8BA crankshaft question

3twinridges

3twinridges

Well-known member
Got the last piston in today. Took a while to set all the ring gaps and test rod bearing clearances. Have in between 0.0015 - 0.002 all the way around on the rods. The Hastings rings were much easier to work, some were dead on, and some I had to take a hair off. Compression rings around 0.012 and bottom oil around 0.013 to 0.014. Takes a little under 35 lbs torque to turn over so I don’t think I have anything binding or out of spec.

One worry I have, when I sat back and admired my work, it looks like the crankshaft flywheel flange is awfully close to the block on the drivers side. I put some feeler gauges in there and it’s close to 0.045 gap, wider on the passenger side, maybe 0.065. I realize that might be OCD, but thoughts on that?

JB
 

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3twinridges said:
Got the last piston in today. Took a while to set all the ring gaps and test rod bearing clearances. Have in between 0.0015 - 0.002 all the way around on the rods. The Hastings rings were much easier to work, some were dead on, and some I had to take a hair off. Compression rings around 0.012 and bottom oil around 0.013 to 0.014. Takes a little under 35 lbs torque to turn over so I don’t think I have anything binding or out of spec.

One worry I have, when I sat back and admired my work, it looks like the crankshaft flywheel flange is awfully close to the block on the drivers side. I put some feeler gauges in there and it’s close to 0.045 gap, wider on the passenger side, maybe 0.065. I realize that might be OCD, but thoughts on that?

JB
Click to expand...
571956
 
That area of the block is not machined for clearance the as cast clearance is plenty. So overall there's nothing to worry about you will be fine. The lbs torque to turn the engine over is actually very impressive you certainly did good. The lbs to turn Once the oil pan rope seals are installed the lbs to turn will increase a lot. As a point of interest on many of todays flathead engine builds the lower oil ring is not used. There's really no need for two oil rings so eliminating that lower ring will help reduce drag and a bit of heat from friction both being a good thing.
Ronnieroadster.
 
Ronnieroadster said:
That area of the block is not machined for clearance the as cast clearance is plenty. So overall there's nothing to worry about you will be fine. The lbs torque to turn the engine over is actually very impressive you certainly did good. The lbs to turn Once the oil pan rope seals are installed the lbs to turn will increase a lot. As a point of interest on many of todays flathead engine builds the lower oil ring is not used. There's really no need for two oil rings so eliminating that lower ring will help reduce drag and a bit of heat from friction both being a good thing.
Ronnieroadster.
Click to expand...

Thank you sir, one worry behind but a bigger one that I will post a new thread on!

I thought about leaving off the bottom ring, it’s your standard oil ring. But the 3rd is the 3 piece type and I wasn’t sure it could do it by itself. I should have went Ross 3 piece but already bored for cast egge 4 ring.

JB
 
Last edited:
Just a note. I left the bottom ring off my last build with no problems. I did have the assembly balanced without it.
 
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