need help identifying what cooling fan came on my bbc

[atowley]

Hi guys! I am working on an old rv, its a 1983 chevy class a with a 454. I built the engine and it dynoed at 400hp but i now need a fan to cool it. From what i have found online a 7 blade 19 inch mechanical fan is about the largest gm fan that was offered, but i cant find the application where they used these fans. Its part number 3999260. Thanks for the help! And if anyone has one that would work i certainly would be interested!

[nvrenuf]

There are also differences in fan clutches too; standard, heavy duty & severe duty. The true severe duty is only available in a BBC truck with 4.56 gears.

An 83 K30 3+3 w/ 454, 4spd and 4.56 gears will have both the severe duty fan clutch and a 7 blade fan.

[tucsonjwt]

Now that you are no longer have a stock engine, I don't think you will find an exact match anywhere in GM parts listings. I have a stock C20 with a GM Goodwrench rebuilt 454 and 4:10 rear axle. I replaced the fan clutch with an AC Delco from a catalog search and it works fine. I kept the stock fan. The C20 is a camper special.

I would just go with the standard 454 fan and clutch and if it won't cool enough you can add an electric fan. The electric fan will help cool your A/C condenser. I got a fan out of a Geo Metro because it was the only one which would fit, since one side of the radiator was blocked by the factory oil cooler. The Metro fan is wired with a relay to the A/C compressor, so it turns on when the A/C is turned on.

[atowley]

Any idea what fan they used on a 454? Part numberwise

[nvrenuf]

I thought already had a part number but now wanted an application?

[enaberif]

Originally Posted by atowley

Any idea what fan they used on a 454? Part numberwise

There were 3 fans types used.. 3, 5, and a 7 blade with 3 various types of fan cluthes.. normal, heavy and sever duty.

More fan blades != better cooling. There are too many things that are in play including the radiator in use.

Unless your truck is overheating I wouldn't worry about it.

[tucsonjwt]

My 454 fan is about 18 1/2" diameter with 3.25" bolt pattern (rough measurements) and has 7 blades. It has some numbers stamped on it but I can't find those numbers online - probably obsolete: A83 140 15666 (the last 3 numbers are difficult to read - may be "8" or "9".) I am guessing that this is a severe duty fan - my truck is a camper special.

My truck stays at 160 degrees according to the stock temperature gauge in 110 degree desert heat in the summer.

I see big block 7 blade fans for sale on ebay. I would get a good used oem fan over an aftermarket fan. It looks like these 7 blade fans are pricey. I know the Delco fan clutch cost me over $100 from an OEM online retailer (I think oehq or oe warehouse.)

[atowley]

Originally Posted by tucsonjwt

My 454 fan is about 18 1/2" diameter with 3.25" bolt pattern (rough measurements) and has 7 blades. It has some numbers stamped on it but I can't find those numbers online - probably obsolete: A83 140 15666 (the last 3 numbers are difficult to read - may be "8" or "9".) I am guessing that this is a severe duty fan - my truck is a camper special.

My truck stays at 160 degrees according to the stock temperature gauge in 110 degree desert heat in the summer.

I see big block 7 blade fans for sale on ebay. I would get a good used oem fan over an aftermarket fan. It looks like these 7 blade fans are pricey. I know the Delco fan clutch cost me over $100 from an OEM online retailer (I think oehq or oe warehouse.)

Thanks for the info! Im struggling to find a large 7 blade that ran on a bbc. Lots of 19 inchers that cooled a sbc in the early 70's though. I assume those just have smaller blade pitch then the bbc fans. I was debating on trying derales 6 blade 20 inch fan. I will be running haydens sever duty fan clutch. I ran a duel electric fan setup last year on it. But wasnt happy with the results. When it got to be 80 outside i was seeing temps of 220. Too high for my liking. I will be running an aux electric pusher in front of radiator to help since the electrical is already installed. Just want to go back to a tried and true mechanical.

[enaberif]

Originally Posted by atowley

Thanks for the info! Im struggling to find a large 7 blade that ran on a bbc. Lots of 19 inchers that cooled a sbc in the early 70's though. I assume those just have smaller blade pitch then the bbc fans. I was debating on trying derales 6 blade 20 inch fan. I will be running haydens sever duty fan clutch. I ran a duel electric fan setup last year on it. But wasnt happy with the results. When it got to be 80 outside i was seeing temps of 220. Too high for my liking. I will be running an aux electric pusher in front of radiator to help since the electrical is already installed. Just want to go back to a tried and true mechanical.

You can't just buy a fan and slap it on and expect to work. A properly sized fan and shroud is what you want.

Find the shroud that comes stock with a BBC measure the opening take about 1/2-1" off that measurement and that is the size you want for your fan blade.

With that setup and a 7 blade fan if you are still seeing high temperatures then electric is possibly your best bet.

[Dead Parrot]

You didn't mention what gauge you are getting your temp info from but if it is the original OEM gauge, I recommend you verify it is reading correctly before chasing a perceived temp problem that may not exist. If a PO replaced the sensor, it is highly likely it is the wrong one and the gauge is off. Assuming a 195* thermostat giving a coolant temp of around 210 once everything is warmed up, a gauge only 10% off could read either 190 or 230 depending on which way it was off. A 5% error gives you the 220 you are worried about. Its possible you don't have a cooling problem at all.

As a reference point, the fan on my 75 SBC is about 20" diameter, with 7 blades and depth/pitch of about 2.5".

[atowley]

Originally Posted by Dead Parrot

You didn't mention what gauge you are getting your temp info from but if it is the original OEM gauge, I recommend you verify it is reading correctly before chasing a perceived temp problem that may not exist. If a PO replaced the sensor, it is highly likely it is the wrong one and the gauge is off. Assuming a 195* thermostat giving a coolant temp of around 210 once everything is warmed up, a gauge only 10% off could read either 190 or 230 depending on which way it was off. A 5% error gives you the 220 you are worried about. Its possible you don't have a cooling problem at all.

As a reference point, the fan on my 75 SBC is about 20" diameter, with 7 blades and depth/pitch of about 2.5".

I am running an aftermarket gauge.

[tucsonjwt]

I personally favor the stock temp gauge. I would look for the factory parts. From what I have read, the aftermarket fans and clutches are not as good as GM or Delco parts, and local mechanics I have talked with on the subject will only use GM or Delco fans and fan clutch parts.

[enaberif]

Originally Posted by tucsonjwt

I personally favor the stock temp gauge. I would look for the factory parts. From what I have read, the aftermarket fans and clutches are not as good as GM or Delco parts, and local mechanics I have talked with on the subject will only use GM or Delco fans and fan clutch parts.

Problem is that most fan blades to install will have to be found at a junkyard.

[atowley]

Originally Posted by enaberif

Problem is that most fan blades to install will have to be found at a junkyard.

Thats a bummer too. Because all the yards around me in MN. Have scrapped their old stock. Very hard to find 70's rigs now. I just found a 7 blade 18 inch chevy fan on ebay for 60 bucks. Going to try that route for the fan. It came off of a chevelle with a big block. 2.25 inch blade pitch so it should move some major air. Now i have to build a shroud. I cant find a shroud for my rig. The fan is offset to the left center of radiator.