The Ford Barn - View Single Post - New Babbitt Mains

rotorwrench · 10-29-2022, 10:24 AM

A lot depends on what type of align boring machine the builder has and what shape the crank is in. The mains are generally sized to the crankshaft journals to be used. The clearance should be close but it has to have some clearance to allow oil to get in there. It should be good with .001" to .0015" With less than .001", it' going to be tight. As long as the caps are shimmed properly at the outset, follow on adjustments can be made if necessary.

Ford turned the engines with the big electric motors and monitored the current draw on the motors. They had it down to a science for their initial bedding in process. If it took to much current to turn then it went back to a separate line for repair consideration.

I'm not one for running newly overhauled engines with no way to pull a load on them. They won't break in well with no load. Some get lucky but I don't like to leave things to chance.

10-29-2022, 10:24 AM	#10
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,520	Re: New Babbitt Mains - How Tight A lot depends on what type of align boring machine the builder has and what shape the crank is in. The mains are generally sized to the crankshaft journals to be used. The clearance should be close but it has to have some clearance to allow oil to get in there. It should be good with .001" to .0015" With less than .001", it' going to be tight. As long as the caps are shimmed properly at the outset, follow on adjustments can be made if necessary. Ford turned the engines with the big electric motors and monitored the current draw on the motors. They had it down to a science for their initial bedding in process. If it took to much current to turn then it went back to a separate line for repair consideration. I'm not one for running newly overhauled engines with no way to pull a load on them. They won't break in well with no load. Some get lucky but I don't like to leave things to chance.