[a66coup289]

The circular circumference is the important part about a shroud. When the fan is running inside that cylinder, the air is forced to flow axially, through the propeller. Without it, a fan is only about 70% effective. 30% of the air just "swirls around" the outside of the fan.

You want your fan to make the air "travel" not just stir it up in place. And you don't want the fan to pull any of its air from this side of the radiator, you want to suck outside air inward through the radiator vanes. So the shroud makes the fan itself more effective at making the air "travel", and it ensures that all the air has to come from out in front of the radior.

I may be overthinking it. It could well be that your diesel will run cool, and 70% axial flow will be fine. But if it does struggle, I wouldn't look to add a larger radiator, I'd look to add a fan shroud.

Bob

A Spal fan is an electric fan that by nature of the mounting housing forms it's own shroud. Granted, it is more of a round shroud, thus leaves the corners of the radiator without fan coverage.

I see I am late to the party and posted before seeing the pictures.

 

[a66coup289]

So been about a week since I have been able to do any major work on the Super 446.

I pretty much finished up the engine. The only things I have left to do is rebuild the injectors and adjust the valves plus do a compression test for a base line. I tore it apart to a short block just to check everything because it was sitting in a warehouse for several years after it was pulled from the sailboat. I'm glad I did..... there was a lot of sludge in the oil pan which I'm just going to assume it was from sitting. There were spots left on the cylinder walls from where the pistons sat in place. You can't feel them but you can see them.

Otherwise the inside of the engine is immaculate and really does look like it only has 500 hours on it like the hour meter said.

I did have to clean/rebuild the entire fuel system though. The diesel dried in place and the injection pump was stuck. I unfortunately broke the rack to move it into postion so I could remove it from the block. I took it all apart soaked everything in acetone, cleaned it all up and reassembled it according to the service manual. Doing this myself saved at least $500 from what a few shops quoted me. I never did any major diesel work before but it really isn't nothing major or anything to be scared of. Follow the manual and as long as you have a decent mechanic background you should be fine.

Unfortunately the injectors are stuck too. I have them apart, and cleaned.... gonna give it a whirl to put them back together once the injector tester gets here. I may have to replace the needle assembly in each, guess it depends if they'll hold pressure or not. Manual says they need to hold 1650 psi for 10 seconds with out leaking. They pop at 1700 psi. New needle assemblies are $94 each from John Deere but a new injector is $195. There are tons of options all over the internet and eBay but I'm pretty sure three injectors for $100..... yeah probably garbage.

Anyway the fan came today. The motor is in its final resting place and thankfully everything will fit and I can keep the hood in the oem location which is great. It won't look weird at all. The only cutting I'll have to do is where the frame gets taller in the rear where the Onan originally sat. The brake pedal is definitely gonna have to be reworked but I'd rather that than moving the hood around and looking weird.

Lots of room in there between the fan and pulleys. So far I'm extremely happy with how everything is fitting. I just need to design the mounting plates and get it tacked into place. Then I run the fuel lines and add a return line to the fuel tank. Then I can test fire it!

I would put a couple little overs over where the fan overhangs the radiator so that it has to suck all air through the radiator and call it a day. The little corners of radiator not covered by the fan will not impact cooling that much.