Hey guys,
Are GM fan clutches directional? I found one I like for my 250-nova, but it had the multi-groove pulley (which is run the opposite direction) This clutch was on a late 80's sbc with three blades.
Is a fan clutch with three blades enough for an almost stock 250 & power-glide trans, with no a/c? I will try install/make a fan shroud... If that is still is not enough I would just add small pusher fan on the front.
Is this all a good idea?

no, you need a 5 blade. chevy 6's are know to be hot running engines hence the excessive wear on the front 2 cylinders. i run a 160 stat to compinsate for this and have good results also a 5 blade gm fan and no clutch but i work my truck. jmo
bob

They are directional. Most serpentine systems on V8's are reverse flow from standard V belt fans.

The good news is. Most Inline 6 water pumps can reverse and still pump just fine. You need to look at the water pump vanes and see if they are curved or straight. Curved = directional.

I see no reason the 3 blade will not work. You make a good shroud and try it. You may have to buy a 5 blade later. That 3 blade was used on 305 V8 and possibly 350's.

I run a 190 stat in my stuff. Goal is to get the temp up fast to get a normal size on pistons/ block soon as possible. This slows wear. Also keeps the engine cleaner by getting the oil hot enough to evaporate any condensation that gets into it from the heat/ cool process.

Just wondering if you had tried to run a water pump backwards & recorded the results?

Also, what is the difference in oil temps between a 160 T-stat vs 180 & 195?

MBHD

Never tried running one backwards, have put some thought into it though. The pumps with cast vanes are ussually straight finned and will pump no matter which way they are turned.

Bet the oil is 20 degrees hotter with a 180 and 30 degrees hotter with 190. Never recorded the results on a street car. Did on the dyno. It gets over 200 pretty easy.

All I am trying to say, is, 160 is too cool for a street engine in a car. A hard working truck or race car is a whole different application.

"The good news is. Most Inline 6 water pumps can reverse and still pump just fine. You need to look at the water pump vanes and see if they are curved or straight. Curved = directional."


I know watewr pumps can be directional, but that will be stock chev 250 driven by v-belts. I just want to use the clutch & blade. I think if I turn the blade around, it would work just the same... Is this correct? Currently the car has the stock solid 4 blade fan and there is very minimal room between the pulley & rad. The clutch I found is the shortest one I seen.