Can anyone tell me the diameter of a 69 SB fan? My plan is to install a new aluminum rad with a 69' shroud and a new 5 blade fan in my 67'. Make a custom spacer to allow for it. I have shrouds but no fan... I scrapped them, doh! And although I could measure the shroud, I realize you need a minimum clearance for engine movement.
Better cooling for the HO350 when it goes in is the plan.
And do you reccomend a flex or solid fan? I've heard cons about the flex?
Cheers and thanks, Mark.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
Without a shroud your fan is acting as if it was only two thirds the size it actually is (the outter one third which is most of the air move) just slides off the end of the blade. The best cooling fan is a mechanical fan (the seven blade used on the BBC instead of the five blade used on the SBC) with a thermostatically controled viscus fluid clutch powering it. But it needs a full shroud that covers the hub but, not the end of the blades which should be half out of the shroud to be adjusted correctly.
A shroud can be made by you, if you can not find one, out of sheel metal (the factory units was made of fiberglass depending upon the year of your car, which you have not mentioned) and you can find one that should work in the bone yard off another car with the same size radiator and fan (18 inch fan blades and a 21 inch wide radiator core usually). Ford's have that florecent orange on black "Warning Fan" decal that often shows up on Chevy's at car shows. It may be they are using an Explorer fan shroud on their Chevy for all I know.
2/3 of the fan inside the shroud refers to the the blade width when you are looking at it from the side. So if you are looking straight down on the fan with the shroud installed you would see 1/3 of the width fan blade.
If you measure the opening of the shroud you are going to use that will tell you what diameter fan you need.
There are flex fans that will work as well but they tend to be a little noisy. I have two GM blades: a 5 blade and a 7 blade if you need measurements. There are lots of factory spacers of different lengths. I would not attempt making a fan spacer. There are aftermarket ones available if you can't find an OE replacement. A shroud spacer is alright if that is what you were referring to.
Yes, I was referring to the rad spacer. I suppose trying to make a fan spacer could be a risky venture to say the least.
The reason I'm intending to go to all this trouble, is to be honest, I don't think the 67 Grande has very good airflow through the grille and valance. The car does get pretty hot, and in traffic it goes way up. I'm told a shroud is the sure way to really improve airflow through the rad. I can bend metal and fab up a spacer that will place the rad in the correct spot, for the optimum fan shroud ratio.
One other question, I wonder if it would be possible to use 69' rad hoses to allow for the added distance from the engine. 67''s probably would be too short.
Cheers, Mark
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
And although I could measure the shroud, I realize you need a minimum clearance for engine movement.