John Deere engine design

That's what my designer brother tells me

 

I have a lot of experience with race engines as well as a degree in mechanical engineering, so I feel qualified to make the following statements:

There are a lot of inaccurate statements in the above Quote. I tried to check the referenced site but it is a map website.  

Most tractor engines do not have their valve on opposite sides of the cylinder. They are aligned length wise to simplify valve geometry.

There is not reverse flow since the valves are in the center of the bore.

The overlap is only at the end of the exhaust and start of intake cycle. While it does help draw in during intake, it does nothing for exhaust.

Just because it is crossflow does not allow more room for bigger valves or for more separation.

The exhaust flow in a normal tractor engine has to go vertically and turn to exit.

You can only way to greatly benefit from crossflow is to have the valves canted to opposite sides.

Cross-flow design does have several advantages, and it's disadvantages, but it's context-dependant.  Basically, EVERY V6 and V8 engine is a cross-flow design- exhaust manifolds on the outside, intakes on the inside.  There's a packaging necessity to the V-design- that included angle is precious real-estate.

An inline, especially an industrial engine, has some different character, and one of those is the camshaft position, and auxiliary power-take-off.  On an inline, the camshaft sits low, and close to the line of the block, with pushrods coming up one side of the bank.  A cross-flow head would have pushrods coming right through the area of either intake or exhaust porting... which makes for difficult plumbing in those castings.  By keeping the ports all on one side, the other is totally open for pushrods.  How is this different from a V?  Simple-  the V-engine's camshaft is in the valley, but higher up, and with the bore/stroke ratio of a V being opposite from an inline, the camshaft can be mounted farther from the crank centerline to the bonus of BOTH banks.

The biggest issue of intake and exhaust temperatures on a cylinder head, is what happens to the casting under that thermal differential.  Thin castings, low nickel, with large temperature differentials tend to crack pretty darned quick.  Efficiency from intake temperatures isn't such a big deal with respect to proximity of intake and exhaust runners-  the intake air is not spending enough time in the runner to gain substantial heat... and in industrial engines, exhaust heat is intentionally added to the intake charge immediately after the carb for purpose of turning those droplets into vapor.  Air charge temperature is really most important when dealing with pulling in air that is from some confined area on a really hot day.  Oxygen density can get pretty low if you're pulling in very hot air from within an enclosure... and if it's being turbocharged or supercharged, that mixture may wind up exceeding it's autoignition temperature well in advance of it's proper event point... the process of compressing the air increases it's temperature substantially, and THAT is a good reason to have an intercooler.

Industrial inlines, especially platforms designed for a variety of liquid and gaseous fuel options, will tend to 'like' being a common-side design, because the non-plumbing side will have a large open side reserved for ignition system or an injection pump... while at the same time, the plumbing side can be easily set up to integrate a turbocharger (er... 'altitude compensator').

An engine that runs overhead camshaft, doesn't have the pushrod issue, and very frequently, since the valves are acted upon only by rockers, having a 4-valve head, and cross-flow design, results in a very high volumetric efficiency at all speeds... the cross-flow design places intake and exhaust ports, particularly the valves, very close to the port discharge point, in that case, the port volume becomes 'too small' to yield any sort of 'tuning character' to the engine's power curve... it becomes a very free-revving engine.

Industrials generally aren't that way, and any inline industrial engine that has a lower end specifically designed for multi-fuel, will not be in any sort of operational application where wide span, flattish torque curve will be beneficial.

Assuming thats a true statement, what are the advantages there???

Yes the hemi is a crossflow. One of the best. The wedge never did better on the strip. It just predated it.

On the planters, they didn't invent that either. Jon Kinzenbaw (Kinze) did the research and found that most of the JD planter unit patents were copies on old designs by other manufacturers, and copied the JD planter unit exactly (after JD refused to sell him plater units). Of course JD sued Kinze over it, but Kinze won.