blue_tractor_man
Member
I am in the process of bringing back to life a Kohler L600 powered 6500 watt generator. Theses are supposed to be very high quality machines. It is a flathead, 4 cylinder engine with cast iron pistons that operates at 1800 RPM. It has an updraft carburetor.
Kohler built and sold this engine up until 1985, way past the hayday of the flathead engine. They began building this engine around 1948, and it followed an overhead valve engine that ceased production that year. This L600 engine was a 6.5 to 1 compression ratio to the end in 1985.
Here's my question, and I think I can make it tractor related:
Kohler had good engineers then, and still does today. Why would they continue to build a flathead engine 30 years after the auto manufactures began using overhead valve engines? I read everything I could find on the internet on this subject. The consensus out there is that low octane gas, low compression, and low RPM's all negate the advantages of overhead valves. Only with the advent of higher octane and higher RPM's did the OHV engine surpass the flathead. The flathead has the advantage of less moving parts. You cannot raise the compression by shaving the head without crowding the valves and reducing flow.
Now to the tractor part. It would seem that some of you guys who are familiar with the older tractor models might be able to point me to Nebraska Tractor Test results where there was one tractor with a similar sized flathead engine that might be compared with a comperable OHV engine. Tractor engines should run in a similar RPM range to the generator. I would be intetested in the HP and fuel consumption in those two style engines.
I know that all of the manufacturers went to OHV, but was there a significant difference to the flathead?
Kohler built and sold this engine up until 1985, way past the hayday of the flathead engine. They began building this engine around 1948, and it followed an overhead valve engine that ceased production that year. This L600 engine was a 6.5 to 1 compression ratio to the end in 1985.
Here's my question, and I think I can make it tractor related:
Kohler had good engineers then, and still does today. Why would they continue to build a flathead engine 30 years after the auto manufactures began using overhead valve engines? I read everything I could find on the internet on this subject. The consensus out there is that low octane gas, low compression, and low RPM's all negate the advantages of overhead valves. Only with the advent of higher octane and higher RPM's did the OHV engine surpass the flathead. The flathead has the advantage of less moving parts. You cannot raise the compression by shaving the head without crowding the valves and reducing flow.
Now to the tractor part. It would seem that some of you guys who are familiar with the older tractor models might be able to point me to Nebraska Tractor Test results where there was one tractor with a similar sized flathead engine that might be compared with a comperable OHV engine. Tractor engines should run in a similar RPM range to the generator. I would be intetested in the HP and fuel consumption in those two style engines.
I know that all of the manufacturers went to OHV, but was there a significant difference to the flathead?
