B18/B20 six blade radiator fan.

I found something interesting while scrounging in the engine bay of a Amazon that was a bit too close to a house fire. A six bladed mechanical fan but small enough to fit an Amazon radiator and without a fan clutch.

It is similar in footprint to the stock metal four blade and plastic five blade fans and was mounted to the water pump with a little aluminum spacer. The blades are secured to the middle with rivets much like the later metal clutch fans.

Is this fan a niche OEM option or something aftermarket? Is it safe to run? I've heard some stories about the later clutch fans that had rivets give way. I gave it a quick repaint and it fits perfectly.

The OE flex fan was a 1970 only deal, and used with a ~7/8" spacer in the 140 application.

Much sought after back in the day for use with the early top loader smaller radiator.

NB:

Stand / keep clear when revving it up as they have been known to shuck a blade when over-revved.

The 6 blade rigid fan was part of the A/C kit. It's safe to run but most of them I see have bent blades. They're designed to be very close to the radiator and it doesn't take much for the engine to shift forward and make contact.

hiperfauto said:

The 6 blade rigid fan was part of the A/C kit. It's safe to run but most of them I see have bent blades. They're designed to be very close to the radiator and it doesn't take much for the engine to shift forward and make contact.

Click to expand...

I did notice that the fan had a spacer stuck to it by old paint. I pried that off before painting it. I am guessing that was to get it close to the radiator. Any diminished performance from removing that spacer to give a bit more clearance?

Luckily this one doesn't seem to have any obviously bent blades.

I think the fan will hit the generator pulley nut without the spacer.

hiperfauto said:

I think the fan will hit the generator pulley nut without the spacer.

Click to expand...

Surprisingly it doesn't. At least on my car with a delco alternator.