Flathead Teardown

Got a question about my project. My Merc flathead was rebuilt about 10 years ago, 500 miles before I got it. We are in the process of tearing it down and cleaning her up a bit.
Here's the deal. I pulled the heads yesterday cause they're getting replaced and one of the cylinders has some pitting way down. Not too bad mind you but enough that I'm gonna lose a little oil in that cylinder. The motor is bored .030 over and that side of the motor is sleeved. Question is, can I do a cleanup bore or go another .030 on a sleeved cylinder or will I have to re-sleeve to bore it more.
Also, what kind of life can I expect out of the rings on that cylinder. Pitting is not too bad. Can I just run it till it smokes too bad. Eventually I'll be doing a complete rebuild but I need a little more time with the motor as it is.

 

If you're planning to runnit as is, I'd say take a chance if pits aren't real deep.
On future boring--ANY Flathead Merc block can go 1/8 over unless rusted beyond belief...the great majority are good to 3 3/8, and some, especially prewar ones, run happily at 3 7/16". This is a completely different planet from modern engines that have to be tossed after .030!!
Common flathead hotrod piston sizes, after the factory standard through .080 sizes, are 3 5/16, 3 3/8, and 3 7/16. I think there are other modern choices based on metric piston ring availability, but don't know those.

 

I had the exact same problem with my 8BA. It was rebuilt years ago, then left sitting, moisture got into the the #5 cylinder causing some pitting on the cylinder wall.

I pulled the piston, honed the cylinder, put the piston back in.

I put about 3K miles on her last summer, no smoke runs like a top.

Rich

 

Thanks as usual Bruce. About the next bore job. My real question is can the sleeve be bored out or will it need to be re- sleeved. I don't know if I was clear or if you were answering yes to that.

 

The question there is why was it sleeved--cracks perhaps?? and how thick are the sleeves...maybe this engine could go to 040 or something with sleeves left?

 

Some sleves can be bored to 3 3/8.A little rust in cyl I won't worry about.Can you post pic?I reread your post ,bottom of cyl, no worry at all. Run it.