Dick L.

In regards to the CA compression, could it be all the later CE engines increased to 6.2?

IT manual lists B-C-CA motor 125 inch... compression ratio 4.7 - 5.2- 5.75 - 6.2 so it would appear it was an ongoing change over a period of 20 years. Late 50s B should be same as the CA. Early 40-41 model B would be lower like the early C.

I think what the problem is over this is alot of sources show the high number for the CA and never updated the C and B numbers.

Not looking at the publications and only at what makes compression in my answer below it most likely seems different because of overall changes in what was offered.
To make compression higher you have to have a smaller area in the firing chamber. The crankshaft was the same the rods were the same and the heads were the same. However the pistons were not. I have some used pistons out here that did not come flush with the top of the head which would give a lower compression. This was for the all fuel engines. Most of the C engines I have opened up had the pistons flush with the top of the head. I do not know when the all fuel engine was no longer available. If it was when the CA came out that would explain the changes in the books. If you have a B or C with 3 3/8" pistons that when at TDC are flush with the top of the sleeve it would have the same compression as the CA that does the same.

I think the CA also had a higher HIGH IDLE speed than the B's and C's. CA I think was 1750 RPM where the B's and C's were 1600.

Kent

Jeff, for the CE engine used in the CA tractor, pistons with the 6.2:1 compression ratio were used beginning with engine #CE153962... On the CA tractor, this change took place during the 1951 model year....

On the CE engines prior to #CE153962, 5.7:1 compression ratio pistons were used in the gasoline fueled Model CA tractors..........

CA is listed as 1650 governed rpm
B and C are listed as 1500 governed rpm
B with BE engine is listed at 1400 governed rpm

High idle on the B and C is 1850 rpm
High idle on the CA is 1950-2075 rpm..
Very snappy engine

Yes, you could get a distillate fueled CA.. How many were built:;;good question,?

The B,C, and CA tractors are all over fifty years old...Throughout their years, many of these machines have been overhauled more than once...Each time an overhaul in performed, it is not uncommon to install updated components.. Updated piston and sleeve kits have been used for decades... And, not to mention both OEM and aftermarket sources, and overbore kits.. Nowdays, when the head is removed from an old tractor, you can expect to find just about any type of piston.. For me, if I fould some old distillate or 5.7:1 ratio gas pistons in a CE engine, I would not reuse them.. Mater of fact; I doubt that I would reuse ANY 3 3/8" piston,,, I would most likely update to an overbore kit.. That overbore kit will work equally well in all three CE engined tractors, the B,C,and CA..The governors can be tweaked, and the carbs fine tuned....

When updated;
The tractor's former compression ratio and some original specifications ((horsepower for one)) are "history"...for that tractor; anyway.

But, when the service, operators, and parts manuals were published for a tractor, they contained the information which was current at the time of publication. And,, this information would STILL be current for an unaltered tractor, no matter how old..

Agreed!
Very few 60 to 70 year old tractors have the original sleeves and pistons. In the 1950's where I am located the talk was more horse power in the same tractor. I would guess that it would have been the exception when a larger or taller piston was available that the original would have been installed. All of Dad's Oliver tractors received M&W domed pistons when they went in for an overhaul after the new wore off. Way before they needed an overhaul. Gained a gear up on the plow.
Just priced a sleeve piston kit for an Oliver 66 and the 3 3/4" kit was cheaper than the 3 1/2" kit that was in it.