Clutch Fan distance

[omc4u]

Hello everyone,
I apologize if this has been posted already, but I have searched and cannot seem to find the information. Does anyone know the distances below? Currently I only have 3 1/2 inches from the front face of the water pump mounting plate to the radiator, the PO did not have a clutch fan on it and trying to get it back to correct. I was trying to order a Derale clutch but the one they list seems way too thick.

1. Front of the water pump to the radiator
2. The thickness of the clutch fan, from back of flange to the front.

Thanks in advance for all your help.

[OldRusty1]

Your 3 1/2" is correct. The fan clutch arrangement was the set-up for A/C cars; non A/C cars used a fixed 5 blade fan with a spacer. I put the 7 blade fan clutch package on my non A/C '62 for the additional cooling when hot and freewheeling at cruise. Works great and looks/is stock, if it was an A/C car!
You will need the Short Shaft Fan Clutch with the 7 blade fan. I got my parts from The Bird Nest:

http://www.parts123.com/parts123/dyndet ... uKeY=AAAPT
http://www.parts123.com/parts123/dyndet ... &uKeY=2584

[omc4u]

OldRusty,

Thank you for the confirmation, I am placing an order this week. One step closer, thank you again.

[OldRusty1]

Glad to help, enjoy your Bird!

[GeoffInCarlsbad]

G'day y'all!

I friend of mine recently suggested putting a fan-clutch on my no-AC '61. What are the advantages/dis-advantages of using a fan clutch on these old 390's? Mine runs hot-blooded, so maybe a way to keep the temp down without messing with my thermostat?

Any suggestions/cautions/general advice always appreciated.

~g

[omc4u]

Geoff,

So the way I understand it from an automotive engineer is that the fan clutch helps reduce load on the engine during start up. If you think about it, that large 18 in fan gives some serious bang upon starting. Now if we talk thermal vs non thermal that is a little different. At low temps the clutch will turn about 20-30% speed based on he type you have and at temperature it can turn anywhere from 80-95% shaft speed. This allows the engine to not rob HP when it is not needed and engage only when needed. If your running hot you could have different issues. I would start with a 160F degree thermostat. Hope this helps.

What kind of fan are you currently running?

[GeoffInCarlsbad]

Today it's the stock 5 blade fan (no AC), always running. Replacing the Thermostat may be a good idea as well, since it was another suggestion to help cool the engine better. Per my gauge, I don't run particularly hot as measured, but who knows how accurate that gauge really is.

I may go down the thermostat replacement route too. Ultimately I am working to reduce my hot-start challenges.