Hot Rods Flathead Oil burner question

Just got the 41 on the road, and runs great. Now the problem. I burn/spray a quart of oil in 100 miles.
I had the heads off the engine, and bores were clean and smooth. I have not done a compression check yet, and the car is an original 42k mile car with service stickers in the door jamb. I have put 400 or so miles on it, and no change. I'm sure the oil rings are stuck or full of sludge, but is there any hope of something else going on? I don't see the usual tailpipe smoke that I would associate with a bad set of rings, and I am seeing blowby out of the road draft tube, but not what I would expect for that kind of oil loss. Has anybody ever tried the ATF fluid in the sump that it worked ? Is a early 221 with the labyrinth rear main and floating bearings worth the effort to rebuild versus a 239?
Thanks
Trevor

 

If never been opened or was run years ago and sat. Don't run anything to try and clean it internally until you drop the pan and take a look see.

 

If you have massive oil consumption and the engine runs good and doesn’t smoke excessively, it usually indicates worn oil ring.
Had a 300 six Ford that didn’t smoke, ( that I could see or smell) ran perfect, but would get rid of more than a quart in 100 miles. Tore it down, oil ring expander was wearing on the cylinder walls.
Could be your problem.



Bones

 

I had the engine down to just the reciprocating assembly. Pan is spotless, intake valley clean, everything that went back on is clean. I don't know why I stopped there, I guess afraid of what im finding to be true now.

 

I had a FE type Ford engine once that had the exact same problem. When I finally tore it down I found broken oil rings is all 8 cylinders. Bores were all very nice.

 

Unlike today's engines a lot of flatheads were due for a ring and valve job at 42 K and getting 60-70 K without pulling the heads was cause for bragging rights at the local cafe.
I'd check the ridge if there is one, clean it up, pop the pistons out and check things over, A ring, bearing and maybe valve job should get you another 40 K and maybe a lot more than that.

 

A lot of the difference from how long more modern engines last comes from better oils and air filters. Not sure if the flatheads are equipped with oil filters either? But for sure, valve/valve seat/piston ring materials have come a long way too.