Fan Shroud interchangebility

[RustCollector]

My Series 3 plastic fan shroud has the lower edge completely busted off. It's been missing since before my ownership. Does the S2 sheet metal shroud fit with minimal fuss and drilling onto the S3 rad assembly? I'm considering replacing the busted one, and I suspect there are more S2 sheet metal ones on the used market.

For what it's worth, I haven't had cooling issues so far. The new engine is almost ready to install, along with the (almost) rebuilt gearboxes, so it'll never be easier than right now.

[RustCollector]

I should have looked around a bit before posting this. Pangolin has the plastic ones for reasonable money ($75), so I'm going to go that route.

[series guy]

Path of least resistance. Good idea.

[RustCollector]

Mark, yes the easy way is sometimes a good way to go.

I had assumed that plastic shrouds were no longer available "new". I'll check with Pangolin first next time.

[TedW]

Do these really make a difference?

[siiirhd88]

Do these really make a difference?

For low speed driving the fan shroud can make a big difference in cooling. Without the shroud in place the fan will pull in air from the engine compartment and not thru the radiator itself. At any real speed the airflow just pushes thru the radiator and past the fan blades.

Bob

[TedW]

For low speed driving the fan shroud can make a big difference in cooling. Without the shroud in place the fan will pull in air from the engine compartment and not thru the radiator itself. At any real speed the airflow just pushes thru the radiator and past the fan blades.

Bob

Makes perfect sense. Thanks, Bob!

Ted

[RustCollector]

Bob, I'm glad you mentioned that. I sort of thought that would be true. My busted fan shroud technically affected my low speed cooling, but I never had an issue on the temp gauge (we don't get 100F+ temps here that much). The big reason for me replacing mine is I just hate re-installing broken parts.

[siiirhd88]

Typical "fan science" is that the fan blades are half in - half out of the shroud. Far enough in so the fan is pulling air from inside the shroud, and far enough out so the fan exhaust is outside of the shroud. The fan diameter should be within a half inch of the shroud opening. Closing off gaps that allow air to bypass the core also helps.

Bob

[RustCollector]

My broken shroud is missing the entire bottom section. So, over a square foot of "gap" was allowing the fan to draw air from under the engine, rather than through the radiator.

Now that I'm thinking of it, I did see the temp gauge rise a bit when driving on the beach last summer. Low speeds, engine working hard, not enough air flowing through the rad. That makes sense now.

Andy

[MilesBFree]

Does the heavy-duty 8-blade fan fit in the standard shroud? Not sure I have the old fan around to measure, but I have been thinking I would like to add the shroud (my truck didn't originally have one or it was long gone before I bought it).

[Bud]

it does. the 8 blade is a serious fan and must be used with the accompanying pulley

[RustCollector]

A friend had the 8 bladed fan on his right hand drive 2A, and it had a two-belt pulley system. The crank, water pump, and dynamo had double-belt pulleys. I'm not sure if this was a tropical option, or a military thing. I'm not sure where on the globe you might need that set up, but Pennsylvania (where the truck lives) surely does not get hot enough to need it.

[siiirhd88]

The 8 blade fan was typically on military trucks that spent time either idling or at low speed in convoy, activities that limit air flow thru the radiator. When traveling at normal speed the fan is not really needed, which is why the clutch fan is used on the newer trucks, The fan clutch locks up as the air temp behind the radiator rises, otherwise the fan blades freewheel.

I used the 8 blade fan on my Pa. operated truck and noted better cooling in traffic.

Bob

[series guy]

The 8 blade fan was originally a military thing but in the late 60s the Saudis placed a big order for 88” trucks with sun sheets on the hard top and 8 blade fans among other minor changes. The story goes that the order was cancelled mid shipment and the trucks came to the USA. Our 1970 late 2a was one of these trucks.