block cleaning
 

I can have my A block baked and steel shot blasted by a local machine shop. My understanding is that it will be as clean as it can be. Would it be prudent to melt the babbit out before this is done and is there any chance of damaging the block by this?

Re: block cleaning
 

When you say "baked", do you mean "boiled out?" That would be the usual treatment for de-greasing. Following up with shot blast (glass bead) would be the next normal step - at least for those parts to eventually be covered by paint.

There is some risk in both. Boiled out involves use of a hot caustic bath - and the Ford main bearings are "tinned" in place. Any flaw in this tinning give place for caustic to remain and potentially loosen the remainder of the babbitt. Still, many do this and seem to get past it.

There is some risk in abrasive blast in that the babbitt, if left, can become "embedded" with either the grit, or the products of removal (iron grit and sand dust from the casting process, essentially.) As with the caustic bath, many do this and are able to protect the babbitts by overcoating with setting rubber, caps/shields, or even duct tape works.

If one is careful and give the shops doing the work full appraisal of your concern, they will probably answer to your concern.

If you elect to remove the babbitt, then you're starting with basically a bare block much as Ford did and precautions are lessened. If you have a block which is "clapped out" and beyond shim removal/filing the caps and the crank is egg-shaped in all journals, then by all means remove the babbitt since you're basically into a full rebuild.

There are merits and downsides to both methodologies. I myself did a de-grease "spot clean" using TM4 paint stripper (strips grease and dirt too) and then hauling the block into my powerplant where I had use of the blast cabinet. I masked the babbitt, camshaft holes, and cylinders and other need to be protected areas with three layers of duct tape.

As to removing the babbitt by melting, this can be done. I've always had my concern with melting/remelting babbitt, not the least of which is a change in chemical ratio in what you catch, what plates out in the cup you catch it in, or what oxidizes and has to be removed as dross later. Most babbitt pourers don't seem to have a problem with this but I always felt it better that the rebabbitter deal with the block/rods as they find them.

I currently have a block which has come to me just yesterday. It is bored over 0.030, but seems like a recent bore. Almost NO ring ridge at the top. The rods and pistons are gone as in not present, but the crank-pins seem near to original. It may have been a period rebuild which used an original crank - which were still available from various sources up into the 1960s.

It is a little rusty, but a glaze breaker seems to clean out the cylinder bores. I've priced connecting rods and pistons and this seems like it might be a viable engine WITHOUT a full rebuild.

I'm thinking I'm going to electrolytically clean this block. I've examined online and many who do this claim electrolysis does not seem to harm or loosen babbitt - well - some who do this.

Joe K

Re: block cleaning
 

In either case the shop likely would remove the babbitt as oven cleaning or hot tank processes would leave the white metal as a contaminate and not a good one. Oven cleaning is a good process but the shot only cleans the scale on the outside of the block. The water jackets would have to be poked and prodded to loosen old rust and shot out but it would come out easier than any other cleaning process.

Re: block cleaning
 

To get our block really clean we have them acid cleaned at a place that does metal stripping, bodies etc., cleans the rust out of the passages, but Babbitt has to be removed.

If the Babbitt is still good we hot tank the blocks without removing the Babbitt, our shop that does the work can lower the block into the tank and leave the Babbitt above the solution. Hot tanking is good for general cleaning but does not remove rust.

Re: block cleaning
 

You can physically remove it fairly easily and pry it out.Drill out what’s left where the journal Babbitt anchor holes are. They will be obvious .
Larry

Re: block cleaning
 

We do this to every engine that will need a rebuild.
It's the only way to get it cleaned,rather than acid dipping or hot tanking or jet wash. The blocks just don't get cleaned throughly, "washing or dipping, " there's always something left behind.
Thermal cleaning/shot blasting removes all the debris along with majority of rust on/in block along with cleaning water jackets.

Proven that the blocks come out lighter after cleaning.

You don't have to melt the babbit out prior to thermal cleaning as it will melt out in the machine. Unless you want to use the old babbitt to make fishing sinkers.
http://www.jandm-machine.com/cleaning.html

Re: block cleaning
 

The main problem with electrolysis is that it is "line of sight" between the 2 poles, so no going around corners.

John

Re: block cleaning
 

You can say what you want or what the EPA wants you to say, but the laws of physics still apply.
The only things that will dissolve rust and scale are chemicals.
No amount of scraping, chiseling, scratching, media blasting or brushing will get ALL of the rust and scale out of the water jackets.
Luckily there’re still a few metal strippers left around the country.

Re: block cleaning
 

I can get past some of that with time. As one of the sites I've seen indicates, you can go with a bit less amperage, but leave it longer. The results are less "black" residue and more uniform conversion. I have done this before leaving a piece up to a week in the bath - just to get conversion into those "hidden corners" without having to reposition the electrode. Line of sight the bath is - but the electric field of the bath is pervasive and total.

I've actually thought of the partial immersion idea mentioned above by immersing in the bath UP TO the babbitts, this to positively remove any possible influence of the bath on them. The couple of inches above the waterline including the skirt of the block can be scrubbed by the armstrong method leaving the babbitt totally alone.

Tomorrow, if yard work permits, I'll do a disassembly of the block and make some more better measurements.

Joe K

Re: block cleaning
 

It makes me nervous to say this but I pulled a block out of the ground and cleaned it electrically but I left the block in solution for 10 months or so. I occasionally had to replace the cathode (or anode??) rods but the block checked out great and was rebuilt with new babbets and it was magnafluxed to make sure there were no cracks. It has run fine now for the last 3 years or so. Jack