Block cleaning consern

Marklambert61

Marklambert61

Member
Team,

I rebuild a fair amount of motors, however I'm just starting my first Model A engine.

Here is my issue the machine shop i normally use normally cleans blocks by baking about 600-700 deg then follow by a water jet cleaning process.

Im wondering if heating a Model A block is bad idea?

What kind of temps can the babbitt bearings tolerate?

Mark
 
I think I read about 400 degrees and Babbitt will melt .

I think caustic soda will eliminate the Babbitt as well .
 
You need to do all the cleaning before the Babbitt is poured. If you're just repairing, then you have to hand clean, or plug water outlet, and soak with something like wood bleach ,and nutrulize.
 
I have had several Model A and B blocks thermally cleaned and have seen many more done this way. The block will withstand the temperature fine and the shot blasting after the oven cleaning does a good job.

Both the thermal cleaning and caustic bath cleaning process destroys the babbitt. The babbitt will contaminate the caustic bath and render that unserviceable to the shop doing the cleaning.

It is advisable to physically remove the babbitt from the block prior to any process cleaning and do not clean the block with the bearing caps attached.

The front and center caps have the babbitt "chemically" bonded to the caps and the vast majority of rear main caps have the babbitt just poured in place and attached by sprues from the babbitt into holes in the caps. The babbitt in the rear main cap that has the sprue attachment method is physically removed like the block babbitt.

If not repouring the main bearings, you are stuck with hand cleaning the block and treating the babbitted bearing surfaces as if they were regular insert bearings, that is carefully.

Hope this helps,

John
 
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