Returning to 1949, I decided to hand it over to the state.

It's important to understand that if you want to completely convert a gasoline engine into a diesel engine, you have to completely change the core mechanical structure.

This kind of cross-fuel modification is almost equivalent to redesigning an engine.

From compression ratio and ignition method to cylinder block strength, piston structure, fuel supply system, and even cooling and lubrication circuits, everything had to be overhauled and rebuilt.

The good thing is that the structure of gasoline engines in this era was much simpler than that of modern engines in later generations, which are filled with electronic control harnesses and various sensors.

Ultimately, it's just a crank-connecting rod mechanism with reciprocating piston motion, plus a carburetor.

It's purely mechanical and physical; as long as you have steel and a machine tool, you can make it entirely by hand.

At this moment, Ansteel has no shortage of experienced master craftsmen.

What's more, there's Zhou Chunsheng, a true technical expert, here to support us.

Zhou Chunsheng was a top student who graduated from the Department of Mechanical Engineering at Tokyo Imperial University. His theoretical foundation and engineering drawing skills were absolutely top-notch for that era.

With Jiang Fan added in, there won't be any problems as long as the two of them work together.

With time running out, Jiang Fan didn't hesitate any longer and immediately pulled Zhou Chunsheng along to begin the evaluation, mapping, and theoretical design of the engine.

The two men plunged into the tank, climbing up and down, each holding a vernier caliper and a notebook, and began to meticulously measure each part.

Cylinder block, piston, connecting rod, crankshaft, camshaft, valves, flywheel, oil pan...

They meticulously recorded the exact dimensions and wear condition of every single part.

Zhou Chunsheng's engineering drawing skills are indeed excellent. With just a pencil, a set square, and a compass, he can perfectly unfold complex three-dimensional parts into standard machining drawings on the blueprints.

Meanwhile, Jiang Fan was checking each measurement data repeatedly in his mind, while rapidly calculating the changes in force after the engine was converted into a diesel engine.

"Engineer Jiang, the design drawings for the cylinder bore and stroke have been completed."

Zhou Chunsheng leaned half his body over the cylinder head, measuring it several times before finally raising his head and saying earnestly:

"The cylinder diameter is 92 mm, the stroke is 100 mm, and the total displacement is approximately 2.6 liters."

Jiang Fan immediately went through it in his mind:

"The displacement is quite large. Based on that, the factory power rating should be around 30 to 40 horsepower."

"But this thing is a typical gasoline engine, with a high RPM range for maximum torque output. It needs to be revved up to four or five thousand RPM to deliver its full power. The diesel tractor we're making, on the other hand, emphasizes low-end torque. It needs to deliver its peak torque around 2000 RPM."

"Therefore, the compression ratio must be changed."

Upon hearing this, Zhou Chunsheng frowned, holding a slide rule in his hand, and while rapidly pushing and pulling it to calculate, he said:

"The original compression ratio, I just calculated, should be around 6.5:1, but if this diesel engine is to achieve compression ignition through ultra-high pressure and high temperature inside the cylinder, the compression ratio would have to be increased to at least 16:1."

As expected of Zhou Chunsheng!

However, upon hearing the number 16:1, Jiang Fan couldn't help but click his tongue.

It's worth noting that this compression ratio is considered relatively low when applied to modern diesel engines.

But for this old relic in front of us, this is almost a hellish level of modification difficulty.

With the piston stroke unchanged, increasing the compression ratio from 6.5 to over 16 means either lengthening the connecting rod, significantly increasing the depth of the piston crown recess to reduce the combustion chamber volume, or redesigning the entire cylinder head.

Moreover, the most fatal problem is that after the compression ratio increases dramatically, the peak pressure during combustion and explosion inside the cylinder will more than double.

The existing thin cast iron cylinder block simply cannot withstand such a large mechanical load.

If you don't strengthen it and force compression ignition, the engine will explode the moment you step on the gas.

Upon hearing Jiang Fan point out these fatal hidden dangers, Zhou Chunsheng reached out and touched the thickness of the original cylinder outer wall, nodding solemnly.

"That's true. This thing was originally designed for the Japanese's lightly armored tanks."

"In order to reduce weight, they probably didn't even consider the high-load compression ignition conditions, and the redundancy in the design of the cast iron parts is extremely small."

"If we want to make a hard change, we'll have to re-mold and cast the new casting, using a higher grade of ductile iron, or try thickening the high-strength steel sleeve."

"No need to try again, just water it again."

Jiang Fan made a decisive decision: "What Ansteel has the least shortage of right now is steel. Just make a set of wooden molds according to our new drawings and recast a thickened and reinforced cylinder body."

"The wall thickness of critical parts should be increased by at least two layers, especially the cylinder liner support and the bottom crankshaft main bearing housing, which must be reinforced."

"What about the piston and connecting rod?"

Zhou Chunsheng flipped through the surveying data in his hand, his brows furrowing deeper and deeper:

"Under high compression ratio conditions, the thermal and mechanical loads on the top of the piston will increase dramatically. The original flat-top cast aluminum piston absolutely cannot withstand the high temperature and pressure of compression ignition, and it will break after only a few dozen hours of driving."

Jiang Fan quickly reviewed the internal combustion engine design materials he had crammed when making industrial science videos, and after a moment's thought, he came up with the Jiefang solution:

"The piston top has been redesigned to create a shallow basin-shaped structure with vortex recesses."

"This generates a strong air vortex at top dead center of the compression, optimizes the fuel-air mixing speed, and significantly improves combustion efficiency."

"The piston material has been changed to a high-temperature resistant aluminothermic alloy. In terms of size, the piston skirt has been lengthened downwards to reduce lateral swaying and knocking during the piston's up-and-down movement."

Zhou Chunsheng nodded repeatedly as he listened, his pencil flying across the paper as he quickly sketched the outline of the new combustion chamber, adding precise dimensions as well.

After finishing the drawing, he paused, then posed the most crucial question of the entire renovation project:

"So how do we solve the fuel injection system problem? The factory's existing equipment doesn't have the capability to machine precision plunger components."

This is indeed an extremely difficult problem.

The precision of diesel engine fuel injectors requires extremely high machining accuracy. The clearance between the plunger and the sleeve must often be controlled at the micrometer level, which is a few thousandths of a millimeter.

Given the current precision of Ansteel's outdated machine tools, let alone manufacturing them themselves, even repairing them would be a challenge.

However, Jiang Fan already had a plan and immediately said:

"Let's just use the most basic unit pump solution!"

"We put an independent oil pump unit in each cylinder, and use the cam on the camshaft to directly mechanically drive the plunger to press the oil down."

"Although this design is bulky, its advantage lies in its extremely simple structure and high reliability."

"Moreover, it relies entirely on pure mechanical transmission and does not require any ultra-high precision components. Our current machine tools can easily produce it."

After listening, Zhou Chunsheng remained silent for a full ten seconds.

He is rapidly constructing the spatial structure of this mechanical inline pump.

After a moment, he slowly nodded:

"Yes, we can directly utilize the flange position reserved on the side of the cylinder block camshaft to connect an external gear drive mechanism to supply power to the unit pump."

Upon hearing that Zhou Chunsheng had finally grasped the concept, Jiang Fan immediately instructed him to follow this general direction and finalize all the specific dimensions.

As long as the fuel supply route is feasible, as for the fuel injectors, we can simply use a low-pressure solution with one or two holes for now.

It doesn't matter if the atomization effect is a little off; tractors don't need high emission standards anyway. As long as the diesel can be forcibly injected and ignited, it can be considered a success.

After overcoming the most difficult core principle, the two of them then entered a state of complete absorption and focus.