Do i have an odd one? 59AB

Mr 42

Mr 42

Senior Member
I have an 59 AB that i got in parts. And it was shimmed with aluminium foil, and it seam's to have worked OK. But its a bit odd in my book.


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Can anyone tell me the standard outer diameter of the main bearing's ?
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The crank journal size is 2.499". The main bearings are captivated in the housing. So the bearings wear on the journal surface. A poor "shortcut" for rebulding was to shim the OD of the bearing with adhesive shims (.001 to .003 thick to squeeze the bearing to a smaller ID and take up the wear. Quick and dirty. I cannot tell for sure but it looks lke the shim on your bearings covers the oil hole!! Maybe the experts will weigh in to be sure my comments are correct. John
 
Ive read somewhere about oversized Caps, mostly on European engines.
That the reason ive asked for the outside diameter.
 
It was very common year ago to shim the old bearings to take up clearance. If your rebuilding the engine, just install the caps and mic the bearing bore. It's probably std. I have the size out in the shop. Walt
 
I've a friend who told his dad used a piece of leather to shim a couple of rods on an old babbit-pounding chevy six. He had removed all of the factory shims, and it started knocking again, so off went the rod caps, and in went the leather shim. Once in a while it would knock, so he would check to find the leather had shimmied out, so he'd put it back and it would soldier on.
 
Mr 42 said:
I have an 59 AB that i got in parts. And it was shimmed with aluminium foil, and it seam's to have worked OK. But its a bit odd in my book.
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This was not uncommon in the "Old Days". They even made special tapered shims which were thicker in the center and thin on the ends which worked better then constant thickness shims. We would only use them in the cap. This was to compensate for wear on the crank. I used a lot of them while as a kid, working in a repair shop doing "Ring and Valve" jobs. That was more then 50 years ago.

Chris
 
Ah.. the "Good Old Days" when we filed the bearing caps, upset the size by going around the perimeter with a center punch and ball-peen hammer, all with the hope that a ring and valve job would last 90 dsys or a thousand miles, which ever came first.
I can remember when my Dad would not think of leaving Los Angeles in the late 1930's for a trip to my grand parents in Idaho without a slab of bacon in the ice chest.
The bacon made a great breakfast cooked over a Coleman stove along side the highway, however, the main purpose was to use the bacon rind in a rod bearing that has come loose.
 
I did some measurements this evening.
The crank Journal size is 2,477"

Im not so good with Inch, since im a metric man, but does 2,479" = 0,010 bearings
and with 2,477" do i need to grind it 0,20??

Or can i get away with new 0,010 bearings?
 
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As stated 2.499 is full size, so 2.479 is .020 in. undersize; thus you would need .020 bearings. If your crank is 2.477 and the journals are round you could use the crank but you may have too much oil clearance. you can check that in assembly with plastigage or by by micing new bearings I.D. in assembly and comparing that to the crank journal diameter.
 
I recently did a customers engine that broke its front main cap. Said customer could not/would not buy another block, so I ended up going through all my 'spare' main caps to see if I could match something up [long shot!!] Anyway, I found an aftermarket steel cap that measured up great seam to seam, but 0.0015" big top to bottom. I shimmed between the shell and cap to bring it within 0.0005" of round anywhere, and engine runs as good as ever! Brian ps, I would not do this to one of my own engines, but this customer was under a tight budget.
 
A well equipped and experienced machine shop can turn the faying surface of the caps a bit then reinstall the caps and line bore the main bores in the block. If there results are good you will still have good backlash in the cam gearing. Most of the old blocks could use to be trued up anyway.

kerby
 
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