The 'Maverick' Classic Porsche Forum and Classic Porsche Club for Porsche 356, Aircooled Porsche 911, Porsche 912, Porsche 914 & Porsche Replicas. 'We join for the cars but stay for the people'
The main difference between the 2 set-ups is that the earlier 'small' fan as used on the Factory's competition 911's utilised a fan housing with a smaller outer diameter - hence it requires an engine (fan) shroud with with a smaller 'hump' over the fan.
The 'small' fan fitted to '78/'79 SC models utilised a fan housing with the same outer diameter as the std 245mm fans - hence it will fit within an engine (fan) shroud with a std sized 'hump'.
You can use a '78/'79 SC fan with a repro 911R/RSR fan housing but all these parts have become much more difficult to find (at 'sensible' prices anyway !)...
Doesn't Nick Fulljames have a source of repro 'small' fan housings that he uses ?
Andy
“Adding power makes you faster on the straights; - subtracting weight makes you faster everywhere”
I hadn't planned HB's, a Marelli dizzy or a racing oil filter either but my thinking is fluid Ian! ......initial thought was to use my existing fan housing with a larger clear shroud but can't help myself!
Nick suggested Eleven Parts or EB Motorsport who produce an aluminium reproduction racing fan....just wondered if there was an other source?
My ST build will be a car for the road, with the odd track outing. You really need to run your motor at high revs most of the time with the small fan to prevent overheating. Not an issue on a race car for the track but not so good sitting in the Sussex traffic. So standard fan and keep the engine oil cooler as per the 2247 ST motor.