and only removes rust and scale and works best when heated so I think it would be a winner. Any advice or criticism??
53 Eldo #319
53 Eldo #412.
53 Eldo #433
57 Biarritz
53 series 62 conv
39 Sixty Special Custom
57 Biarritz

Bobby B

Steve,
Hi....Please show me something I haven't seen yet..... ;D ;D ;D
                                                                            Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

V63

Phosphoric Acids are corrosive to alloys? So is sodium hydroxide (Lye) . Dilution is the trick. I have isolated the solution to just the block...and its VERY effective. The waterpump can be adversely effective by the abrasives in solution. I try and remove the waterpump and block off ports. I will use acid (muriatic is easily sourced) first...and when finished, follow with an alkaline (Lye) product. Super clean (purple container) is a good one.

Last patient was a 1926 Packard

Caution: the resulting muddy river will permantly stain cement drives!

Quentin Hall

I made an error. Phosphoric is corrosive to some alloys eg. Diecast. It is good on aluminium, brass and copper. Solution to about 5% .
53 Eldo #319
53 Eldo #412.
53 Eldo #433
57 Biarritz
53 series 62 conv
39 Sixty Special Custom
57 Biarritz

CadillacRob

Same as my 50 and 56.  I cleaned it engine still in the car.  Knocked out the freeze plugs and used a coat hanger and a lot of water.  Messy job.
1950 series 61 sedan
1956 coupe de ville

Steve Passmore

Quote from: Bobby B on July 19, 2017, 07:54:31 PM
Steve,
Hi....Please show me something I haven't seen yet..... ;D ;D ;D
                                                                            Bobby

This was for the uninitiated Bobby ;D  Not the seasoned hacks like us ;D
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

Bob Schuman

Cadillac published a block flushing procedure in a 1947 issue of the Cadillac Serviceman that went to dealers. It involved water pump removal, and disconnecting the upper radiator hoses, removing one head bolt at a time, starting with the bottom rear bolt of the left head, then flushing with water while injecting compressed air into the water jacket through the hole from the removed bolt, using a piece of metal tubing to reach the bottom of the water jacket. Then repeat, working forward on the bottom row, then on the middle row, then do the same on the right head, so that at each hole the flushing water runs clear. I did this on my 41 years ago and was amazed at the sludge and crud that was flushed out through the water pump hole in the block. That was on an engine that did not have an overheating problem.
If the scale is hard as in Steve's photos this Cadillac procedure may not do an adequate cleaning job.
Bob Schuman
Bob Schuman, CLC#254
2017 CT6-unsatisfactory (repurchased by GM)
2023 XT5

Bobby B

Bob,
The scale is more like Cement. Actually Iron Cement..... :o Using Water pressure is like whistling in the Wind.......
                                                                         Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

m-mman

Can you possibly scrape too hard???

I had a friend with a 1960 that he wanted to use on a cross country trip. It ran well enough but it was old and had leaks.
I pulled the engine, changed the pan gaskets & seals and pulled all the core plugs and did just as was described here. I Scraped out lots 'o rusty crud and flushed with water.  (Of note at this time, I did not pull the heads)

Reinstalled, it fired up but it suddenly had all the symptoms of a blown head gasket(!) or a cracked block(?)  :-\   Instantly overheating, bubbles in the radiator and combustion gasses in the radiator.

I pulled the heads and replaced the gaskets 3 times! The last time I swapped some good heads I had laying around.  STILL it was getting combustion into the radiator.  >:(

The clock was running so I yanked a short block core from out back and sent it out for a quick rebuild. I then installed the (rebuilt) heads that had been on the overheating block and all the problems disappeared. Car is running fine to this day.

My conclusion was that somehow I had removed enough rust that I uncovered a 'crack' or 'rust hole'. Perhaps I broke the block by ramming the rods & screwdrivers into to break up the rusty crud?

Who will ever know. In the end I threw the 'overheating block' out back with the idea that I would someday dismantle it for a close inspection, but now I just see it as a parts source. 
Never had that happen before and hopefully never again.   ;)
1929 341B Town Sedan
1971 Miller-Meteor Lifeliner ambulance
Other non-Cadillac cars
Near Los Angeles, California

CLC #29634

Bobby B

Quote from: m-mman on July 20, 2017, 07:47:58 PM
My conclusion was that somehow I had removed enough rust that I uncovered a 'crack' or 'rust hole'. Perhaps I broke the block by ramming the rods & screwdrivers into to break up the rusty crud?

I highly doubt it, and would put my money on a hairline crack or super porous block/cylinder walls, if it was as bad as you say it was. I would've sent it out to be magna-fluxed just for closure....
                                      Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

Steve Passmore

I think it would have been a flaw hiding there under the rust which would have reared its ugly head at some time.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe