Help with this 8BA

V

Vonn Ditch

Member
So I bought a basketcase 49-53 Flathead that had been stored unassembled for years. We pressure washed and cleaned it up and checked it with magnaflux. No cracks presented themselves. It's a standard bore with only slight ridge at the top of the cylinder. Here's the problem, the engine was taken apart and nothing was marked, rod end caps, mains, all unmarked and loose in a box. How should I proceed?
Thanks
 
Most con rods were numbered but not all. They can still be used but some form of ID check on the cap bores needs to be done. On the mains, there is a 50/50 chance you can get them back in proper order since the rear main cap is unique. All of these can be align honed at a good machine shop to eliminate worries. Check the caps for indented center punch marks too. I usually mark the with 1 dot for the front main and 2 dots for the middle. I would have the engine bored with new pistons if the wear is beyond service limits.

Consider a pressure test of the block. You can have cracks that are not visible by magnaflux. It's the only way to be sure there will be no leaks.
 
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The main caps are a simple process to assign locations because the drilling will allow only one of the caps to properly fit at the front. The bearing notch of block and cap go to the same side. Of course the rear cap is easily identified.

The rods are usually marked with L and R(for left and right) and 1-2-3-4(for front to rear). If there are no rod markings a careful examine can sometimes find witness marks to help. In the end it might be necessary to use a precision gage to sort through each rod with potential caps to find a usable set. Too, it is possible to cut and re-machine the rods making cap location a moot point. But, the expense would seldom be desirable.
 
As stated above the mains are a non-issue, there are differences between the front and the center caps (very slight, but they are different). The rods really should be reconditioned, so they would become a non-issue also.
 
Spend the $250 or so to have the block hot tanked and pressure checked to check for cracks that may not be evident to the naked eye.

I spent $250 on a NOS french crankshaft and another $175 on NOS french rods. I'd imagine you'd spend similar money to get your existing parts machined.
 
You can identify the front and center main bearing caps by.....the front cap will always have a little bump cast on the cap about 1/8". Also, the bolt holes will be centered on center cap. The bolt hols will be a liitle off-center on front cap. If rod caps are not marked, look at the matching machine marks when rod was honed. Sometimes you can see where the lines match up.
 
I appreciate the help. I've lined up someone for the pressure check, we'll see where we go from there. There had to be some reason the engine was apart, I just don't see it yet.
 
Front main bolts are different. Have large hole in center of bolt head. Have never figgered out why??
 
Your best bet is to take the rods and caps to a good machine shop and have them assembled and honed to determine whether they can be used. Have the crank measured, as well, to determine the oversize. if necessary. Standard oversize is .010, ,020, .030, and .040. Otherwise special order bearings will be needed. At our shop, we grind crankshafts and order spec bearings from Mahle. Most "basket case" engines have some surprises.
 
Take the front and center main caps and lay them on the bench upside down, you'll see the front cap bolt holes are off set and the center cap the holes are in the middle, The 8BA style engine like yours, I don't think I've ever seen one that rods were not marked, the L1 R1 ect rods were on the 48 and older engine, yours should be stamped 1----8 on the cap and rod. Walt
 
As several have said above, the rods should be reconditioned which is basically milling/sanding the cap then boring/honing to size. The issue I'd be concerned with is making sure you take the time to match the caps so the side load surfaces are perfectly even at the parting line. This surface can't be corrected during reconditioning.

Lonnie
 
Ok got it. The rods are indeed marked 1 through 8. A wire brush is your friend. Thanks Walt. And......there is a small "bump" on top of the front main with the offset bolt holes. My apple crate full of parts are now all matched up on the bench waitin' to see if the block will pass the pressure test. Thanks to all.
 
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