BILL J. - The +.003" rings were available years ago. Not sure about now since many many things have gone NLA.
A valve clean-up, light honing of the cyl. & new rings can make a good engine. When I rebuilt my K241 almost 30 yrs ago money was tight, and the K241 had serious issues, but surprisingly the cyl walls were in decent ahape. The shop I took it to suggested KNURLING the piston, new rings, new conn rod, grind the intake valve and a new exh valve, plus plane the head smooth & flat, it was warped over 1/16th inch.
That engine ran HARD for almost 1400 hours in 20 yrs. When I pulled it apart a couple years ago I was aurprised how good the cylinder walls were with over 2000 hours on them. The factory original piston was knurled for the last rebuild, it'll get a +.010" piston this next time.
NIC B. - It's a shame what the EPA has done to the new diesel engines. The exh. pipes on them actually stay perfectly clean, or at least they should, NO soot or carbon inside them at all. Diesel rated oil actually has more detergents in it, those oils are coded C-something, like CD, CJ, CI, and even CI-4, etc. Spark ignition engine oils, for cars, etc are coded S-something like SJ, SI, etc. The diesel engines still create lots of soot, and that requires the heavier dose of detergents even though newer diesel's seldom ever emit visible black smoke. The "DEF", Diesel Exh. Fluid, along with additional diesel fuel is used to burn off the soot accumulated in the soot filter on the new engines. The new diesel engines that do use DEF seem to perform better than those that don't use it.
Diesel engines have higher compression pressures than car engines due to the high temps they need to fire off the injected fuel, typical compression ratios are 14 to 18+ to 1, cranking compression should be over 400 PSI to get the temps necessary, but the valve seat pressures are actually fairly low. You compare the valve spring pressures required for a high winding small block capable of running 5000-6000+ RPM and they have much higher valve spring pressures, and lifter to cam load pressures than any diesel. Those small blocks need the ZDDP, my old '96 PSD actually has roller cam followers & rocker arms so actually doesn't need much if any ZDDP at all, but according to Rotella's tech line when I called them last week, they still put 1400 PPM of ZDDP in all their diesel oils which is enough to prevent cam/lifter wear on any diesel or Kohler & Onan engine.
But I agree with your bottom line, Diesel oil is a better oil. I use it in ALL the old engines of my Farmalls & Cub Cadets. Not sure what Dad used in the '51 M for oil, or how often he changed it, but it was sludged up pretty good when I got it 6 yrs ago. I know for sure he used detergent oil, but two changes with 15W-40 Rotella T and ALL the sludge was gone. When I had the valve covers off my PSD around 250,000 miles to replace the glow plugs there was NO SLUDGE anywhere inside the valve covers. Rotella's stronger detergent package works GOOD!
A valve clean-up, light honing of the cyl. & new rings can make a good engine. When I rebuilt my K241 almost 30 yrs ago money was tight, and the K241 had serious issues, but surprisingly the cyl walls were in decent ahape. The shop I took it to suggested KNURLING the piston, new rings, new conn rod, grind the intake valve and a new exh valve, plus plane the head smooth & flat, it was warped over 1/16th inch.
That engine ran HARD for almost 1400 hours in 20 yrs. When I pulled it apart a couple years ago I was aurprised how good the cylinder walls were with over 2000 hours on them. The factory original piston was knurled for the last rebuild, it'll get a +.010" piston this next time.
NIC B. - It's a shame what the EPA has done to the new diesel engines. The exh. pipes on them actually stay perfectly clean, or at least they should, NO soot or carbon inside them at all. Diesel rated oil actually has more detergents in it, those oils are coded C-something, like CD, CJ, CI, and even CI-4, etc. Spark ignition engine oils, for cars, etc are coded S-something like SJ, SI, etc. The diesel engines still create lots of soot, and that requires the heavier dose of detergents even though newer diesel's seldom ever emit visible black smoke. The "DEF", Diesel Exh. Fluid, along with additional diesel fuel is used to burn off the soot accumulated in the soot filter on the new engines. The new diesel engines that do use DEF seem to perform better than those that don't use it.
Diesel engines have higher compression pressures than car engines due to the high temps they need to fire off the injected fuel, typical compression ratios are 14 to 18+ to 1, cranking compression should be over 400 PSI to get the temps necessary, but the valve seat pressures are actually fairly low. You compare the valve spring pressures required for a high winding small block capable of running 5000-6000+ RPM and they have much higher valve spring pressures, and lifter to cam load pressures than any diesel. Those small blocks need the ZDDP, my old '96 PSD actually has roller cam followers & rocker arms so actually doesn't need much if any ZDDP at all, but according to Rotella's tech line when I called them last week, they still put 1400 PPM of ZDDP in all their diesel oils which is enough to prevent cam/lifter wear on any diesel or Kohler & Onan engine.
But I agree with your bottom line, Diesel oil is a better oil. I use it in ALL the old engines of my Farmalls & Cub Cadets. Not sure what Dad used in the '51 M for oil, or how often he changed it, but it was sludged up pretty good when I got it 6 yrs ago. I know for sure he used detergent oil, but two changes with 15W-40 Rotella T and ALL the sludge was gone. When I had the valve covers off my PSD around 250,000 miles to replace the glow plugs there was NO SLUDGE anywhere inside the valve covers. Rotella's stronger detergent package works GOOD!
