Peening Main Bearings
 

There is probably an obvious answer to this question but I will throw it out there anyway: There has been a great deal of discussion around peening the rear main bearing on the block side. Should all main bearing saddles in the block be peened in addition to the rear main cap (later cast cap)? How much time do you have to remove the fixture and begin peening before the window has passed?

Thanks, Steve

Re: Peaning Main Bearings
 

I peen all of the bearings except for the front and center caps, which are steel and tinned. Any peening of these will loosed the Babbitt from the cap. I peen mine as soon as I get the molds off, this way the bearing is still hot and pliable, easier to peen. Doing this while hot (while it is cooling) will create a bearing that is tighter to the bore and last longer. I would say that the quicker you can get the molds off and start peening , the better.

Re: Peaning Main Bearings
 

"Agree"

Re: Peaning Main Bearings
 

Peening the bearings as soon as the molds come off suggests that the peening marks are reamed-out when sizing the bearings. Is this the case?

Re: Peaning Main Bearings
 

The bearings are cast undersized and line bored to size after peening. This way the molds are small enough so that any misalignment and undersize of the crank can be taken care of during boring. K.R. Wilson used reamers in standard size because you were supposed to buy a new crankshaft when yours was worn.

Re: Peaning Main Bearings
 

Here is a NOS factory A rear main cap peened and ready to be installed and cut to size.

Re: Peaning Main Bearings
 

Would you pour 1 bearing at a time then remove the fixture and peen install the fixture and repeating for each of the block bearings? Just thinking of how long it takes to heat the block in preparation for pouring.

Re: Peaning Main Bearings
 

Smitty are you planning on doing your own pour?

Babbitt is actually very complex to pour as there are a bunch of rules. There is a lot of science as your goal is to have small crystals form.

It starts with rapidly melting the cut up babbitt in a pot that is clear of any old babbitt. You need to have significantly more babbitt in the pot then you will use. There are mixing techniques and finally pouring into a cold (relative to the babbitt) block that is actually hot. You need a rapid cool to ensure small crystals, but warm enough that you can get the babbitt in without voids.
My brother did a significant amount of trials with old babbitt. Pouring it in and chipping it out to make sure he knows he is getting the babbitt in right. Then practice in peening and so on.

At any step it is easy to introduce seed crystals that will allow for larger crystals which cause micro crack formations.

It is very interesting reading the technical journals.

Re: Peaning Main Bearings
 

Yup, I am going to tackle it soon. Think I now have everything I need...

Re: Peaning Main Bearings
 

Does anyone know who, if anyone, that sells new equipment?

Re: Peening Main Bearings
 

There is a person who makes and sells new line-bore equipment.

Re: Peening Main Bearings
 

Gene French is the guy that make them;
http://www.mtfca.com/discus/messages...tml?1509169848
His number is in the ad. He also sells on ebay.
vintagemotormachine

Re: Peening Main Bearings
 

You can get an older line bore set up and they come with all the Ford locating fixtures.

I believe they typically sell for $2000.

There are some advantages to a KRW set up. Especially if the cutter is adjustable and the reamer ground to do undersize. None of it is cheap for the good stuff. We have found full Ammco and Kwikway line bore setups with the Ford tooling in the $200 to $400 range. Never know what shows up on Craigslist if you look frequent enough.