8BA Rod Question

Joe AZ

Joe AZ

Senior Member
I've pulled my '40 engine, which has been updated with 8BA rods, one piece valve guides, etc.
When removing the bearing shells, I noticed that not all of the rods have the small hole drilled, which lines up with the hole in the bearing shell.
I also noticed that at least one journal has a rod with the drilled oil hole.
Is the theory that both shells on one journal can receive oil from one rod, or should I drill those that haven't been?
Not an engine builder, but trying to learn!
Any opinions would be appreciated.
Joe
 
sounds to me that someone put 8BA rods on a 59 Crank. Not a very good idea, but it works, never thought it would but the small end play allows the rod bearings to get sufficient oil.
 
Joe AZ said:
I've pulled my '40 engine, which has been updated with 8BA rods, one piece valve guides, etc.
When removing the bearing shells, I noticed that not all of the rods have the small hole drilled, which lines up with the hole in the bearing shell.
I also noticed that at least one journal has a rod with the drilled oil hole.
Is the theory that both shells on one journal can receive oil from one rod, or should I drill those that haven't been?
Not an engine builder, but trying to learn!
Any opinions would be appreciated.
Joe
Click to expand...
Could be wrong but I believe you are talking about the appox. 1/16" oil squirter holes in the rod. Some of the early 8ba rods did not have this feature. They were added to squirt oil on the back sides of the pistons and cam lobe area. Probably won't make much difference if you did not drill them.
 
Joe AZ said:
I've pulled my '40 engine, which has been updated with 8BA rods, one piece valve guides, etc.
When removing the bearing shells, I noticed that not all of the rods have the small hole drilled, which lines up with the hole in the bearing shell.
I also noticed that at least one journal has a rod with the drilled oil hole.
Is the theory that both shells on one journal can receive oil from one rod, or should I drill those that haven't been?
Not an engine builder, but trying to learn!
Any opinions would be appreciated.
Joe
Click to expand...

Are you talking about the bearing holes lining up with holes in the rods or the holes in the crank ? If you are talking about the drilled rods, not all 8ba rods were drilled, depends on the year. Looks like a rebuilder assembled this engine from many different parts engines. Not to worry.
 
Thanks guys.....Ron, could you expand on why it's not a good idea to use 8BA rods on a 59 crank?
Joe
 
Some years ago when I had my 39 Ford engine rebuilt by one of the authorized Ford rebuilders, the only way they would do it was to install an 8BA crank, rods, main seal holder, and pistons (bored to 3 3/16). Basically they used 50 Ford rotating parts.
Tom
 
The 99, 59, and 8BA have the same dia. crank Journals, so you can use either Floating or lock in bearings. However only the 8BA crank has the dual oil holes for the lock in bearings. It's been thought that the single hole crank could not support the lock in bearing, but the fact that the /006-8" side clearance does not affect the lubrication of these bearings. It's just not a good engineering practice to temp fate.
 
Yea Ron, your right, I have stripped 59Ab engines and found 8BA rods on the 59 crank. The bearings looked good. but I wouldn't do it, to scarry. BTW he's talking about the squirt holes in the rods, the first couple of yr's of the 8BA didn't have squirt the holes. I wouldn't worry about not have the holes. Walt
 
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